Tuesday, July 7, 2009

Steven Pinker, Evolution and the Mind

In this post and this post I've discussed the theory of the mind as a model-maker, and how evolutionary theory is commonly used to bridge the models from the mind into reality. Here is Steven Pinker's version of this move from The Blank Slate:
"Modernism and postmodernism cling to a theory of perception that was rejected long ago; that the sense organs present the brain with a tableau of raw colors and sounds and that everything else in perceptual experience is a learned social construction. As we saw in preceding chapters, the visual system of the brain comprises some fifty regions that take raw pixels and effortlessly organize them into surfaces, colors, motions, and three-dimensional objects. We can no more turn the system off and get immediate access to pure sensory experience than we can override our stomachs and tell them when to release their digestive enzymes. The visual system, moreover, does not drug us into a hallucinatory fantasy disconnected from the real world. It evolved to feed us information about the consequential things out there, like rocks, cliffs, animals, and other people and their intentions." (p. 412)
This example has it all. It's got the half-baked Kantianism masquerading as modern scientific insight; the confident assertion of evolutionary theory as the true savior from Descartes' Evil Demon (the hallucinatory fantasy by its original name); and the overall confident tone that modern scientists have those pesky old philosophical problems well in hand.

Pinker gives us the impression that the theory that the senses give us a tableau of raw colors and sounds was disproved by science - that's what the talk about fifty brain regions and pixels is about. Actually, this theory was blown away back in the 18th century by Kant, and Kant didn't need any neuroscience to do it. He also went a lot deeper than Pinker has gone. It's not just that our perceptual experience comes already organized into surfaces, colors and three-dimensional objects. Our entire mental life comes already organized into the basic categories of cognition; the here, there, before, after, unity, multiplicity, more, less, etc. The scientist may be able to "get behind" the perceptual experience of his lab subject, but he will never get behind the cognitive categories of his own thought. Those categories either map directly onto reality or they don't; if they don't, then science - including evolutionary science - isn't possible, at least if we want a science of the noumenal and not merely the phenomenal. If they do map onto reality, then evolution isn't needed to bootstrap the mind. Either way, the appeal to evolution is at best a distraction from the true issue.

The more I read about evolution, the more awe-inspiring it becomes. Alone among scientific theories, it seems, it is not only proven by science, but itself proves the science that already proved it. 

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