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12. Knowledge Sources / B. Perception / 7. Causal Perception

[perception as a causal chain from world to mind]

10 ideas
I prefer the causal theory to sense data, because sensations are events, not apprehensions [Ross]
     Full Idea: The sensum-theory seems to me less probable than a causal theory of perception, which regards sensuous experience as not being apprehension at all, but a set of mental events produced by external bodies on our bodies and minds.
     From: W. David Ross (The Right and the Good [1930], §IV)
     A reaction: The point is that there is no third item between the object and the mind, which has to be 'apprehended'. Sense-data give a good account of delusions (where we apprehend the 'data', but not the real object). I think I agree with Ross.
Causal and representative theories of perception are wrong as they refer to unobservables [Ayer]
     Full Idea: The fact that all causal and representative theories of perception treat material things as if they were unobservable entities entitles us to rule them out a priori.
     From: A.J. Ayer (Language,Truth and Logic [1936], Ch.2)
     A reaction: It seems to me that we can accept a causal/representative account of perception if we think of it in terms of 'best explanation' rather than observables. Explanation requires speculation, which logical positivists can't cope with.
Maybe experience is not essential to perception, but only to the causing of beliefs [Armstrong, by Scruton]
     Full Idea: Armstrong has argued that experience, as normally understood, is not necessary to perception. To perceive is to acquire beliefs, through a causal process.
     From: report of David M. Armstrong (Belief Truth and Knowledge [1973]) by Roger Scruton - Modern Philosophy:introduction and survey 23.4
Appearances don't guarantee reality, unless the appearance is actually caused by the reality [Dancy,J]
     Full Idea: If I stare at a white wall with my brain wired to a virtual reality computer, and it generates a white wall, we wouldn't say I am seeing reality. It seems that the wall itself must in some way cause my perception of it.
     From: Jonathan Dancy (Intro to Contemporary Epistemology [1985], 11.4)
     A reaction: But suppose the computer generated in my mind an image of the wall which was actually in front of me? And suppose the computer got its image from the identical wall next door, not from mine? And it was only judged identical because the architect said so
Perceptual beliefs may be directly caused, but generalisations can't be [Dancy,J]
     Full Idea: A perceptual belief that p can have as its main cause the fact that p. More general facts (all men are mortal; e=mc2) cannot be the main cause of my belief, even if they do function causally in some way.
     From: Jonathan Dancy (Intro to Contemporary Epistemology [1985], 11.5)
     A reaction: Note that the perceptual belief can be the "main" cause; it seems to me that most beliefs are caused by judgements, though I may normally accept beliefs which are directly caused by perception, if I have no reason to challenge them.
Perceptual concepts can't just refer to what causes classification [Papineau]
     Full Idea: We may say that a perceptual concept refers to that entity which normally causes classificatory uses of that concept...but this won't work because such deployments are often caused by things which the concept doesn't refer to. A model might cause 'bird'.
     From: David Papineau (Thinking about Consciousness [2002], 4.6)
     A reaction: This rejects the causal theory of perceptual concepts. I like the approach, because classifying things strikes me as absolutely basic to what brains do. To see that x is a bird is to place x in the class of birds.
Science requires a causal theory - perception of an object must be an experience caused by the object [Lowe]
     Full Idea: Only a causal theory of perception will respect the facts of physiology and physics ...meaning a theory which maintains that for a subject to perceive a physical object the subject should enjoy some appropriate perceptual experience caused by the object.
     From: E.J. Lowe (Locke on Human Understanding [1995], Ch.3)
     A reaction: If I hallucinate an object, then presumably I am not allowed to say that I 'perceive' it, but that seems to make the causal theory an idle tautology. If we are in virtual reality then there aren't any objects.
A causal theorist can be a direct realist, if all objects of perception are external [Lowe]
     Full Idea: A causal theorist can be a 'direct realist' in the sense that he can hold that the only objects of perception are external objects.
     From: E.J. Lowe (Introduction to the Philosophy of Mind [2000], Ch. 6)
     A reaction: There still seem to be problems with perceiving reflections, or very distant objects (the time-lag problem), or perceiving 'secondary' qualities.
If blindsight shows we don't need perceptual experiences, the causal theory is wrong [Lowe]
     Full Idea: If we don't need to have perceptual experiences in order to see things (as 'blindsight' might suggest), the causal theory of perception cannot be correct.
     From: E.J. Lowe (Introduction to the Philosophy of Mind [2000], Ch. 6)
     A reaction: This is because the causal theory implies a chain of events culminating in experience as the last stage. There is no suggestion, though, that unconscious perception would be non-causal, as it bypasses all the problems about consciousness.
Causal theory says true perceptions must be caused by the object perceived [Bernecker/Dretske]
     Full Idea: The causal theory of perceptions says that to perceive an object is to have a sense-datum caused by that object; it is not enough for the world to be the way we perceive it; the world must cause the perception.
     From: Bernecker / Dretske (Knowledge:Readings in Cont.Epist [2000], Pt.V Int)
     A reaction: All causal theories seem dubious to me; what causes something is not the same was what it means, or refers to, or what justifies it. The hallmark of successful perception is truth. I would perceive a tree if God planted the perception in me.