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12. Knowledge Sources / B. Perception / 4. Sense Data / d. Sense-data problems

[difficulties with the concept of sense-data]

19 ideas
We cannot assume that the subject actually exists, so we cannot distinguish sensations from sense-data [Russell]
     Full Idea: If we are to avoid a perfectly gratuitous assumption, we must dispense with the subject as one of the actual ingredients of the world; but when we do this, the possibility of distinguishing the sensation from the sense-datum vanishes.
     From: Bertrand Russell (The Analysis of Mind [1921], Lec. VIII)
     A reaction: This is the reason why Russell himself rejected sense-data. It is more normal, I think, to reject them simply as being superfluous. If the subject can simply perceive the sense-data, why can't they just perceive the object more directly?
My 'acquaintance' with sense-data is nothing like my knowing New York [Williams,M on Russell]
     Full Idea: My 'acquaintance' with sense-data is nothing like my knowing New York.
     From: comment on Bertrand Russell (Knowledge by Acquaintance and Description-1 [1911]) by Michael Williams - Without Immediate Justification §4
     A reaction: This pinpoints a nice difficulty for Russell. Williams may misrepresent Russell's account of acquaintance, but that is probably because Russell is unclear, or uncertain. The problem is when Russell claims that his acquaintance gives knowledge.
Individuating sense-data is difficult, because they divide when closely attended to [Russell]
     Full Idea: There is some difficulty in deciding what is to be considered one sense-datum: often attention causes divisions to appear where, so far as can be discovered, there were no divisions before.
     From: Bertrand Russell (The Relation of Sense-Data to Physics [1914], §II)
     A reaction: This was, I suspect, why Russell had dropped the idea of sense-data by 1921. He does, however, say that they are the last unit in analysis, rather than being the most basic unit of perception. In other words, they are purely theoretical.
Sense-data may be subjective, if closing our eyes can change them [Russell]
     Full Idea: One reason often alleged for the subjectivity of sense-data is that the appearance of a thing itself may change when we find it hard to suppose that the thing itself has changed - as when we shut our eyes, or screw them up to make things look double.
     From: Bertrand Russell (The Relation of Sense-Data to Physics [1914], §VIII)
     A reaction: Russell firmly denies that they are subjective. These examples are also said to support to proposed existence of sense-data in the first place, since they show the gap between appearance and reality.
There are no raw sense-data - our experiences are of the sound or colour of something [Heidegger]
     Full Idea: We always take a noise as the sound of something; we always take a hue as the color of something. We simply do not experience raw, uninterpreted sense-data - these are the inventions of philosophers.
     From: Martin Heidegger (Being and Time [1927], 207/163-4), quoted by Richard Polt - Heidegger: an introduction 3.§31-3
     A reaction: This is something like the modern view of sense-data as promoted by John McDowell, rather than the experiential atoms of Russell and Moore. Experience is holistic, but that doesn't mean we can't analyse it into components.
Part of what we mean by stating the facts is the way we tend to experience them [Wittgenstein]
     Full Idea: There is no need of a theory to reconcile what we know about sense data and what we believe about physical objects, because part of what we mean by saying that a penny is round is that we see it as elliptical in such and such conditions.
     From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], C III)
     A reaction: This is an interesting and cunning move to bridge the gap between our representations and reallity. We may surmise how a thing really is, but then be surprised by the sense-data we get from it.
As sense-data are necessarily private, they are attacked by Wittgenstein's objections [Wittgenstein, by Robinson,H]
     Full Idea: Sense-data are usually conceived as necessarily private to individual observers, so the final crisis for the empiricist conception of perception was Wittgenstein's famous polemic against such private objects.
     From: report of Ludwig Wittgenstein (Philosophical Investigations [1952]) by Howard Robinson - Perception IV.1
     A reaction: Personally I remain unconvinced by Wittgenstein's very elusive argument, but I think there are plenty of other reasons for doubting whether the idea of sense-data throws much light on our understanding of the processes of perception.
We are not conscious of pure liquidity, but of the liquidity of water [Firth]
     Full Idea: We are not conscious of liquidity, coldness, and solidity, but of the liquidity of water, the coldness of ice, and the solidity of rocks.
     From: Roderick Firth (Sense Data and the Percept Theory [1949]), quoted by Howard Robinson - Perception 1.7
     A reaction: A nice point, but it might not be entirely true in a blindfold test, where one might only report properties like 'sticky' or 'warm', without having any clear concept of the substance being experienced. Firth is proposing the 'percept theory'.
Sense-data are dubious abstractions, with none of the plausibility of tables [Quine]
     Full Idea: The notion of pure sense datum is a pretty tenuous abstraction, a good deal more conjectural than the notion of an external object, a table or a sheep.
     From: Willard Quine (On Mental Entities [1952], p.225)
     A reaction: This seems to sum up the view of sense-data held by the generation after Russell and Moore. Ayer still talks about them, but Russell had already given them up. The simple challenge is - what is the evidence for their existence? Cf innate ideas.
Do sense-data have structure, location, weight, and constituting matter? [Chisholm]
     Full Idea: Does a red sense-datum or appearance have a back side as well as a front? Where is it located? Does it have any weight? What is it made of?
     From: Roderick Chisholm (Person and Object [1976], 1.8)
     A reaction: A reductive physicalist like myself is not so troubled by questions like this, which smack of Descartes's non-spatial argument for dualism.
Sense-data are a false objectification of what is essentially subjective [Nagel]
     Full Idea: The private object or sense datum view is an instance of the false objectification of what is essentially subjective.
     From: Thomas Nagel (Subjective and Objective [1979], p.207)
We experience qualities as of objects, not on their own [Harré/Madden]
     Full Idea: It seems clear that we are never presented with a quality except of some object.
     From: Harré,R./Madden,E.H. (Causal Powers [1975], 3.II)
     A reaction: I'm not convinced that that 'seems clear'. The idea of sense-data is that while it seems to be of an object, reason suggests that the experience of the quality must precede the object assembled thereby. How do you arbitrate?
The Homunculus Fallacy explains a subject perceiving objects by repeating the problem internally [Evans]
     Full Idea: The 'homunculus fallacy' attempts to explain what is involved in a subject's being related to objects in the external world by appealing to the existence of an inner situation which recapitulates the essential features of the original situation.
     From: Gareth Evans (Molyneux's Question [1978], p.397)
     A reaction: This is obviously right, but we aren't forced to settle for direct realism. Inner perception may be very different, or we may employ the idea of Dennett and Lycan, that the homunculi don't regress, they deteriorate steadily down into mechanisms.
Sense data can't give us knowledge if they are non-propositional [Williams,M]
     Full Idea: Acquaintance with sense data is supposed to be a form of non-propositional knowledge, but how can something be non-propositional and yet knowledge?
     From: Michael Williams (Problems of Knowledge [2001], Ch. 8)
Sense-data are rejected because they are a veil between us and reality, leading to scepticism [Robinson,H]
     Full Idea: Resistance to the sense-datum theory is inspired mainly by the fear that such data constitute a veil of perception which stands between the observer and the external world, threatening scepticism, or even solipsism.
     From: Howard Robinson (Perception [1994], VII.1)
     A reaction: It is very intellectually dishonest to reject any theory because it leads to scepticism or relativism. This is a common failing among quite good professional philosophers. See Idea 241.
If we smell something we are aware of the smell separately, but we don't perceive a 'look' when we see [Crane]
     Full Idea: Visual perception seems to differ from some of the other senses; when we become aware of burning toast, we become aware of the smell, ...but we don't see a garden by seeing a 'look' of the garden.
     From: Tim Crane (Elements of Mind [2001], 5.40)
     A reaction: Interesting. Do blind people transfer this more direct perception to a different sense (e.g. the one they rely on most)?
The problems of perception disappear if it is a relation to an intentional state, not to an object or sense datum [Crane]
     Full Idea: The solution to the problem of perception is to deny that it is related to real objects (things or sense-data); rather, perception is an intentional state (with a subject, mode and content), a relation to the intentional content.
     From: Tim Crane (Elements of Mind [2001], 5.42)
     A reaction: Not clear. This definition makes it sound like a propositional attitude.
The 'disjunctive' theory of perception says true perceptions and hallucinations need have nothing in common [Lowe]
     Full Idea: The 'disjunctive' theory of perception says that we have either veridical perception or else hallucination, but there is no common element in the form of a 'perceptual experience' which would be present in either case and merely caused in different ways.
     From: E.J. Lowe (Introduction to the Philosophy of Mind [2000], Ch. 6)
     A reaction: McDowell is associated with this view. It seems to be another attempt to get rid of sense-data. It seems odd, though, to say that a hallucination of a dagger has nothing in common at all with experience of real daggers. Why did hallucinations evolve?
Sense-data are only safe from scepticism if they are primitive and unconceptualised [O'Grady]
     Full Idea: The reason sense-data were immune from doubt was because they were so primitive; they were unstructured and below the level of conceptualisation. Once they were given structure and conceptualised, they were no longer safe from sceptical challenge.
     From: Paul O'Grady (Relativism [2002], Ch.4)
     A reaction: The question of whether sense-data are conceptualised doesn't have to be all-or-nothing. As concepts creep in, so does scepticism, but so what? Sensible philosophers live with scepticism, like a mad aunt in the attic.