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?"