Thursday, 19 December 2013

Climate science has not failed

There has been a lot of fuss about an apparent difference between the temperature record for the past decade or so and the predictions of climate change models.  Most of what has been said shows little understanding of how models work, or what the meaning of an apparent difference really is.

Computer models of something like climate can never be perfectly accurate because climate is a chaotic and complex result of so many factors.  The way predictions are made is to run models to get a statistical ensemble - a large number of predictions that allow some degree of statistical confidence, and that also help to tell us which factors are significant in causing climate change.

Models will be run which deal with different aspects of climate.  Some will deal with sea temperatures, some air temperatures, some will look at rainfall and so on.  It is really important to understand this, because it shows that what appears to be a difference between reality and the predictions of models of one aspect of climate does not by any means indicate that the science of climate change modelling is flawed.  

Models will be run to answer different questions.  Some will be run to see how much human activity is resulting in global warming and others will be run to see where that warming happens.  This is important to understand because a lack of accuracy in a prediction about where the warming happens does not by any means indicate a lack of accuracy in predicting the overall amount of warming.

Models will be run over different time scales.  Some models are run to help find the parameters which fit past climate measurements so as to provide information to built and run models which can be useful in prediction.  Other models will be run to predict short term climate changes, others will be run to predict long term climate changes.  That some models may not fit well one time scale does not mean that other models won't fit a different time scale.

Of course not all the models will work with the desired accuracy - that is part of the science of modelling, in which development of modelling techniques is always ongoing, but a lack of accuracy in one area doesn't mean abandoning modelling, or rejecting all predictions.

Global warming has not stopped.  There has been a puzzle about where some of the heat energy has gone in recent years, but that puzzle has been solved, and with worrying consequences.  The heat energy has gone more into the depths of the seas than expected, and more into the Arctic than expected.  Extra warming in the Arctic will cause greater ice loss and more potential for feedback systems.  Extra warming in the deep seas will result in a greater tendency for areas of the sea to become oxygen-free, resulting in the growth there of microbes that produce toxic sulphur compounds.

Climate modelling has not failed; warming has not stopped, and the danger is real

Friday, 13 December 2013

There are many Quantum Interpretations!

Quantum Mechanics is strange, and we don't really have any idea of why it is as it is. We see particles apparently communicating infinitely fast to produce apparently random yet coordinated outcomes. We can predict with amazing accuracy the probabilities of outcomes and yet it seems that no-one can predict precisely what will happen. This mystery has led to a range of models of what is actually happening with quantum states, and there are more than just the two models that are widely known: Copenhagen and Many Worlds, but I'll start with those.

The “Copenhagen” interpretation of Quantum Mechanics says that quantum states remain undecided until some kind of measurement takes place, and at that time of measurement the state collapses into one of the possible outcomes. The mystery with this interpretation is that no-one can say what “measurement” actually means. It could be the interaction of the quantum state with some laboratory equipment, or it could be as soon as there is an interaction with a single atom or particle. This interpretation has led to vast amounts of nonsense about “observer effects”, in which the mind is supposed to have some role, but that's not a sensible view of things – the human mind is a physical system which is no more special than any other physical system when it comes to interaction with quantum states.

The “Many Worlds” interpretation says that quantum states don't collapse, because all the possible outcomes always happen. We don't see all those possible outcomes because we are physical systems like any other, and our existence is split when we encounter an quantum state so that there is one of us seeing each possibility. This interpretation is widely used in physics, but I find it unhelpful, as it doesn't answer the question of why THIS copy of me sees what I see – each copy of me will be unable to predict which of the outcomes it sees.

Now, some other ideas:

The “Transactional” interpretation says that as soon as a quantum state interacts with anything at all, an interaction (“transaction”) back and forth through time occurs during which one of the possible outcomes is picked (at random). The link through time avoids the issue of instant communication through space. There is no need for any idea of “measurement”, and there is no “interaction at a distance”.

Roger Penrose's quantum gravity interpretation says that quantum states can remain undecided only while they are below the level at which there is a significant difference in the gravitational effect of possible outcomes. Once that level has been reached the quantum system is forced to collapse into a single state.

I could go on and on. The point is that there are many more ways of looking at quantum mechanics. It's more than just a matter of either “observer effects” or “quantum worlds”. Right now, we have no way to determine by experiment which of these interpretations is correct, so anyone drawing any conclusions from a particular view of quantum mechanics is on dodgy ground!

Thursday, 12 December 2013

Pribble quits - but from what?

I noticed this Slate article, and it inspired me to respond, because I think it contains some significant misunderstandings about on-line communities:

I have to admit I am confused about what "on-line atheism community" is supposed to mean.  I don't see any community structure, indeed I see diverse groups with dramatically different opinions and strategies.  But going by what Martin Pribble implies - that there is an atheist approach of 'debating theists who make a ludicrous claim', then there is a simple way to avoid such debates which is to simply avoid such debates!  There is no necessary 'debating-theist' aspect to whatever 'on-line' atheism is.  There's nothing at all necessary about atheism except for not believing in gods, which is why I find it irritating when I come across phrases like 'atheists want..' or 'atheists believe...'.

But, I believe there is something important about being on-line and atheist, which is to be as visible and atheist while being purely and simply yourself.  Visibility is important, because the world will be a better place when atheism is universally considered to be a part of normal life, and that acceptance comes from familiarity.

There need be no general community and there need be no debating, but what there really does need to be is simple visibility.

Sunday, 8 December 2013

Why religion can be harmful

There are billions of believers, people who think that the world has a spiritual, supernatural aspect, and some kind of all-powerful being or beings created the world and have given us instructions about how to live.  That's the simple fact of theistic religious belief, a fact that cannot be hand-waved away with arguments about theological subtleties or politically correct insistence that we should respect different cultures.  Billions believe that the world is more than it appears to be and that the human mind is able to reach beyond the natural world.

Modern science and philosophy should leave us in no doubt that this is a mistake.   We humans have no such special supernatural abilities, and the world is a vastly larger and more complex place than was ever suggested by religious traditions.  In just about every way in which theistic religions say what the world should be they get it wildly wrong.

Now, it may be that for the majority of people religious belief is relatively harmless, providing some sort of comfort and structure to their lives, but that fact should not lead us to think that religious belief is itself innocuous.  Religious belief is factually a failed way to try to understand the world, yet in most of our societies religious belief is considered a virtue.  That's the problem, and that's how the harm from religion arises.  Religious belief is thinking without a seat-belt - the majority may drive religion safely, but all it takes is a minority to go crazy and people get harmed and even killed.

While there has to be freedom of thought, religion needs to be recognised as potentially harmful, a drug trip that can go badly wrong for some who indulge.

Saturday, 30 November 2013

Is giving advice blaming the victim?

I'm writing this because I want to understand if I my thinking is wrong, and if it is, how it's wrong.  I'm not posting any strongly-held views here, and I'm happy to be told that what I'm about to write is nonsense.  It's about violence, and I will generalise to try to avoid triggering what I realise must be terrible memories if you are a victim of specific instances of violence.

Imagine there is a certain part of town where street gangs hang out.  That area is known.  You want to go to the store urgently.  There is a short-cut through that part of town.  You are advised to avoid that part of town because it increases your risk of being a victim of violence.  Ignoring that advice, you ended up hospitalized from a stab wound.  Fortunately, you will survive.

Of course, your choice to take the short-cut doesn't in any way diminish the guilt of the attacker who stabbed you.  In a better world you would not have to worry about the choice at all.  But you did ignore the advice, and in doing so ... don't you share some of the responsibility for your situation?

The existence of those gangs is an objective fact about the world.  It's a predictable risk.  You should not have to take them into account, but if you reject their objective existence you are trying to deny the awful reality of a real danger.

My feeling is that it's a really bad idea to advise potential victims to act as if the hazards are not there, to reject any feeling of responsibility for their safety.  The world needs to be changed to remove such hazards, but also people have to be informed about the hazards while they exist, and told how to be careful.

Dangers are just as objectively real when they come from the actions of other people as when they are mindless hazards.  We have to drive carefully because we realise that other drivers can potentially kill us - one reason we put on seat belts because of the objective danger of other drivers.

I see a real problem with sacrificing the well-being of others on the altar of idealism because of the belief that warning of the dangers resulting from the behaviour of people is a form of 'victim blaming'.

People are part of the problem.  Be safe.

Friday, 15 November 2013

Science demolishes dualism

Science tells us that thoughts are the activity of cells in our brains.  Science also tell us that the activity of those cells has to have physical causes, because restrictions on physical possibilities imposed by the conservation of energy and momentum mean that there is no room for any other causes to have any direct influence on what happens in our brains.

So how do we get to have thoughts?

One is through the use of symbolic representation of abstractions combined with rules.  We can work out that 2+2=4 because we have symbolic representations of numbers and we can mentally express the rule for adding.

The other way is through input from senses and memory.  For example, we can get information from outside of our heads, such as from spoken words or things read.  These inputs result in signals within our brains that we interpret based on evolved neural functions and on experience.

Another way is through the brain combining various combinations of memories together to form imagined situation and dreams.

The key thing to realise here is that these are all completely physical processes: every thought that arises arises because of underlying physical causes no matter what that thought may represent.

This means that no thought about any aspect of our minds being non-physical can be caused by that non-physical aspect - no thoughts or feelings about our minds can be used as evidence for non-physicality.  We may have some experiences which we feel are beyond physical explanation, but we know from science that this feelings is deluding us, because all feelings must have physical explanations, otherwise we would not be able to think about them!

Monday, 11 November 2013

On-line hostility and a sense of proportion

The Internet is a big, big place.  We humans aren't used to such big places, and as a result we can get seriously misled about what is going on.  

Suppose I go onto Twitter and say something a touch controversial.  I might get quite a few heated responses.  If I'm a journalist I might get rather excited about that.  Heated responses make a good story: I can write up about how angry people get about the subject of my tweets.  I might even feel upset about the reaction to my words, and get the impression that I'm despised.  There may even be vile threats, making me feel that the Internet is not a safe place.

All of these reactions are wrong, and all arise because of a huge mistake made about the experience of being on-line:  a total lack of a sense of proportion.  "Proportion" is the right word here.  

Suppose I get a dozen angry replies.  That number is meaningless as it stands because there is no way to tell who read my tweets and did not reply.  There is no way to know what proportion of readers were angry,  because almost all reading of tweets is entirely passive.  People who aren't angry or upset usually have little motivation to reply in any way.  So what would that angry dozen mean?  I have absolutely no idea, and neither does anyone else who uses any public space on the Internet - without any idea of the total readership of a comment there is no way to know what the significance is of hostile reaction.

So, try not to get upset if you get a negative reaction - get a sense of proportion! 

Wednesday, 30 October 2013

Why Time Exists

It's quite common to come across science articles which argue that there isn't really any such thing as time.  This is a strange thing to say, if only because time is central Einstein's theories of Relativity.   It may be that time need not be present in Quantum Mechanics, but there is no evidence that QM is the central theory of physics.

However, there is a more everyday reason to believe that time exists, and that is that we have a word for an experience that we call time!  There is a thing that we use to label certain experiences of reality.  When a clock ticks, we refer to the duration between the ticks as the passage of time.  That duration is the cause of our use of the word 'time'.  

Time probably doesn't operate the way we think it does.  For example, it's not easy to understand what 'the flow of time' actually means.  But that doesn't mean that time itself doesn't exist.  Don't let the physicists try and persuade you otherwise!

Friday, 18 October 2013

Why the Many Worlds Interpretation of Quantum Mechanics isn't Deterministic

It's often said that the Many Worlds view of quantum mechanics simplifies things because it's purely deterministic - as all outcomes of quantum possibility do actually occur.  This is a mistake.  There are many problems with this view of the world, and one of them is that it doesn't in any way help with deterministic predictions.  

Consider the good old Schrodinger's Cat situation.  A cat is enclosed in a box with some poison gas and a radioactive source, which, if it emits a particle, will result in the release of the poison gas.  We wait long enough that the radioactive source has a 50% chance of emitting a particle.  Is the cat alive or dead?  The Many Worlds view says that the cat is both alive and dead, but in different realities.  This is in contradiction to the conventional 'Copenhagen Interpretation' which states that, at some point, the possibilities collapse so that the cat becomes either dead or alive in one reality.

Now suppose there is an observer O who tries to guess if the cat is dead (D) or alive (A).  In the Many Worlds interpretation the Observer O splits into two observers O1 and O2, each of which observes one of the possibilities D or A.

So, suppose the observer guesses that the cat is alive.  The possible results of the experiments are:

1. O1+D and O2+A => observer 1 sees dead cat and observer 2 sees alive cat
2. O1+A and O2+D => observer 1 sees alive cat and observer 2 sees dead cat

Which ever of these outcomes is what happens, there will always be one copy of the observer who has guessed wrong, and one who has guessed right.

Like all mainstream quantum mechanical interpretations, the Many Worlds interpretation leaves observers with points in their history which were unpredictably random.  No observer either has a fully deterministic past or a fully predictable future.

Tuesday, 15 October 2013

Our Comprehensible World

"The eternal mystery of the world is its comprehensibility" said Einstein.  No, there is no mystery; it's not hard to understand at all.  If the world was not comprehensible we would not be able to live in it.  Life needs a stable environment to arise and evolve.  Life could not appear in a world of chaos, a world with arbitrary laws where information could not collect and meaning could appear - the digitally stored recipes for building organisms.  We live in a boring region of the universe that is close to being as cold as possible - just a few hundred degrees above absolute zero, and that is nearly empty - nothing like the nuclear densities of neutron stars.  Cold and nearly empty, our world is a place where regularity can exist, where conservation laws apply because one place is pretty much like another and today is pretty much like yesterday.  Our world is full of necessary symmetries, consistencies that make life possible.  Of course our world is comprehensible - worlds which aren't are dead.

Sunday, 13 October 2013

String Theory and Narnia

I just can't read books which involve String Theory. My Spidey Science Sense starts tingling too quickly, and I can't get past the initial assumptions. OK, so modelling reality as tiny strings of energy seems to include gravity, and the model requires at least 6 other dimensions of space, and those dimensions must be small because we can't see them. I can get that far. But when the models start to deal with how strings can curl around those 6 dimensions and so on, I feel the urge to chuck the book out the window (which is a bad idea, as it's usually on a Kindle). You can't use an unverified requirement of a mathematical model (the extra dimensions) as justification for further claims about reality unless or until you have verified that requirement. The existence of the other dimensions isn't a requirement of physics, it's a requirement of mathematics. Someone has got their ontology utterly screwed up. 

String theory is like Narnia. Before you start to present ideas about the landscape of Narnia, you first have to show that wardrobes are trans-dimensional and that the specific land of Narnia lies within.

Monday, 7 October 2013

I'm an atheist but...

I'm an atheist because that's the term for someone who does not believe in gods.  It's important to let others know you are atheist because so many aren't able to do that, and because so many suffer prejudice and oppression because of their lack of belief.

But... I'm not an 'atheist+'.  It's absurd to try and associate positive beliefs about politics with the absence of belief that is atheism.  Even misogynists or racists can be atheism, and their ignorance and hatred doesn't  make them any less atheist.  Atheism doesn't have any innate political views unlike humanism.

But.. I'm not part of any atheist community.  If someone says 'we atheists', they aren't talking for me.  There can be atheist communities, people bonded together because of the consequences of their lack of belief in societies and cultures where belief is widespread and expected.  But I'm not part of any such community.  Anyone who talks of 'the atheist community' doesn't have a clue what they are talking about, as the experiences and different situations of millions can be summed up with 'community'.

I'm an atheist because I don't believe in gods.  If you want to know what I think on any issue you are going to actually have to ask me.

Friday, 4 October 2013

Why there is no soul part 3 - conclusion

I have explained how all stories about what happens in the brain and mind at different levels can be true - reductionism doesn't make the higher-level stories involving thoughts and feelings any less true.  I have shown why what goes on in the high-level stories has to be also present in the 'reductionist' levels as well, because all the stories have to proceed in lock-step: a memory is recalled, many neurons fire and change, and trillions and trillions of particles shift and change, all at once, all locked together into the story.

What this means is that thoughts about the mind are about many levels of mind and brain at once.  When there is a thought about the richness of a colour, this happens in the mind, in the neurons and in the particles.  So, the story of your thoughts is completely present In the level of physics, and all the reality is also completely present in the level of physics.  The story is both about thoughts and about physics at the same time, and if both stories are to be true, if the thoughts about mind are to be correct, then the physical story has to be right about itself.    A physical story that says that there is more than physics involved in the mind contradicts what we know about the low-level physics of the particles that make up the brain.

Therefore, the belief that the mind contains more than physics, that there is a soul, cannot be true.

Thursday, 3 October 2013

Evolution isn't always convergent!

Evolution just does it's own thing.  What may seem like predictability really isn't.  There have been suggestions, as you might expect, that evolution has targets, that it's designed to get to certain types of beings.

There was a great rebuttal to this several years ago by the biologist P.Z. Myers.  It goes kind of like this:

Look at the amazing way that evolution has shaped animals that swim fast through water.  Sharks are like super-streamlined missiles, as are barracuda.  Now look at the dolphin - apart from the angle of fins in the tail, it's the same super-fish-shape as the shark.  The fish shape is a great example of convergent evolution, of how evolution will reach the same designs for the same situation.  Hold on a minute, there's something moving very fast through the water over there - it's a squid.  Oops!

Convergent evolution can happen, but it's not inevitable.  There are sharks, dolphins... and squid!

Monday, 30 September 2013

Is it Islam's fault?

The usual back-and-forth is proceeding about the role of Islam in horrific terrorist acts.  As usual, the different sides seem to be hugely over-simplifying the situation, which is worrying as to stop such acts we need to truly understand their origin.

It seems odd to put the blame primarily on Islam for such acts when the vast, vast majority of Muslims (like any other group of people) are peaceful.  It's also a problem because Islam is so very varied, that you have to specify which type of Islam at the very least. So, if "Islam" is said to be the cause of terrorism, it's not a very effective cause.  But that doesn't mean that belief in Islam isn't involved.  There may well be a toxic brew of effects - politics, background and faith, with all three contributing to the nightmarish situation of terrorist violence.  The problem is that just saying 'it's religion' doesn't solve anything, as we have to find out how the factors interact - what the dangerous formula for fundamentalism is.

Where there really is a problem is when there is flat denial of the influence of religion, when it's taken out of the equation of extremism and not allowed to be thought of as possibly part of the problem.  This is why platitudes about "nothing to do with Islam" are irrational, and worrying.  They are a denial of the search for truth, they are question begging.

We may find that faith isn't a significant part of the problem, it may be that it's one excuse for tribalism and terrorism and others would be found if faith was not involved.  But we can't pre-judge this.

It's time to stop allowing political sensitivities standing in the way of the search for truth.  That search for truth has to involve everyone, including religious leaders.  If they are truly concerned about terrorism, they will help.

Sunday, 29 September 2013

The mind is physical

Our minds are physical.  It may be possible to imagine a mind without a human body, but it's not possible to truly conceive of a mind that is not within time and within space.  That's a strong claim, but not too hard to justify:

Everything about our mind and experience involves time.  We could not remember if there was no past, we could think if there was no possibility of progression of thoughts, we could not perform reason or experience emotion if there was no time for beliefs to change and emotions to change.  Our minds are things that continue from time to time, as the stories of our lives play out, hour after hour, day after day, year after year.

But what about space?  Consider pain.  We don't just know we have pain, we feel pain within a sense of what we are.  We can recall a toothache in our jaw, a backache in our back, a stubbed toe on the end of our foot - pain has a location.  The location may be phantom, such as referred pain (when a pain feels like it's in one part of the body but the cause is elsewhere), or pain that seems to be in a missing limb, but the confusion only reveals the significance of mental models of location.

Our experiences of vision contain dimension.  It's not possible to imagine seeing a thing without that thing having the mental attribute of size.  When we hear we often can pick up the direction of sounds, and we can imagine that direction.

There are also other dimensions of mind which are not so obvious and yet must involve physicality - the storage and retrieval of memories involves partitioning of some kind - memories have to be kept separate somehow in order for recall of distinct things to be possible.  Any form of partitioning, no matter how indirect, must involve dimensionality.

Our minds are bound to time and space, and anything that we would identify as having the characteristics of mind are equally bound.

Recognising this physicality is not any form of reduction of the status of mind, only revealing the necessary scaffolding that is needed by consciousness.

Friday, 27 September 2013

Meditation (me too!)

Sam Harris has posted an excellent lesson on mediation:

I thought it might be interesting to show how I meditate, as my method is, I believe, much easier. A couple of years ago I was taught how to get into a state of mindfulness by therapists, and it's something I do these days to calm my mind.  I find it very relaxing and peaceful.  This isn't like other approaches to mindfulness I have come across, as I don't focus on the body.

First, get into a situation where you can relax.  This can be sitting, lying down or even standing. What matters is that you can comfortably remain in that situation.  Now find something visual to focus on.  It should be something simple and calming, such as a tree out of the window.  It doesn't really matter as long as it's simple.  Now while staying as relaxes as possible focus your attention on the object, while working to keep your mind clear.  As soon as any thoughts come to mind (and they will), dismiss them. If your attention wavers from the object, draw it back gently.  The aim is to be focussed on the object while thinking of as little as possible.

What can happen after a while is you start to lose a sense of time and self.  You may find new perspectives of the object appearing - you may, for example, have a sense that a tree is filling your field of view even though it's far away.  Most importantly you should be in a state of calmness and peace, and there will be a wonderful feeling of mental relaxation.

Don't worry if this doesn't happen.  It will take practice and it may take many minutes even when it does.  What is beneficial is the act of working to clear your mind, learning to control your thinking.


Thursday, 19 September 2013

Why there is no soul - part 2 - Information

In Part 1 I explained that, at least according to what science has shown us, there can be no thoughts or feelings or beliefs or anything associated with the conscious mind unless there is activity of brain cells, activity which is itself inextricably linked to the behaviour of particles - atoms, ions, electrons.  I described what happens as a set of stories, each story at a different level of reduction, each story being true and all stories being linked.

What I'm now going to consider is where the content of the stories comes from.  The linkage of the different levels of reduction tells us something important - all the content of the 'higher' (larger scale) level of story must be present at the lower levels.  The story of the mind is present in the language of the activity of brain cells.  The story of the activity of brain cells is present in the activity of the particles.  If this were not the case, the different stories could not be as locked together as they are, a locking together which physical causality insists must be the case.

How can such complex stories be told in the language of mere particles?  It's because the relationships of particles can have endless richness.  There is no limit to what can be represented by particles linked by the known physical laws.  The simplest of mathematical systems can result in infinite richness, as we can see in the details of fractal systems like the Mandelbrot Set, and the interactions of the particles of matter and energy that make up our bodies aren't so simple.

Physics provides a fabric on which the most complex dynamic patterns can be woven, patterns that we may need to step back to the level of biology to understand.   But no matter how complex these biological patterns, all the information for these patterns is written in physics too.  I'll explore what this means in part 3.

Wednesday, 18 September 2013

Climate change and the nature of science.

Climate change is real, and it's mainly due to human production of vast amounts of carbon dioxide.  This is simply expressed, but in many quarters it's hugely controversial, when it should not be.

What's fascinating is how many people seem to have a very strange idea about how science works.

A scientist is someone who tests out ideas against reality.  A good scientist is someone who is good at testing ideas against reality.  A scientist is paid to test ideas against reality.  Scientists compete for money to do their work.  They compete against each other.  They are successful if they can show that they are better at coming up with ideas and testing these ideas against reality.  Because of this competition it pays scientists to find fault with each others work, but because science is about tests against reality, the faults must be true faults.  Scientists get to publish their work when competing scientists are prepared to recognise the quality of their work.  Science is full of competition, some friendly, some not.  Everyone is out to succeed, and reality is the judge.

Remember this:  reality is the judge.  This means that there isn't the degree of bias that you might suspect that could come from how a scientist gets paid.  The reason is that you don't hire a scientist if you know the answer you want to get - you hire someone who writes fiction.  There's no point paying for laboratory work if you know the answer you want to get.

The idea that scientists could somehow work together to invent climate change results is absurd, because scientists don't get money from working together - they are all out to find fault with each other.  And - reality is the judge.

The idea that you can pick the views of a particular scientist and say that he or she has the right view is absurd, because unless you have expertise in their field the only reason you are saying that they have the right view is because you already know what you want the right view to be.

The way a layperson should decide what is the right view to support, for now, is statistical:  what is the consensus view?  That's the only way a layperson can decide the view to support.  Anything else is simple prejudice, and a rejection of science.

So, climate change is happening, and it's mainly due to human production of carbon dioxide.  That the overwhelming scientific consensus.  If you aren't an expert in climate science and you disagree with that, then you are just making stuff up.

How do we detect curved space?

What does it mean to say that space is curved, and how do we measure it?

It's simpler to look at things in two dimensions.  Imagine a flat piece of paper.  How would we measure its flatness if we were living on the paper, like ants, not able to perceive a third dimension?  There's a neat way of doing this.  Get a ruler, and mark out a line.  Now move the ruler around, always keeping the ruler pointing in the same direction relative to yourself.  Move back to the marked out line.  If the ruler is still parallel to that line then the surface you are on is not curved.  If the ruler is no longer parallel to the line then you have moved over a curved surface.  The ruler has been twisted - not by you, but by the curvature of space.

We can do exactly the same in three dimensions.  We use a ruler, but this time, a line is marked in three dimensions.  Move the ruler around, keeping it pointing in the same direction relative to yourself.  Now move back to the original line.  If the ruler and the line are not parallel then you have moved through curved space!

Curved space is a prediction of Einstein's General Relativity, and we can actually measure its curvature using very, very precise gyroscopes, which remain pointing in the same direction.  If such gyroscopes are put orbit around the Earth and space is curved and twisted by the Earth, the gyroscopes, like the imaginary ruler, will also twist.  This has been done!

Pigluicci on Consciousness

Nice video on consciousness by Massimo Pigluicci:

I don't completely agree - I think there are more direct ways to demolish the 'Hard Problem' of consciousness, and I don't accept that 'eliminative materialism' need mean that qualia don't exist - what it means is that common beliefs about things such as qualia are wrong.  'Illusion' doesn't mean something doesn't exist - it can also mean that what we think about something is mistaken.

Monday, 16 September 2013

Why there is no soul - part 1 - reductionism

Reductionism is widely misunderstood.  It's often thought that reductionism in science means that, for example, thoughts are 'only' the activity tiny particles - atoms, electrons and ions - doing what they do according to physical law.  That's the wrong way to express reductionism.  The correct way is: "thoughts are the activity of tiny particles", but that doesn't exclude thoughts being other things as well.

What do I mean by 'other things'?  To see this, consider a computer.  A modern computer is made out of billions of tiny switches.  It's reasonable to say that a computer program consists of the settings of many of these switches, but that doesn't tell you much.  To know what a computer program actually does you need to look at a higher level, to see that this section of the code draws some graphics, and that section of the code draws a the image of a plumber, and the whole thing is a Mario Game.  Both the lower-level description of the program in terms of switch settings and the higher level of the program in terms of functions and objects are true.  Reductionism doesn't erase the higher level description - instead, it shows what the higher level is made of.

Reductionism means that more than one story of what is going on in reality can be true at the same time.  It's true that millions of switches are changing in a computer and it's also true that a computer game is being played.  Both stories can be complete, and both stories have to happen in lock-step; it's just that some stories are more useful at understanding what is going on.

Now let's look at something less directly mechanical: waves on a pond.  Drop a pebble into a pond and waves will ripple out from the point where the pebble enters the pond.  These waves may spread out and bounce of various objects in the pond and create a complex pattern for a while.  What is happening to the water can be described both in terms of waves and also in terms of the physical interactions of vast numbers of water molecules.  Again, both stories are true, and both stories have to happen.  When the wave bounces off the side of the pond, the wave story and the molecular story both describe what has occurred.

The thing that needs emphasizing here is the necessary link between different stories.  Anything that happens has to be an effect in the stories at once: nothing visible at the level of waves can happen without having a significant effect at the level of molecules.  It may be possible for molecular effects to be too small to be visible to the human eye, but the reverse is never true - there can be no waves without the movement of molecules.

This tells us important things about how our brains operate.  There are different levels of reductionism, different levels of story.  The lowest level is that of particles doing what particles do - atoms, ions, electrons and so on.  There is a higher level of brain cells receiving signals, sending signals and processing and storing signals in the various ways that brain cells do these things.  A higher level still is the thoughts and feelings and memories that are the properties and activities of our minds.

What reductionism says is that there can be no thought, no feeling, no memory, without directly associated activity in brain cells, and directly associated activity of particles.  The stories are necessarily tightly linked.

What this linkage means I'll explain in part 2

Saturday, 14 September 2013

If we came from monkeys, why are there still monkeys?

This is a broad question about how species arise.  It's sometimes answered by saying that we didn't come from the monkeys we see around us today, but we and monkeys came from a common ancestor.  This doesn't seem that helpful an answer to me, as it can't be denied that the common ancestor of humans and monkeys was more monkey-like than human-like.

One way to look at this question of speciation that might help is to think about territory. Imagine monkeys living in a large area of forest.  The forest does not go on forever, and the edge of the forest is likely to be a rather different environment than the broad area of the forest.  Then there is beyond the forest, which might be grassland.  The point is that some members of the monkey species will come across new environments, and there might be some members of those species which are more suited to those new environments, perhaps with longer (or shorter) limbs, for example.

Species can arise not because there is some constant pressure to diverge from a common ancestor, but simply because populations grown and environments aren't constant and infinite.

(Post asked for by @futbol91 on Twitter)

Friday, 13 September 2013

What is the light speed barrier, really?

What does the speed of light being the fastest possible speed really mean?  It's not as simple as it first seems. The speed limit only applies to the speed of objects seen to be passing each other.  

For example, consider a very distant galaxy.  It may be moving away from us very fast because of the expansion of the universe; its speed may be a significant fraction of that of light.  The faster a galaxy is moving away from us, the more its light is red-shifted.  Eventually this galaxy will be moving away from us faster than light, but we will never see this, as its light will be red-shifted into darkness.  We will see the galaxy disappear.

Another example is a spaceship travelling close to the speed of light.  It can, from the passenger's point of view, travel faster than light because of time dilation and distance contraction.  Accelerating at 1 g it would be possible to get to the centre of the galaxy in decades, even though its about 30,000 light years away.   However, nothing is seen to be passing the ship faster than light because distances will seem shortened in the direction of travel.  Nothing is seen to be passing the ship faster than light from outside the ship, because from that viewpoint the ship never travels faster than light!

Light speed isn't the barrier it seems to be at first - it's just the limit at which things can be seen to travel.

Thursday, 12 September 2013

Mind is necessarily physical?

We are so used to the way our minds work, it can be quite a surprise to realise what it has to do to work as it does.  Minds can make decisions, they can imagine, they can remember, they can reason.  Just looking at one of these abilities - memory - tells us a lot about what must be needed for a mind to work.

Memory needs some form of storage.  Retrieval of memory needs some sort of indexing of the storage so that the right memories can be brought to mind.  There also has to be some sort of categorisation of memory, so that the memory of something which is like another thing can be recalled.  It should also be apparent that whatever provides these memory functions can't itself be a mind, otherwise that would not explain anything - there would be a recursion.  From all this it seems clear that mind has to need some sort of physical substrate, some parts which can change state and which can interact in reproducible ways.  

So, mind seems to be necessarily something physical, because of the nature of the functionality that necessary for mind to actually do what a mind is expected to be able to do!

Sunday, 8 September 2013

Why Plantinga is wrong about human mental abilities

Alvin Plantinga questions that evolution alone can result in humans having reliable beliefs, and uses this as an argument against naturalism.  As you might expect, I disagree!

Let's take an example that has been mentioned in this context:  why would a human run away from a predator (say, a hungry tiger).  There are a large number of false beliefs that would result in someone escaping from a tiger: the tiger wants to play, and running away will be fun!  Tigers remind me of apples, so I'll go climb that tree and get some.  Tigers have some magic ability to cause floods, so I had better get somewhere high away from the tiger.

It's true - there are plenty of false beliefs that can result in escape, but these are all fragile and isolated.  A belief about a tiger won't be protective against a lion.  A belief that one should seek apples won't work if there are no apple trees.   All of these false beliefs can result in death by tiger if there is a slight change in circumstance.

True beliefs, on the other hand, are both robust and versatile.  A true belief that a tiger is dangerous because of its teeth and claws works with bears, lions, crocodiles, even snakes (just look at those fangs!).  True beliefs can survive the 'Chinese whispers' process of cultural transmission because they are hugely simpler than convoluted false beliefs, and because true beliefs are actually true - they survive continual testing against reality.  The belief that tigers cause floods doesn't survive such tests.

One basic reason why such true beliefs arise and how they persist is because what is going on in both evolution and culture is a form of science: beliefs and mental faculties are being varied randomly and tested against reality with survival as the result of successful experiments.

Another reason why true beliefs are more robust is that they can fit together: true beliefs can combine to form new beliefs which extend our ability to survive.  We know that bears are strong (one truth), and we know that their teeth are dangerous (another truth), so we should definitely avoid angry bears.

Of course, these days there are aspects of reality that are beyond unaided human faculties.  We investigate those aspects of reality using science intentionally, and not just incidentally.  We have computers that can think and reason far faster and more reliably than we can.  We have instruments that can extend the reach of our senses to astronomical degrees.

The key thing here is that evolution tends to result in reliable cognitive faculties about the environment we evolved in because evolution is itself a form of natural science - Nature tested against Nature.

Physics, homosexuality, and 'typical observers'

One of the strangest principles of physics that I keep coming across is that of the 'typical observer'.  For reasons I have never seen explained, we should have a problem in science if we aren't 'typical observers' of reality.  I have never been able to understand what this is all about, especially when physicists try and talk about future observers as if it's somehow possible to take a statistical sample which includes things which haven't happened yet!  Why 'observing' should have any scientific implication eludes me.  Does an observer have to be self-aware?  If so, why?  If not, then why aren't ants more typical observers?  What about bacteria?  Atoms?

I know that I'm not a 'typical observer' because I'm gay - so I'm not even a typical human!  I see this 'typical observer' stuff turn up in supposedly respectable articles in New Scientist.  If anyone can tell me what the point of this concept is, I would be grateful.

Friday, 6 September 2013

Sam Harris vs Sam Harris on morality

Moderator: Our two debaters here today are very well-known writers, bloggers and speaks on various subjects - morality, philosophy, science and religion. Today they challenge each other's views on the subject of morality.

Sam Harris: I believe it's obvious to any rational person that our minds are products of evolution and their thoughts and feelings are fully determined by physical laws.  This determinism is why I insist that there is no such thing as free will and why I suggest that human moral values can and should be determined by science.

Sam Harris: Hold on there a minute.  I think you are overreaching.  As I wrote in my blog entry "The Mystery of Consciousness", I don't accept that conscious experience can be fully explained by science.

Sam Harris: How is that relevant to a discussion of morality?

Sam Harris: Morality has everything to do with conscious experience.  We don't just know we are in pain, we feel pain and that is one way we can suffer.  Knowledge of pain alone doesn't cause suffering.

Sam Harris: But, using science we can determine if someone is feeling pain by examining their brain states using modern tools such as functional Magnetic Resonance Imaging.

Sam Harris:  I thought I had made clear my view that science can't fully explain consciousness.  So, you aren't going to be able to get at true conscious experience using scientific tools.

Sam Harris: That is just playing with words.  There is so much correlation between the results of scientific investigations into the way our bodies work and people's reports of pain that we can be confident about what science shows us.

Sam Harris: No - conscious awareness is what matters.  When some of that awareness is lacking in people with brain disorders the result is moral failings such as lack of empathy for others.  Empathy - one of the foundations of morality, is about what we feel when we find out about the suffering of others.

Sam Harris: Come on now, Sam.  You have just connected 'brain disorders' with 'empathy' - that contradicts your own position that science can't understand conscious experience.

Sam Harris: I said that science can't fully understand conscious experience.  I don't doubt it can make some progress, enough for some correlations; enough to identify people who have disorders of conscious awareness that reveal the vital part such awareness should have in moral questions.

Moderator: final statements please, Gentlemen.

Sam Harris: Science can determine what people will say they will experience when they experience suffering, and when their well-being is increased through the reduction of that suffering.  Science can and must be used to determine moral values.

Sam Harris:  Unless we can know what conscious awareness really is, we can never fully understand the nature of mental experiences; what it means to suffer; what it means to thrive.  And so, questions of morality will always remain to some degree purely subjective and so beyond science.

Moderator:  Thank you Sam, and Sam.  I can see that this debate will run and run.  Goodnight all.

Thursday, 5 September 2013

Why I gave up dualism through philosophy

I'm not a dualist.  I don't believe that mind and matter are in any way separate.  I used to believe this, but I was forced to rethink my position because of a clever philosophical argument - a philosophical argument FOR dualism!

The philosopher making the argument was David Chalmers, in his excellent book "The Conscious Mind".  Chalmers says that the one thing we can be sure of is our own consciousness, and we can see that consciousness isn't the same as the physical mind because we can conceive of a reality where everything is physically identical to our reality, and yet no being has consciousness.  Because we can conceive of this, then consciousness is clearly not just known physics.  Chalmers called these unconscious beings 'p-zombies' - where 'p' stands for 'philosophical'.

This convinced me for some time, until, one day, I really thought hard about it and I was shocked by what I realised.  According to Chalmers, everything that I could say about my own consciousness would be said by my equivalent p-zombie.  Except (Chalmers says) what my p-zombie says is false.  I realised that nothing I said about my own consciousness being non-physical could possibly be justified, because no matter what arguments I came up with, the same words would be spoken by my zombie twin.  Therefore, no thought I have about consciousness being non-physical can be justified by my own thinking, because whatever thinking I do, my zombie twin will report exactly the same thinking!

Chalmers' argument FOR dualism became, for me, the strongest argument AGAINST dualism.

So what was the difference between me and my zombie twin?  It took me some time to come up with an answer.  It may not be the right answer, but it's an answer that works for me so far.  The difference is that my zombie twin doesn't exist.  It's fictional.  We can have consciousness because we exist.

Wednesday, 4 September 2013

Why science needs philosophy

There's a widely held view that science can make philosophy redundant, that philosophy has a declining role in the understanding of our world.  That's wrong.  Without philosophy, science is just data collection.  Let's look at some examples.

1. Philosophy can help us understand what it means to talk about 'ultimates'.  To give an example, some String Theory says that the ultimate constituents of the universe are extremely small vibrating strands of something, and the behaviour of particles is determined by how those strands vibrate.  It doesn't take much philosophy to understand that these strands cannot be the ultimate thing because a vibrating object necessarily has identifiable parts, such as nodes of vibration.  Philosophy can lead us to realise that it may not make any sense to talk about ultimates, because philosophy can allow us to investigate what attributes some such ultimate might have, and to explore if they are consistent.

2. Philosophy can help us look at the subject of multiverses.  What does it mean for a region of space, or some spacetime domain to be a 'multiverse'.  Can a universe that does not connect to our time and space be thought of as existing at all?  This is a question of philosophy.

3. At some point we will make an artificial mind.  How do we know if this mind is conscious?  Should we grant such a mind rights?  Is it murder to turn such a mind off?  These are questions of philosophy.

4. Does reductionism make sense?  Can we explain what happens in our brains using neural networks?  Is there some extra causal effect at the level of brain cells that is just not present when dealing with the physics of the material the cells are made of?  This is, again, a subject for philosophy.

Philosophy is the process of thinking about meaning.  We will never be in a position to not have to do this, and so we will always need philosophers to help us interpret science.

Monday, 2 September 2013

Why Sam Harris is wrong about Morality and Science

This is not intended to be part of any competition, just an exploration of ideas!

I think that Sam Harris is generally right in some respects about morality, particularly in that science really can and should inform moral choices.  For example, there are matters of cultural and religious tradition that science can show are objectively harmful and cause suffering, such as Female Genital Mutilation, and scientific findings should lead to clear and unambiguous rejection of such cultural traditions.  

But, trying to pin down morality is like trying to wrestle a snake.  The problem with discussing morality is similar to the problem with discussing free will - there is such a huge disagreement about the meaning of terms that communication can be difficult.  I am a 'compatibilist' when it comes to free will - I believe that free will exists in a deterministic reality (indeed, I go further, and believe that free will needs a deterministic reality), but I recognise that this definition of free will is rejected by many (including Harris).  The same goes for morality - there are ongoing philosophical debates about moral realism: are moral values things that actually exist in some way, or are they abstractions?  While there is continued disagreement about what morality actually really is, science certainly can't determine any moral values, assuming science ever can do this.

There is also the question of what 'well-being' actually is when it comes to morality.  We have mostly moved past the view of 'spare the rod and spoil the child' when it comes to punishment of children at school, but there is still a question of whether experience of suffering is 'good for character', leading to a happier later life.  The business of how suffering should be partitioned throughout an individual's life and throughout society seems insoluble.   To use a simplistic Star Trek scenario - should the "needs of the many outweigh the needs of the one"?  Once a decision has been made about weights of needs, then science can inform us, but how to make the decision?  Is there a limit to the suffering of an individual we should allow to reduce the suffering of others?  Who decides?

Morality is a maze in which we don't even know if there are exits.  If someone decides that we should deal with the maze by blasting down the walls, science can help.  But is that a moral way to deal with the puzzle?

Saturday, 31 August 2013

The accelerating universe

In 1998 observations of very ancient and distant supernovae revealed a surprising fact about our universe: it's not just expanding, but it's expanding at an accelerating rate!  Before that it was thought that the universe would necessarily be decelerating because of the gravitational attraction of all the matter and energy.  It debated whether or not the universe would end by a 'Big Crunch', with everything compressed together, or whether it would expand on forever with the expansion getting ever slower.  Acceleration was the last thing that was expected!

The acceleration is though to the the result of a constant force which is somehow built-in to space - each volume of empty space contains something that results in this force.  There are various ideas, mostly to do with some quantum effect, but no-one really has any idea what it is, and so it's given the pretty meaningless name 'dark energy'.  

What will the future be?  Dark energy seems to stay constant in a given volume of space, so it won't ever grow large enough to rip galaxies, planetary systems, stars, or even people, apart.  All these things will be held together by the vastly stronger forces of gravity, electromagnetism, and nuclear forces.  But on larger scales the dark energy force will overcome gravity.  In many billions of years from now distant galaxy clusters will have accelerated away beyond our ability to see them.  The universe will appear much, much smaller.

Friday, 30 August 2013

What would objective goodness and badness be like?

What does it mean for some act to be really, objectively bad?  Or really, objectively good?  This is a question that has puzzled philosophers for thousands of years.  Some think that there can be no such objective nature of morality; others that there can be some sort of shared morality recognised by most mentally healthy humans, a sort of pretty-much-universal form of common experience that is a reasonable substitute for objectivity.  

But what would true objective morality actually be like?  Where could it reside external to the minds of humans and other sentient beings?   There is a problem with this, as moral standards are felt emotionally, they are connected with empathy, with conscience.   Also, a moral standard that wasn't in some way subjective would not need interpreting.  It would not be possible to think of a moral position related to that standard and have a subjective position on that standard, as then we are in the situation of subjectivity - if we are in a position to question whether or not something is really wrong, or really right, then we lose the objective aspect of that moral question.  

The problem, I suggest, is this - the only way an objective moral value can exist is if it's not possible to have a subjective alternative feeling about it.  Objective morality must mean unchallengeable consciences.   

Or does it?

How to make a time machine

As we understand physics today, time machines might be possible.  If they are possible then they have a major limitation, which is that backwards-in-time travel is cannot be before the time machine was first switched on.  The reason is that the only way we know to make time machines is to distort space and time to allow 'Closed Timelike Curves' (CTCs), and these closed curves can't loop back to before the time machine was turned on as that's the earliest that one of these curves can start.  Creating a time machine is like creating a subway tunnel through time - you can enter and exit any time along its length but you can't get off before the start.

There are many ways that a time machine might be made.  There is one idea which requires an infinite spinning massive cylinder, which doesn't seem very practical.  Perhaps the most likely way is to use a wormhole.   A wormhole is a shortcut between two points.  One point might be on Earth, the other around Alpha Centauri, and it might take only seconds to travel between these points through the wormhole.

[Just a quick point - wormholes aren't anything like as shown in science fiction TV series: they don't look like funnels.  The entrances to a wormhole are spherical, not circular.]

To make a time machine, construct a wormhole, say on Earth, with two ends A and B close together.  Now, take end B on a trip to the stars (anywhere will do) travelling close to the speed of light for, say, 100 years, but with B only experiencing 10 years.  Then, bring end B back to Earth.   Time connects differently through the wormhole than outside it.  If you now enter end B, you will exit end A 90 years ago!

This might not be possible.  Some predict that quantum effects would result in destruction of a time machine just before it's possible to use it.  But it's a fun idea.

Thursday, 29 August 2013

Gravity is the creator

Life on Earth doesn't continue just because the Sun provides energy.  What the Sun provides as well is something vital for life on the surface of our world - low entropy.  What this means is that the Sun provides energy in a highly ordered form - it's directional and it's limited to certain wavelengths.  Life uses the order in this energy source to build itself and keep itself going, all the while releasing energy as random heat.  Although life is very ordered - low entropy - life can continue because life is a source of disorder - high entropy as a result of life actually living.

So, having established that the Sun is a vital source of ordered energy, where did this order, this low entropy, come from?  It had to come from somewhere, because the universe shortly after the Big Bang consisted of widely and evenly spread out gas.  The answer is that the order in the Sun came from gravity.  Gravity is a long-range cumulative force, and gravity magnified differences in the gas: where there was slightly more gas even more would be pulled together.  This concentration of matter produced galaxies and stars.

However, gravity doesn't produce order from nothing.  Collapsing gas generates heat, and so the Second Law of Thermodynamics still applies - overall, the entropy of the universe increased - it's just that with gravity very localised spots with much lower entropy could form - stars and planets.

The source of life's complexity, the reason why life can appear and grow and evolve isn't anything strange or mysterious - it's the same force that fires up the nuclear furnaces at the heart of stars.

Wednesday, 28 August 2013

Zara's wager

There is this argument for justifying belief in God which is called 'Pascal's Wager'.  It goes like this:  If you believe in God and you are wrong, all you have lost is a lifetime of belief, but if you don't believe in God and you are wrong, you get an eternity in Hell for being an unbeliever.

This, as you might think, is flawed.  One reason it's flawed is that it's hard or even impossible to choose to believe.  You can't pretend to believe.  Another reason is that there are just so many gods - which do you believe in?

I have a modest proposal, a suggestion which I shall humbly call 'Zara's Wager'.  It goes like this:  If you believe in the wrong god, you are going to Hell.  If you don't believe and there is a god you are going to Hell.  So, it looks like you are going to Hell if there is a god.  Best make the best of it.  How?  Believe in Satan.  You might not be able to convince yourself that Satan exists, but the Devil is the Prince of Lies, and your hypocrisy will surely be appreciated.  You might believe in the wrong Devil, but again, I'm sure Satan will appreciate this, as unlike God, scripture doesn't say he is jealous.   So, do your best to get on good terms with the landlord of where you are going.  You don't have to do evil - a deathbed conversion will do the trick, a winning sign of laziness and inconsistency.

Beat that, Pascal!

Tuesday, 27 August 2013

What is Special Relativity?

Special relativity is an incredibly simple model of physics that leads to very strange (to us) conclusions.
Relativity was nothing new when Einstein published his first paper on Special Relativity.  Centuries before, Galileo had realised that motion made sense only as being relative to something else.  For example, a ball could be thrown and caught easily within a ship even if that ship was sailing at speed.

What Einstein did was to add to relative motion the idea of a limiting speed, which would be the same for everyone no matter how fast they were moving.  The idea of this limiting speed came from the work in the 1800's on electromagnetism, as there was a constant relating electric charges to magnetic forces, and that constant involved the speed of electromagnetic waves - the speed of light.

Einstein insisted that electromagnetism (and everything else about physics) should work the same no matter how fast you are moving relative to anything else - you should not be able to perform an experiment to determine some absolute speed at which you were moving.

So, if the speed of light was the same for everyone, what would be the result?  It would be that speeds would not add up simply.  If someone travelling at 20km/h turned on a torch and projected the beam of light ahead, both that person, and someone stationary relative to that person, should measure the speed of the beam as the speed of light (not the speed of light + 20km/h).   A vast number of experiments show that this is the case.  Other effects would be that lengths of objects moving close to the speed of light will appear shortened, and time should appear to move more slowly for such objects.  These effects have all been measured.

What with everything changing depending on speed, is there something that everyone will agree on?  Yes, there is - it is called the 'spacetime interval' between two events.  You may remember that the distance between two points A and B in space is given by sqrt((Ax - Bx)2 + (Ay - By)2 + (Az - Bz)2): the square root of the squares of the distances along three axes between A and B.

Special Relativity deals with points in 'spacetime' - the 4-dimensional combination of space and time (known as 'Minkowski space').  However, Relativity also has to deal with time being a different kind of dimension than those of space.  This difference results in changes of signs.  The equivalent of distance in Minkowski space is the 'spacetime interval' s, and it's calculated like this

s = sqrt((Ax - Bx)2 + (Ay - By)2 + (Az - Bz)2 - c2(At- Bt)2 )

It's the normal Pythagorean calculation, but with the difference in time squared multiplied by the square of the speed of light subtracted.

A speed (the speed of light) comes into the equation because it converts the units of time to units of distance.

No matter how something is moving, all observers will get the same value of 's' for that thing.  That's what stays the same in Einstein's Special Relativity.

By the way, you might be wondering what happens if the term involving times gets bigger that the sum of the terms involving space, giving a negative number to be square rooted.  This gives a perfectly acceptable 'imaginary number'.  'imaginary' spacetime intervals connect events which can be causally connected - one event could possibly be the cause of another.  Non-imaginary intervals are between events which cannot be causally linked, as faster-than-light speeds would be needed to get from one event to the other.

Sunday, 25 August 2013

You can go faster than the speed of light

You can go faster than the speed of light.  This seems to be a strange thing to claim, because isn't the speed of light the ultimate speed limit?  It is, but speed only makes sense as relative to something else, and during an actual journey.  It's possible to have travelled faster than light, but only in a very special way.

Imagine you are setting off to the centre of the galaxy, about 30,000 light years away, and you have no limit to the amount of fuel you can use.  Suppose you travel with an acceleration of 1g to make it comfortable on your spaceship.  You could reach the centre of our galaxy in 20 years.  That's an average of 1,500 times the speed of light.

But no-one will actually see you travel at this speed because they will see you take about 30,000 years to reach the centre.  You won't see the distance to the centre of the galaxy as 30,000 light years as you are travelling because speed compresses length - it will appear very much shorter.  However, when you stop at the centre, you can, in hindsight, work out how far you have gone and how long it took.  You can travel faster than the speed of light so long as no-one sees you do it, not even you!

How relativity makes magnetism

An electric current creates a magnetic field.  That's been known for a long time, but when physics is taught this is one of those things which is just stated, which I find a shame because the explanation is both simple and amazing.

First, we have to accept the consequences of there being a universal speed of light, observed by anyone no matter how they are moving.  Given that, things that are seen to be moving relative to an observer will show various effects.  Firstly, time will appear to slow for these things.  Secondly, lengths in the moving objects will seem to be shorter in the direction of movement.  Thirdly, moving objects will seem heavier than when they are at rest.  What matters for magnetism is the second effect - the contraction of length.

Now, imagine two parallel wires, each with an electric current flowing in the same direction.   First, let's look from the point of view of the positive nucleii of atoms on one of the wires.  Electrons in the opposite wire will be seen to be moving, and because of this distances between them will seem to be shorter, and so there will appear to be an increased density of negative charge.  Now let's look from the point of view of the moving negative electrons in one of the wires.  Nucleii in a second, opposite wire will be seen to be moving (backwards relative to the electrons in the first wire), and so there will seem to be an increased density of positive charge.

The increased densities of charge because of relativistic length contraction results in an attraction between two wires carrying electric currents in the same direction.  This is what magnetism consists of - a very, very, very tiny excess of electrostatic forces.  It's small because the movement of electrons in an electric currents we use to generate magnetism is extremely small - it's typically measured in metres per hour.  (Electricity is the signal for electrons to start moving, and that can travel very quickly).  That we can make magnetism at all with our technology shows how incredibly strong electrostatic forces are.

Saturday, 24 August 2013

Dinosaurs did not go extinct

Dinosaurs were not wiped out at the end of the Cretaceous era when some asteroid or comet hit the Earth and the result send most species into extinction.  The reason why it used to be said that dinosaurs disappeared was because the relationship between dinosaurs and their descendants today was not well understood.  That changed years ago when it was discovered that a considerable number of dinosaur species that were though to look much like reptiles were, in fact, covered in feathers.  It's now thought that the majority of certain groups of dinosaurs were either feathered all over or were born feathered and lost that covering later in life.

The existence of very well-preserved fossilised feathers can allow us to do something that was thought to be forever impossible - to find out the likely colours of some dinosaurs.  This can be done because the colours of feathers can be due to their very fine structure.  As a result we can know that some early gliding dinosaurs (such as Microrapter) were a combination of yellows and browns.

More detailed analysis of fossils is showing us more about how the species we call 'birds' arose from, and although it's not sorted out fully, there is little doubt that birds are members of a group of dinosaurs called Maniraptora, which includes the fearsome Velociraptors.

The so-called 'dinosaur killer' collision did no such thing.  The celestial impact had a dramatic effect on life because what it killed across the world was animals above a certain size.  Large land animals could not hide from the fires and impact heat that spread across the world, and in the aftermath large animals could not survive on the limited food that would have been left.  What survived were small-bodied species - small reptiles, small mammals, and small dinosaurs, and the dinosaurs that happened to survive were a one group that we now call birds.

Friday, 23 August 2013

Do black holes mean that the universe is safe?

The universe isn't safe?  It's a frightening thought, but let me put your mind at rest, at least a bit.  According to some ideas about physics the universe could collapse into a different type of universe at any time.  This is astronomically unlikely to happen while humans are around, and it would not be all at once.  A tiny flicker of a quantum event at one point in space could start it off, and then it would spread at the speed of light.  However, the universe is extremely big and expanding at an accelerating rate.  If the collapse happens in a distant part of the universe it may never reach us.  But really, don't worry, it's so very, very unlikely to happen while anyone is around.

What could make it happen fast is having vast amounts of energy concentrated in one place, kicking space around enough to make it able to flip into a different state.  But, there isn't anywhere around in the universe where that kind of concentrated energy can be found.  Or is there?

Black holes are only black because we aren't close.  Very strange things happen at the edge of a black hole if you can get very close to that edge and hover there, or if you can observe very close to that edge from a distance - things will get very, very hot, if current theories are right.  All the information associated with whatever falls into the black hole appears as thermalised radiation at the event horizon, and that radiation is very hot indeed, perhaps the hottest thing possible in our universe.

And so, if theories are true about black holes, it may be that close to their surfaces space is blasted with such intense heat that if it was going to collapse, it would have, and there are so many black holes around us that the universe should have been destroyed.

Perhaps the intense heat of black holes means we are safe from any possible collapse of the universe, no matter how incredibly unlikely!

Thursday, 22 August 2013

Relativity: why time slows with increased speed and with gravity

What I'm going to do is explain a way of looking at relativity that should give a feel for what is going on.   Some physicists may cringe at what I am going to write, but I have no shame!

First, let's take a look at Special Relativity.  Einstein realised that there was a speed that was constant for everyone, no matter what they are doing.  That speed is the speed of light.  The constant isn't defined by what light does, but it is the ultimate speed, and light goes at that speed in empty space, as does anything massless.  One way to look at why this speed is a constant is to consider it as the universal speed, the speed at which everything moves.  This makes no sense until we think of the speed as being in 4 dimensions, with time as one of those dimensions.  When something appears to be standing still (relative to you) in space it will not seem to be slowed in time.  The reason is that something standing still (relative to you) in space is moving at the ultimate speed, but only through time.  If something is moving relative to you, you will see its time slowed down.  The reason is that that thing is now moving through space as well as time, so some of its speed through time has been diverted to speed through space.  What happens as things speed up and slow down is that they are merely changing direction in the four dimensions of space and time; they aren't actually changing speed at all.

If something moves at the ultimate speed through space, as light does, it has no speed through time at all, and so its clocks (if it has any) appear stopped.

Now, General Relativity.  Imagine you are sitting alone in the dark, and you turn on a light.  A sphere of light will rush away from you in all directions, and (obviously) at the speed of light.  If you are weightless, floating in empty space, then that sphere of light will stay centred on you, as it speeds towards the stars.  That sphere of light will always be the furthest anything could have possibly moved away from you, because nothing can outrun light.

Gravity bends space and time.  If you are on the surface of a planet, in the dark, and you turn on a light, a sphere-like shape of light will rush away from you, but it won't remain centred on you.  Gravity drags down even light.  The centre of that globe of light will drift, just a tiny bit, down towards the centre of the planet.  If you were close to a very, very massive object such as a neutron star or black hole then the shape of the globe of light coming from you would be very distorted indeed.

The bending of space and time does this:  it's constantly telling things that they should be somewhere else.  The gravity of the Earth is nagging at your atoms, insisting that they really should be lower down.  The surface of the Earth pushes back up on your body and your house, car and furniture, to make sure you don't fall downwards, but that nagging continues which is why you feel gravity as a force.

Remember from Special Relativity that everything moves at the ultimate speed through space and time.  What gravity does can be though of as constantly moving space, and it's that movement of space that is telling your atoms that they should move.  Because your atoms are experiencing a movement of space, they can't be moving at the ultimate speed through time any more.  So, gravity's effect on space results in things being seen slowed down from a point of view where gravity is less.

At the edge of a black hole (the event horizon), we can consider that space is moving towards the centre of the hole at the speed of light.  This has two effects.  Firstly, than nothing can experience being stationary there, and secondly, time dilation will be infinite - clocks will appear stopped.

Everything moves at the universal speed, and gravity makes space move - that's an easy way to get some idea of how Special and General Relativity work.

Wednesday, 21 August 2013

Origins, explanations, and anti-explanations

Some really interesting questions have been asked on Twitter about what is reasonable and unreasonable when it comes to the origin of our universe.

One question is about what is likely and unlikely.  It may be that origins of universes are unlikely, but does that matter when we are dealing with origins?  There are ideas about the physics of the origin of our universe that can help us think about this.  The physicist Sean Carroll suggests (in his book From Eternity to Here) that our universe may be the result of a quantum fluctuation in an earlier universe.  That quantum fluctuation may have been astronomically unlikely, but that earlier universe may have got into a boring static state and have been around for trillions of trillions of years, and given enough time, the most unlikely things will happen.

Related to likelihood is the matter of complexity.  The reason is that complex things are hugely less likely to appear out of nothing than simple things, because there are so many random possibilities of which the complex things are a tiny fraction.  It's physically possible for a clock to appear out of nothingness by quantum fluctuations, but that is vastly less likely to happen than for an atom to appear out of nothingness.

Then there is the question of what we mean by 'explanation'. This is also linked to likelihood and complexity.  Evolution shows how apparently unlikely complex organisms can arise from much, much simpler systems through simple processes.  There is no 'conservation of complexity' in the universe - complexity can grow (and shrink).

What we mean by explanation is to try and find a simple and likely reason for something happening.   Our explanations may be wrong, but simplicity and likelihood are the criteria we use when we look for explanations.  This is why gods are not good at all as explanations - indeed they are 'anti-explanations', as introducing a god leaves more to explain that we started with.

Tuesday, 20 August 2013

Complex creators

Without wanting to wander too much into theism, I want to explore a common idea and show how it can be easily shown to be wrong, no matter what your belief system.  This idea is that a creator can be simple.  Some sort of vague mindless creative influence might possibility be simple, but a creator with a mind absolutely cannot.  Why?  Because of the things we insist a mind can do.  A mind can think, it can respond, it can remember, and it can change.  These things that a mind can do necessarily involve complexity.

Let's consider memory.  Memory requires storage of things separately so that they aren't confused - if you have a memory of red, and a memory of blue, then recalling these memories will recall each separately, and not some purple mess of combination.  There are many, many ways of storing such things, but method doesn't matter, what matters is that by any measure of complexity being able to remember has to involve complexity, such as the ability to assign storage to memories and later recall them based on some form of identification (such as the word "red" for the colour red).

Similar arguments for the requirement of complexity apply to the process of thinking, the changing of mind, the making of decisions.  All these things involve a mind changing states, and the existence of such states is part of what we call complexity.

The problem of complexity can't be avoided by labelling a creator 'supernatural', because in the above discussion no mention of physics has been made.  A 'supernatural' being has the same necessity for memory and thinking, no matter that the mechanism is forever unknowable.

Mind is complex, and if mind seems so complex that it surely needed a creator, then the mind of a creator is then so complex that a further creator is needed, and so on forever.  This is why the idea of a creator is never a satisfactory explanation for the existence of mind.

Monday, 19 August 2013

I'm fan of Roger Penrose

One of the greatest physicists, and still active in research in his 80s, is Roger Penrose.  Penrose has been working mostly behind the scenes for a long time, never having got the exposure of his friend and collaborator Stephen Hawking, and yet Penrose is at least Hawking's equal.  

When the theory behind black holes were being examined in the 60s and 70s, there were still many questions about what happened inside them (there still are), and one of those questions was whether or not anything that fell into a black hole could ever miss being crushed to destruction at the centre of the hole.  Penrose showed that no object could ever miss the centre of a simple black hole, and he did it using not physics but topological mathematics, a stunning achievement.  Penrose is one of those who revolutionised our understanding of these strange collapsed stars.

Penrose seems to like sometimes standing on the sidelines of physics, challenging established ideas and coming up with amazing new ways of looking at reality.  One of his challenges to such ideas is his rejection of the idea of inflation, the idea that the universe expanded incredibly fast right at its origin.  This expansion is supposed to have smoothed out the universe, creating a state of very low entropy, from which the universe we see around us could have formed.  Penrose says that inflation solves little, as inflation itself requires such special conditions that it's more unlikely than the smoothness it's supposed to explain.  Instead, Penrose has come up with some fascinating ideas of what the universe may have started like and what it may end up like, as discussed in his latest book "Cycles of Time".  As the physicist Lee Smolin says, only Penrose could write phrases like "after eternity" and really mean it!

Penrose does have some strange ideas, such as that minds can do things that computers can't, or that consciousness may be a quantum phenomenon.  However, he does have the honesty to admit in his writings that his views aren't mainstream.  I find that honesty both endearing and important.

His books can be dense with information, and hard to get through, but if you can, it's really worth it.  You will always learn something new, and get an exciting perspective on physics from one of the greats.

Saturday, 17 August 2013

Forget Mars - go to Titan!

I can remember the feeling of excitement I felt when the Huygens probe touched down on the surface of Titan, the biggest moon of Saturn.  Suddenly, we saw a landscape: shades of pale orange, rounded boulders scattered here and there.  So much more data came back from this mission, but the image of the rounded boulders told us so much.  Rounded meant eroded, rocks tumbling in a river, ground down by collisions.  This could have been an Earth landscape if not for the orange light, and the temperature.  The rocks were not the familiar minerals of Earth, but ice - water ice frozen into hardness.  The river that tossed the rocks around was not one of water, but methane.

So much of Titan looks familiar.  Mountains, rivers, seas, volcanoes,  dry land with dunes.  Titan was a stage on which the same stories where told but with different players.  Mountains of ice, rivers of hydrocarbons, volcanoes from which water/ammonia lava flowed.  This is becoming a familiar story - cold doesn't seem to be a barrier to interesting and beautiful things happening: Freezing Neptune has the strongest winds of anywhere in the Solar System!

Does the similarity with Earth stop with landscapes?  Does the existence of water lava mean that there might be life?  Perhaps.  Titan is literally dripping with complex chemistry, as energy from the distant sun reacts with Titan's atmosphere.  It's definitely worth looking.

There is another advantage to Titan for humans.  Strange as it may seem, it could be a great place for a colony.  Titan has an atmosphere - not thick enough to be harmful to people, but thick enough to mean that humans could walk on Titan's surface without space suits.  Heated clothing would be vital, but all that would be needed to breathe would be an oxygen mask.  The atmosphere would protect against cosmic and solar radiation.  Titan has all the resources a colony would need - plenty of water as ice and vast amounts of hydrocarbons to make food and fuel.

There is no other place away from our planet that we could walk in the 'open air', without fear of radiation or decompression.  And just think of the views of Saturn!

Friday, 16 August 2013

What possible evidence can there be for gods?

I see that some rationalist non-believers (such as Jerry Coyne) say that unlike some other rationalist non-believers (such as PZ Myers), they believe that there can be evidence for the existence of gods.  I'm really trying to understand this position, because it seems to me that the supposed nature of gods necessarily includes attributes that are beyond any evidence, ensuring that there is a vast difference between an enormously powerful being who can manipulate the world and a god.

Some of the attributes that may be assigned to gods are:

1. Being an avatar in some way of Nature - Poseidon isn't just good at making storms, he the personification of the sea.   Poseidon and seas are somehow bound together.

2. Being the source of what otherwise would be an abstraction - Yahweh is the source of morality, not just a good being.  Some say Yahweh is the reason for mathematics working.

3. Having creative power.  A god may not be a being within Nature, but may instead be the source of Nature, in some sort of 'ground of being' way.

4. Having magic abilities - being able to work miracles.

I'm at a loss to understand how any of these attributes can be supported by evidence.  A powerful being might be able to do very dramatic things, and might say that they are the source of morality and logic, but there is no way I can see that such claims can in any way be demonstrated by evidence.

This matters, because the difference between a hugely powerful being and a god is that in religion a god gets to define what is right and wrong, and people live their lives accordingly.

I can see how there might be evidence that a powerful being performed various acts that were interpreted as miracles by the authors of holy books.  But that still doesn't get us to that being having the kind of moral authority that should influence lives.  Godhood matters, and yet it seems to be that godhood is clearly beyond any possibility of demonstration by evidence.

Thursday, 15 August 2013

10 reasons not to be a dick

In 2010 Phil Plait gave his now famous "Don't be a dick" speech at The Amazing Meeting.  I thought it was silly, and that people should not need to calm down about matters that were important to them, matters of fact and reason and fairness.  But since that time I have realised Plait's wisdom.  "Don't be a dick" is good advice, for many reasons:

1. Being a dick is tiring.  It really is.  Emotional reactions can run out of steam and it can take a lot of effort to maintain the full dick persona.

2. Most people aren't very good at being a dick.  Being snarky and satirical can sometimes be effective but only if done really well.  When not done well you will come across simply as dickishly mean and spiteful.

3. Not being a dick is a good debating tactic, gaining you support, especially if your opponent is definitely being dickish.

4. Not being  dick can actually unsettle an opponent, particularly if they have usually had to deal with dicks.  It gives you an advantage.

5. Not being a dick leads to calmer thinking, allowing you to respond more thoughtfully and effectively in discussions and debates.

6. You are going to be wrong about something - it happens to everyone.  If you are wrong while being a dick you will be thought of as having been an ass.  Better to be wrong while not being a dick, because it only takes a few words to correct yourself in a way that others will think better of you for changing your mind.

7. Being a dick is unimaginative - it limits how you can approach an issue, and can paint you into a corner.

8. Being a dick isn't always easy.  You may think you are being a dick but no-one may actually notice.  That's hugely embarrassing.

9. You will feel better about yourself.  You really won't want to look back at dickish you in a few years time.  You don't want to fill your life with awkward memories.

10. The "don't be a dick" meme is supported by Wil Wheaton.  You want to be like Wil Wheaton, don't you?

Unless you are sure you are the next Oscar Wilde or Dorothy Parker, just don't be a dick - even if you like the idea, leave it to the few who are good at it.  

Science can be sure of many things

Science does keep changing, what with Newton's ideas being replaces by those of Einstein, and quantum mechanics messing up simple ideas of what matter was made of.  But not really.  This isn't the way science works.

Science involves two things which are combined to try and help understand reality:  the first is an hypothesis, an idea about what is happening and the second is data.  What is seen to happen - the data - is used to test ideas about what is actually happening.  Science keeps progressing in terms of what is seen to happen, and once enough reliable data has been gathered what is seen to happen rarely changes, whereas ideas about what is actually happening can often change.

For example, in the study of genetics and inheritance data about the way inherited characteristics behave has been known for a long time.  It has been known that the basis of inheritance has to be digital, not continuous, because individual characteristics don't blend, they retain their existence from generation to generation: this is why features present a grandparent can re-appear in grandchildren while not visible in the children of the grandparents: a feature can require two copies of inheritance material to be visible.  This feature can be only present in one copy in the first generation, but two copies can randomly come together in the second generation. We know based on data that genetic material in humans is paired up in most cells, and that it contains digital information.

There were all kinds of hypotheses about what the genetic material consisted off, and eventually even more data showed that it was DNA.  Once found, DNA became a new part of the data, part of the known.  It's a fact about human existence: science isn't going to find humans that don't have DNA.

Another example is gravity.  Newton's model of gravity was based on data about planetary (and other) movement.  We knew that the Earth orbited the Sun at that time.   More precise data was one of the things that led to Einstein's model of gravity, but that was never going to show that the Earth did not orbit the Sun.

Science does progress, and does lead to things that it is entirely reasonable for us to consider true and not provisional.  What changes in science is the understanding of mechanism, of what is happening behind the scenes.  In 1000 years we will still be saying that the Earth orbits the Sun (unless we have moved the Earth!).    

Tuesday, 13 August 2013

"Quine" and Consciousness

A friend, who is known online as "Quine", posted this link to a blog post of his about consciousness.  It's really worth reading.

Quine has provided me with some really useful ways to think about consciousness, especially in response to those who who insist that there must be some non-physical aspect, such as that consciousness develops, both through evolution and in the life of an animal.  There is a point where growth and organisation of the brain allows for some consciousness, and that is certainly a physical change of state.