Lecture
16: Some
Questions about Colour
Ø What are the language-games described at
PI §§ 1, 2, 8 supposed to illustrate?
Ø `This was our paradox: no course of action
could be determined by a rule, because every course of action can be made out
to accord with the rule. The answer
was: if everything can be made out to accord with the rule, then it can also be
made out to conflict with it. And so
there would be neither accord nor conflict here.' He continues `It can be seen that there is a misunderstanding
here .....' (PI §201). Explain both the
paradox and the misunderstanding.
Ø Is meaning use?
Ø Give a critical account of EITHER
Wittgenstein's views of mathematical proof OR his attitude towards
contradiction in mathematics.
Ø At PI §98, Wittgenstein says `it is clear
that every sentence in our language "is in order as it is"'. At PI §109, he says `Philosophy is a battle
against the bewitchment of our intelligence by means of language'. Are these claims consistent? How does Wittgenstein regard the
relationship between philosophy and the investigation of language?
Ø Wittgenstein rejected the view that
thinking is an activity of the brain which is amenable to scientific
study. Are his criticisms cogent?
Ø
Discuss
Wittgenstein's claim that if there were a verb meaning `to believe falsely' it
would not have any significant first person present indicative, i.e. there
would be no use for `I believe falsely that p' (PI, p.190).
Ø
Can there be
transparent white?
If you choose to write on any of these
topics, ask me about associated literature.
2. In
the last one and a half years of his life, Wittgenstein spent most of his time
writing on the topics of certainty and colour. His remarks on colour were inspired by a
reading of Goethe’s Theory of Colour, but Wittgenstein does not think
that Goethe succeeded in producing a theory (RC I-70), nor does he attempt to
develop a theory of his own. He raises
a series of questions. Most of the
commentaries suggest that the manuscript now published as Remarks on Colour is
unsystematic – a series of scattered remarks.
But a recent commentator, Alan Lee, `Wittgenstein’s Remarks on Colour’
Philosophical Investigations 22/3 (1999), pp.215-239 has argued, to the
contrary, that Part I of the text (which is the latest version, it being 88
amended selections from the 350 remarks that occur in Part II) is quite
systematic and well organized. This is
an interesting paper, and I also recommend Elaine Horner, `”There cannot be a
transparent white”: A defence of Wittgenstein’s account of the puzzle
propositions’, Philosophical Investigations 23 (2000), pp.218-241.
3. According
to Lee, `[t]he central idea that gives structure to the text is the discovery
that it is an `internal’ or `timeless’
fact about white that, in contrast to the other colours, it is
opaque.’ You can have sunglasses in
almost every colour – but not white.
Why is transparent white impossible?
Wittgenstein seems to regard this as a conceptual question. At the beginning of RC, he distinguishes a
question like `Is this book darker in colour than that one?’ from a question
like `Is this shade of colour darker than that one?’. In the latter case, we are talking about internal
relations, and a true answer will be timeless. He wants a logic of colour concepts, not a psychological or
physiological theory of colour.
4. The
second proposition I-2 is a `phenomenological’ observation of which there are
many in the book. Curiously,
Wittgenstein says that there are phenomenological questions, but no
phenomenology. Further interesting
phenomenological points are made at I-7.
These relate to the impossibility of a yellowish blue or of a reddish
green. If some people claimed to see
reddish green, then, says Wittgenstein `we would still not be forced to
recognize that they see colours which we do not see. There is, after all, no commonly
accepted criterion for what is a colour, unless it is one of our colours’ (RC
I-14).
5. There
is a great deal of philosophical discussion about the metaphysics of colour,
where the issue is whether colour is a physical property of objects, or is a
disposition, or is dependent on the viewing subject etc.. There is also a scientific literature on how
our colour vision works. Wittgenstein’s
investigation is different from these investigations.
6. Fred,
who featured in Frank Jackson’s `Epiphenomenal Qualia’ could see red in the way
that the rest of us cannot – he makes an extra colour discrimination among red
objects that nobody else can make. It
seems possible that there should be such a person. But is it possible for any person to see reddish-green? The answer commonly given is `No’ on the grounds that, although there are
greenish yellows and brownish reds, there can
be no such colour as reddish-green. The italicised claim would be regarded by
Wittgenstein as stating something about the `logic’ of colour, while others
regard it as a necessary but a posteriori
truth. The latter position might be
defended by pointing out that we discover
that the pattern of stimulation of retinal cone types associated with red is
incompatible with the pattern associated with green. However, some recent research seems to show that, under certain
conditions, we can see reddish green,
and we shall explore some philosophical consequences of this, drawing heavily
on ongoing work by Fiona Macpherson (University of St. Andrews), to whom I am
indebted.
7. Colours
have an interesting structure, and not all colours are equal. Some are stand-alone. When you look at blue, for example, whether
it be royal blue, Cambridge blue, or some other shade of blue; it is not the
case that it looks a bit pinkish or a bit greenish, it just looks blue. So blue is one of the `unique colours’ and
the others are red, green and yellow.
By contrast, orange looks a bit reddish and it bit yellowish, so it is
called a `binary colour’ and there are, of course, many binary colours. The probable physiological explanation is
that there are two opponent processors, a red-green detector and a yellow-blue
detector. For perception of a binary colour such as orange, both processors
need to be excited. The processors are
opponent in that detection of red opposes (inhibits) detection of green and
vice-versa; similarly for yellow-blue.
8. By
means of an eye-tracker, a patch of colour viewed by a subject can be
stabilized on the retina, and when this occurs, after a few seconds that colour
fades from view and is replaced -- `filled in' -- by a colour that depends on
the colour of the surrounding area..
Macpherson reports a filling-in experiment performed by Crane and
Piantanida: `They presented subjects with joining red and green stripes. They ensured
that the boundary between the two colours was stabilised on the subjects'
retinas while the outer portions of the areas of colour were not
stabilised. The thought behind the
experiment was that the area that was to be 'filled in' was surrounded not by
one colour, but by two opposing colours, therefore, providing conflicting
information to the brain, when it tried to 'fill in' the area corresponding to
the stabilised part of the image. Observers of the image reported different
things that they saw in the stabilised area, which fell into the following
three categories:
(1) The entire field was covered in a regular array of very small (just resolvable) red and green dots
(2) The field contained either islands of red on a green background or vice versa
(3) The field contained a novel hue that subjects reported never having seen before
The experiment was repeated with blue and yellow areas, with corresponding results.'
9. It is the third of these categories that is of particular interest. Subjects report seeing a novel hue that some people say is logically impossible to see, or is physically impossible to see! If Crane and Piantanida are right, then, in the `filling-in' situation, the normal retinal channels, governed by the opponent processors, are bypassed, and the `filling in' is an independent cortical activity not constrained by the particular mechanism of the opponent processors.
10. There are various theories of qualia, and one that has come to prominence in recent years is Representationalism. This is the view that it is not just our intentional states, but also our phenomenal mental states are representational. Representationalists typically hold that a colour is an objective physical property (or a disjunction of such properties) and the experiences that have the phenomenal character of seeming to see that colour represent any of those properties.
11. If there really are experiences of seeing reddish-green, then the Representationalist has a problem. For the objective physical properties that constitute (say) red are identified as the properties shared by all and only those objects classified by normal observers under standard conditions. But there are no reddish-green objects observed by normal subjects under standard conditions. Given our optical mechanism, no object could look reddish-green to us under normal conditions. So what entitles the Representationalist to assert that the reddish-green seen by subjects under experimnetal conditions is an objective property (or a disjunction of such) that is represented in experience? We shall consider various answers.