Remarks on Color

Why do people find it intuitive to describe this kind of very powerful simultaneous color-contrast effect as an "illusion"? After all, the look of a color against a white background depends just as much on its background as the look of the spirals in the example depend on their background.

Here are some more simultaneous color contrast "illusions" from the same source as the first one.

Metamers seem to present a problem for physicalist theories of color. Make some yourself.

Another blow to the reliability of the inference from "I can't imagine the possibility of p" to "p is impossible": it might be possible for something to be simultaneously green and red all over.

Take a color discrimination test.

I Take A Stance; There is a World

A provocative argument discussed during Zed Adams's recent presentation to the Mind Workshop, "Color Relativism".

Painted Leaves, Desperate Smiles and Radical Contextualism

Charles Travis's attack on compositional, truth conditional semantics is built around a bunch of lively thought experiments, including cats dipped in puce dye ("Meaning's Role in Truth"), a guy named Sid who grunts when punched in the solar plexus (Unshadowed Thought), and a question about whether wearing a tie made of freshly cooked linguine would count as part of business attire (Ibid.). But one of Travis's examples has received more attention in the literature than any other. It involves one of his recurring characters, Pia, and the leaves of a Japanese maple tree. I'll quote part of the frequently cited passage:

A story. Pia’s Japanese maple is full of russet leaves. Believing that green is the color of leaves, she paints them. Returning, she reports, “That’s better. The leaves are green now”. She speaks truth. A botanist friend then phones, seeking green leaves for a study of green-leaf chemistry. “The leaves (on my tree) are green”, Pia says. “You can have those”. But now Pia speaks falsehood. ("Pragmatics")

There's a lot to say about what happens in that short paragraph, and a lot has been said about it. One thing to say about the example is that Pia's motivation for painting the leaves is odd. Who would want to paint leaves to make the world conform with the belief that leaves are green? In an unpublished paper that takes up the question of the painted leaves (which he has since modified in very interesting ways), Jason Bridges says of Pia's action and utterance, "When I imagine someone doing and saying this, I can’t help but envision her with a fixed, desperate smile".

Jason may be right about the oddity of Pia's actions as described in Travis's example. But leaves get painted for all sorts of reasons, not all of them strange. Stuck to the side of houses, they get painted inadvertently (more here and here); they get painted intentionally as a way of indicating that they are to be removed; and simply because it looks interesting.

The philosopher of language Stefano Predelli, who has a provocative paper that responds on behalf of compositional, truth conditional semantics to the example of the painted leaves, managed to find and get his picture taken next to some actual, vividly painted leaves. (His other pictures are worth seeing as well.)

Searches on Flickr also yielded pictures illustrating another one of Travis's examples, which involves ink that looks black in the bottle but which writes blue (Unshadowed Thought). It turns out that it is hard to tell what color ink will write simply by seeing it in the bottle. Almost all ink in the bottle looks black if the bottle is completely full.

Illustrations of more classic thought experiments surfaced as well, including a barn facade, a mule painted to look like a zebra, and a possible robot cat.

Can You Have a Demonstrative Thought About a Color?

Last night the workshop met for the final time this academic year to discuss Rachel Goodman's paper "Demonstrative Thoughts as a Response to Lewis". Both the paper and discussion were complicated and interesting. I'll just summarize a few central topics here.

Rachel's target was anyone who wanted to respond to Jackson's knowledge argument by saying that what Mary acquires when she leaves her black and white room is the ability to have demonstrative thoughts about colors. Jason and David tentatively suggested that they were interested in that way of describing what happens to Mary when she leaves the room during the last meeting of the workshop.

Rachel's strategy was to try to show that there are disanalogies between a paradigmatic kind of demonstrative thought that concerns objects individuated according to their location in space and time and putatively demonstrative thoughts that concern colors. If the disanalogies are great enough then it would be a mistake to say that what happens to Mary when she leaves the room is that she acquires the ability to have demonstrative thoughts about colors.

First Disanalogy

The central disanalogy that Rachel wanted to argue for involved the possibility of a certain kind of failure that is present in the case of demonstrative thoughts about spatio-temporal objects that isn't present (she claimed) in the case of (putative) demonstrative thoughts about colors. That failure is the following:

It is possible to have the thought That cup is blue, while thinking about a BOTTLE, and still successfully have an object-dependent thought about the bottle. That is, you can apply the wrong sortal and still succeed in having a thought that is about an object (as long as it is in roughly the right place in space and time). Rachel wanted to say that in such a case you still succeed in having an object-dependent demonstrative thought.

In contrast, Rachel claimed, you can't have the same kind of failure in the case of a putatively demonstrative thought about a color. So, for example, it wouldn't be possible to think That color is beautiful, while getting the sortal wrong and still having an object-dependent demonstrative thought. It wouldn't make sense to say that you managed to have a thought about a TEXTURE or a SHAPE, for example, if you took yourself to be referring to a color. It was on the basis of this disanalogy that Rachel claimed it wasn't possible to have demonstrative thoughts about colors.

Members of the workshop objected to this line of reasoning in different ways.

Jason didn't think you could have an object-dependent demonstrative thought in the case where you apply the wrong sortal to the cup.

Justin suggested that there was a corresponding kind of failure in the case of a color, if the sortal was chosen correctly. So, for example, you might think That pastel is beautiful, and be mistaken about the fact that the color you demonstrated was a pastel (maybe it was flourescent or neutral).

Second Disanalogy

At another point in the discussion, Rachel said that unlike demonstrative thoughts about spatio-temporal objects, thoughts about colors didn't involve a "mapping" of egocentric features onto objective features. When you have a demonstrative thought about spatio-temporal objects, you think about That cup both as located in space relative to you and as located in objective space. But in the case of putative demonstrative thoughts about colors, Rachel claimed that there wasn't an analogous mapping of subjective features (in this case, something like color phenomenology) onto anything objective. I objected to this suggestion because insofar as someone can recognize a difference between how things seem to him (say I'm wearing 3-D glasses and everything appears either red or green) and how those things really are colored, then there is the possibility of a "mapping" of subjective features of experience onto (more or less) objective features.

There was also discussion of McDowell's notion that having a demonstrative thought about a color involved the presence of a sample. Jason and David discussed the possibility of a thought that depended not on the presence of the object that it is about, but on the presence of some other object (the sample). We didn't make much headway on this topic, however.

After the workshop, we watched a discussion between Gareth Evans and P.F. Strawson on the nature of truth, filmed for the Open University in 1973.

This was the last meeting of the mind workshop for this year. The workshop will resume in the fall, with a new grad student organizer: Will Small.