From Edge Questions, Donald Hoffman writes about how he changed his mind about perception:
Veridical Perception
I have changed my mind about the nature of perception. I thought that a goal of perception is to estimate properties of an objective physical world, and that perception is useful precisely to the extent that its estimates are veridical. After all, incorrect perceptions beget incorrect actions, and incorrect actions beget fewer offspring than correct actions. Hence, on evolutionary grounds, veridical perceptions should proliferate.
Although the image at the eye, for instance, contains insufficient information by itself to recover the true state of the world, natural selection has built into the visual system the correct prior assumptions about the world, and about how it projects onto our retinas, so that our visual estimates are, in general, veridical. And we can verify that this is the case, by deducing those prior assumptions from psychological experiments, and comparing them with the world. Vision scientists are now succeeding in this enterprise. But we need not wait for their final report to conclude with confidence that perception is veridical. All we need is the obvious rhetorical question: Of what possible use is non-veridical perception?
I now think that perception is useful because it is not veridical. The argument that evolution favors veridical perceptions is wrong, both theoretically and empirically. It is wrong in theory, because natural selection hinges on reproductive fitness, not on truth, and the two are not the same: Reproductive fitness in a particular niche might, for instance, be enhanced by reducing expenditures of time and energy in perception; true perceptions, in consequence, might be less fit than niche-specific shortcuts. It is wrong empirically: mimicry, camouflage, mating errors and supernormal stimuli are ubiquitous in nature, and all are predicated on non-veridical perceptions. The cockroach, we suspect, sees little of the truth, but is quite fit, though easily fooled, with its niche-specific perceptual hacks. Moreover, computational simulations based on evolutionary game theory, in which virtual animals that perceive the truth compete with others that sacrifice truth for speed and energy-efficiency, find that true perception generally goes extinct.
It used to be hard to imagine how perceptions could possibly be useful if they were not true. Now, thanks to technology, we have a metaphor that makes it clear — the windows interface of the personal computer. This interface sports colorful geometric icons on a two-dimensional screen. The colors, shapes and positions of the icons on the screen are not true depictions of what they represent inside the computer. And that is why the interface is useful. It hides the complexity of the diodes, resistors, voltages and magnetic fields inside the computer. It allows us to effectively interact with the truth because it hides the truth.
It
has not been easy for me to change my mind about the nature
of perception. The culprit, I think, is natural selection.
I have been shaped by it to take my perceptions seriously.
After all, those of our predecessors who did not, for instance,
take their tiger or viper or cliff perceptions seriously had
less chance of becoming our ancestors. It is apparently a small
step, though not a logical one, from taking perception seriously to taking it literally.
Unfortunately our ancestors faced no
selective pressures that would prevent them from conflating
the serious with the literal: One who takes the cliff both
seriously and literally avoids harms just as much as one who
takes the cliff seriously but not literally. Hence our collective
history of believing in flat earth, geocentric cosmology, and
veridical perception. I should very much like to join Samuel
Johnson in rejecting the claim that perception is not veridical,
by kicking a stone and exclaiming "I refute it thus." But even
as my foot ached from the ill-advised kick, I would still harbor
the skeptical thought, "Yes, you should have taken that
rock more seriously, but should you take it literally?"
oh boy, hours of fun and enjoyment could ensue right about now!
lets just take two good counterexamples for the "visual perception is useless if not veridical" hypothesis:
* dreams
* cinema
while we engage in profound visual perception in both these realms and glean great value from each, theres no need whatsoever for either to "represent" some "objective" truth/reality in order for the value to be present/conveyed.
of course this is much more general than just the realm of visual perception...
Posted by: neilalien | January 10, 2008 at 11:48 AM