The argument above might suggest to some readers that perception is based on "assumptions" about the world. It would be a misleading idea for many reasons. For instance, to work by assuming something implies that one knows about or can imagine a more general situation which for the present purpose needs to be narrowed down. However, there is no reason why evolution (nor the resulting animal) should "know" anything about more general conditions. For the evolving animal its ecological niche is the universe. If a perceptual mechanism can pick up useful information in and about this universe, it is there to stay. The difficulties that we as scientists, trained in abstract geometry and theoretical physics, encounter in our attempts at understanding the preconditions for perception should not be ascribed to the perceptual system under study. (Runeson, 1977, p. 176).Take the claim that "to work by assuming something implies that one knows about or can imagine a more general situation which for the present purpose needs to be narrowed down". I don't see this implication. One might well hold the view that natural selection simply exterminated the visual systems without the right "assumptions". So, the visual system just has those assumptions, but not the ability to entertain alternatives. Indeed, a standard cognitivist assumption is that the assumptions might well be merely "implicit".
Nor does this account involve saying the evolution "knows" anything about more general conditions. That is only metaphorical at best.
The last sentences seems to me to be a little strong. I would say that "should not necessarily be ascribed to the perceptual system under study".
Assumptions are extra information which are used to resolve the various ambiguities of sensation-based perception. But given that perception is how we come to have knowledge about the world, if perception is ambiguous then where did the assumptions get their contents? On what basis did an organism come to have assumptions that reliably disambiguate an ambiguous sensation?
ReplyDeleteI know there's a lot of work going on using increasingly sophisticated maths (eg Bayesian statistics) to try and figure out ways a system might come to acquire the best prior probability distribution, etc. I admire the attempts to really tackle this hard problem, I just don't think the problem exists :) Plus even a top notch Bayesian prior is a probability distribution, which means it's success will be probabilistic.
It sounds like you are not jumping on the Runeson bandwagon here. To press the point, I would say that Runeson is offering a caricature of what evolution by natural selection requires for the evolution of mechanisms that make assumptions.
ReplyDeleteQuite the contrary; I was laying out more precisely what I take from "to work by assuming something implies that one knows about or can imagine a more general situation which for the present purpose needs to be narrowed down".
ReplyDeleteAssumptions can be wrong. Errors caused by assumptions driving perception could get you killed.
Ok. But, my reply has been that assuming that P does not imply that one knows or can image a more general situation. So, take the shark and the electric field. A cognitivist description might say that the shark detects F, then assumes that this means food. That does not imply that the shark knows that the field might not be that of food or that the shark imagines other things that could cause the field.
ReplyDeleteBut on what basis does the shark come to assume this means food?
ReplyDeleteEvolution by natural selection. Why is this any different for cognitivists than it is for EP?
ReplyDeleteNo, what's the informational basis? How does the assumption 'get in' to the system if it's not in the proximal stimulus?
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