The Case Against Reality

Donald Hoffman is a Professor of Cognitive Science at the University of California, Irvine. He is known for his studies in visual perception and optical illusion, as documented in his 1998 book Visual Intelligence: How We Create What We See, and at his webpage. These optical illusions got him interested in thinking about whether our visual perceptions are veridical at all.

Recently, The Atlantic magazine published an interview with Hoffman entitled “The Case Against Reality”. According to the article,

Hoffman has spent the past three decades studying perception, artificial intelligence, evolutionary game theory and the brain, and his conclusion is a dramatic one: The world presented to us by our perceptions is nothing like reality. What’s more, he says, we have evolution itself to thank for this magnificent illusion, as it maximizes evolutionary fitness by driving truth to extinction.

Hoffman explains his change toward this point of view in this 2008 piece, “What Have You Changed Your Mind About? Why?”:

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.

Hoffman argues for this conclusion in more rigorous fashion in his peer-reviewed article:

Justin T. Mark, Brian B. Marion, Donald D. Hoffman, “Natural selection and veridical perceptions,” Journal of Theoretical Biology 266 (2010) 504–515.

The abstract:

Does natural selection favor veridical perceptions, those that more accurately depict the objective environment? Students of perception often claim that it does. But this claim, though influential, has not been adequately tested. Here we formalize the claim and a few alternatives. To test them, we introduce ‘interface games,’ a class of evolutionary games in which perceptual strategies compete. We explore, in closed-form solutions and Monte Carlo simulations, some simpler games that assume frequency-dependent selection and complete mixing in infinite populations. We find that veridical perceptions can be driven to extinction by non-veridical strategies that are tuned to utility rather than objective reality. This suggests that natural selection need not favor veridical perceptions, and that the effects of selection on sensory perception deserve further study.

Interestingly enough, therefore, Hoffman seems to come to a conclusion similar to the one Alvin Plantinga argues in ch. 10 of Where the Conflict Really Lies: we should not expect — in the absence of further argument — that creatures formed by a naturalistic evolutionary process would have veridical perceptions. Hoffman is aware that he may be playing into Plantinga’s critique of naturalistic evolution as epistemologically self-defeating. In his most recent publication on the topic (Donald Hoffman and Chetan Prakash, “Objects of consciousness,” Frontiers in Psychology, published 17 June 2014), Hoffman responds to a criticism of his argument:

(9) You argue that natural selection does not favor true perceptions. But this entails that the reliability of our cognitive faculties is low or inscrutable, and therefore constitutes a defeater for belief in natural selection. See Alvin Plantinga’s argument on this (Plantinga, 2002).

Hoffman replies:

Evolutionary games and genetic algorithms demonstrate that natural selection does not, in general, favor true perceptions. But this entails nothing about the reliability of our cognitive faculties more generally. Indeed, selection pressures might favor more accurate logic and mathematics, since these are critical for the proper estimation of the fitness consequences of actions. The selection pressures on each cognitive faculty must be studied individually before conclusions about reliability are drawn.

But there are two problems with this reply. First, even if Hoffman’s argument were restricted to visual perception, and not to our cognitive faculties more generally (e.g., memory, introspection, a priori rational insight, testimonial belief, inferential reasoning, etc.), the conclusion that our visual perceptions would be wholly unreliable given natural selection would be sufficient for Plantinga’s conclusion of self-defeat. After all, reliance upon the veridicality of our visual perceptions was and always will be crucial for any scientific argument for the truth of evolution. So if these perceptions cannot be trusted, we have little reason to think evolutionary theory is true.

Second, it’s not clear that Hoffman’s application of evolutionary game theory is only specially applicable to visual perception, rather than being relevant for our cognitive faculties generally. If “we find that veridical perceptions can be driven to extinction by non-veridical strategies that are tuned to utility rather than objective reality” (2010, p. 504, my emphasis), then why wouldn’t veridical cognitive faculties (more generally) be driven to extinction by non-veridical strategies that are tuned to utility rather than objective reality? After all, evolutionary theory purports to be the true account of the formation of all of our cognitive faculties, not just our faculty of visual perception. If evolutionary game theory proves that “true perception generally goes extinct” when “animals that perceive the truth compete with others that sacrifice truth for speed and energy-efficiency” (2008), why wouldn’t there be a similar sacrifice with respect to other cognitive faculties? In fact, Hoffman regards the following theorem as now proven: “According to evolution by natural selection, an organism that sees reality as it is will never be more fit than an organism of equal complexity that sees none of reality but is just tuned to fitness” (Atlantic interview). But then wouldn’t it also be the case that an organism that cognizes reality as it is will never be more fit than an organism of equal complexity that cognizes none of reality but is just tuned to fitness? On the evolutionary story, every cognitive faculty we have was produced by a process that was tuned to fitness (rather than tuned to some other value, such as truth).