Monday, 22 June 2015

A response to Donald Hoffman's TED talk.

I have been following Hoffman's work for many years, thanks to a mutual friend.

A fascinating talk (I admire good public speakers), but I disagree with his conclusions. Evolution does give accurate perceptions, but only accurate enough. Evolution is rarely wasteful. The example of the beetle getting confused about bottles was a bad one, because evolution had not been allowed to act. Given a few thousand years, the beetle would almost certainly have evolved to distinguish between female and beer bottle. If you are going to assess evolution's power to improve accuracy you have to wait for an evolutionary time scale. The beetle's vision isn't telling it where females are - after all, beetles have no concept of females! If you assume that this was what the beetle's vision was trying to do then of course you will come to the assumption that it is wildly inaccurate. The beetle's vision was only showing is what it would have to see to mate, and that had been very accurate for millions of years. The appropriate measure of accuracy is between what we experience and what we believe we experience. 

We have pretty accurate vision. The tomato really is in front of us. We throw that because we can objectively measure how far a hand has to move to reach it. Apes can accurately assess what other apes can see so that they can hide food. That hiding involves objectively accurate assessments of lines of sight. 

Of course, our vision is only accurate to a limit. We can't see the tomato's cells or its quarks. But that doesn't mean we are mistaken in chopping it up and putting it in sandwiches.


Vikas Pandey said...

How do u define " we" by the way

Fred Melden said...

Of course “If you are going to assess evolution's power to improve accuracy you have to wait for an evolutionary time scale”. That was NOT Dr. Hoffmann’s point. The point is that evolution prepares us for efficiency - to recognize what we need to with minimal cost. Icons are efficient – fewer neurons required to spot bumps than evaluate the rest of the bumpy object. Such evaluation would require more neurons, which require beaucoup energy and add weight. This cost in food requirements and decreased mobility outweighs the benefits – at least until man comes along and starts making bumpy bottles. Given enough time, the beetle will either go extinct or adapt, but the latter would probably involve adding another icon – perhaps check for antennae too. Dr. Hoffmann was NOT saying the beetle was “wildly inaccurate”. He was saying the beetle was accurate in locating the icon (i.e., the bumps), and that evolution had made the significator for reproduction.

Again, Hoffmann would not say the tomato wasn’t there in front of us. This is not a debate about the existence of objects, but our perceptions. The female beetle, as you say, is not part of the male beetle’s concepts. (Actually, nothing is.) Our mammalian brains are more complex, which allows us the advantage of social groups – with their own evolutionary advantages; and also the luxury of forming concepts. Apes can “accurately assess” the states and conditions of other apes, which is a requirement for an effective social group – an evolutionary advantage. But the tomato was considered poisonous for 200 years in Europe – an inaccurate assessment.

And BTW, our vision is NOT “pretty accurate”. Its spectrum is narrow, and resolution much less than birds of prey. And our other senses are equally limited.

Steve Zara said...

Thank you for your comment.

When I talk about evolution and accuracy, I don't mean that the bottle-attracted beetle will come to know about bottles. What I mean is that it will evolve to better locate what to mate with. There are no 'icons' involved, as the beetle has no mind for representations - it will be instinctive behaviour. My point is that evolution can and does result in correct (though possibly mindless) interpretations of reality, but for most animals that interpretation can't adapt minute-by-minute. You can't validate the correctness of evolved senses by throwing in something that has only been around for a few thousand years.

As for Hoffman questioning perceptions not reality, my understanding of his work over many years is that he really is questioning reality, in that what we perceive to be real is actually only a small subset of what is really going on.

I have to disagree about human vision. When I say it's good, I don't mean we are brilliant at hunting small mammals at night - what I mean is that we use most of the spectrum of radiation that comes through the atmosphere to build a reasonably complete model of the word we live in. We don't bump into trees and we can recognise tigers. We aren't bumbling around. We know that our vision is accurate because we build scientific tools to extend our senses and they report that when we think we see a tomato, it really is a tomato. It's not a bottle.

Fred Melden said...

Yes, he might “evolve to better locate what to mate with.” But that ability is unlikely to be based on perceiving actual reality. Assuming that improved ability comes to pass, it will be based on perceptions of a slightly more expanded set of icons. Evolution prepares a species to perceive as much of reality it needs to survive and propagate. Hoffmann’s proposition connects with Kant’s argument about phenomena vs. noumena. Kant was not wrong in this; nor is Hoffmann wrong. We DO bump into trees at night; but the bat does not. The bat does not perceive the actual tree – only the sound reflecting off it in a particular way. We do not perceive the actual tree – only the image of its outer bark and leaves (and fruit and flowers if it possesses these), and the tactile impressions we gain from it. Science has taught us about the structure of the tree, about its phloem, etc. But these are not direct perceptions.

Neither Hoffman nor I are arguing about the inadequacy of evolution; only about the shortcuts it takes to achieve its end results. Those results do not require accurate perception of reality – only ‘good enough’ (GE). The GE approach is more efficient, requires less energy, works faster, evolves more quickly, etc., etc. GE does not require us to perceive that the Earth rotates (rather than the sun and stars circling us), and so we apply the latter interpretation. Similarly, the dolphin does not perceive the whole shark – organs, emotions, physiology, etc. – but only what it needs to survive: “Bad guy with big teeth coming!” Talk to a diver who loves sharks, and you’ll discover a totally different perception of them (one opposite my own).

A human example of the difference between icon and reality would be arithmetic vs mathematics. Both are abstract, but one is derived from direct observation; the other is conceptualized only after the limitations of the first become evident in our attempts to describe the world. Only then do we reach irrational numbers and transcendental numbers (Feigenbaum’s Constant, Planck’s Constant, etc.), calculus and quantum physics. These describe actual reality – which is the reality we CANNOT perceive. We only perceive the icons of that reality – the glow of the heated ember, for instance, or the light from the stars.

Finally, yes, a tomato is a tomato. ‘Gork sees tomato. Tomato is food. Gork eats tomato.’ That’s all he needs to know. A perfect example of GE.