Why you should be an Illusionist (an elevator pitch):

Something like this will turn into a post soon. I just had a very pleasant and illuminating conversation about it and want to get the thoughts on paper, also I’ve had some lovely conversations with Ishmael Hodges and Benjamin J Curtis where I largely play defense, so I consider this a long over due positive proposal.

Step one: Recognize that Santa isn’t in your mind.

We often say false things, and it is important to recognize that they are false. Sometimes we say things that are false, but we don’t mean what we say, and what we mean is true. When I say “Santa Claus lives at the North Pole,” we all agree this is true. But, strictly speaking, what I said is false. Santa Claus does not live at the North Pole because if you listed out everyone who lives at the North Pole, Santa Claus would not appear on the list. Similarly, when we engage in the mental activity of picturing we are apt to say that the thing pictured is ‘in our mind.’ But when I am picturing Santa Claus in a sleigh, I may be apt to say “Santa is riding his sleigh in my mind” or something like that, but strictly speaking, this is false. If I made a list of all the people riding sleighs, Santa Claus would not appear on the list.

Step two: Recognize that Sense Data Theory makes the same mistake.

We often think false things. When I look at the Muller Lyer I may think that there are lines of two different lengths in front of me, when there are not. Some philosophers have argued in the following way: I see two lines of different lengths, but there are not lines of two different lengths out there, so there must be somewhere that has two lines of two different lengths, so there must be a mental entity (which I shall call Sense Data!) which has two different sticks in it of different lengths. The sense data has all the properties that I mistakenly attribute to what I see. If I think I see something brown, which is actually red, my sense data is brown. But this argument makes just the same mistake as our thought about Santa Claus. To see that it does, imagine that I have an odd sensory disposition to see colors never instantiated. This is easiest to imagine with purple, since it is (often) difficult to find naturally. Suppose I see a log colored a shade of purple which nothing has ever been colored (call this purple*), it would be a mistake to think, then that there is something which is purple* colored, for exactly the same reason it would be a mistake to think there is someone who lives at the north pole.

Step three: Didn’t you just deny qualia?

If qualia aren’t sense data, what are they? What is the qualia property equivalent of being purple* colored? “Having the phenomenal property purple*-ness” is just more jargon. Something-something ‘what-it-is-likeness’ is more jargon. I submit that the intuition behind the existence of qualia is just the same intuition that supports the sense data theory. This claim has multiple lines of evidence in support: the term qualia originally developed from sense data theory with C. I. Lewis, sense data are supposed to have exactly the same epistemological properties that qualia have (e.g. you can be certain of your sense data, but not of what they depict, and you can be certain of you qualia, but not what they depict), and sense data (much like qualia) appear difficult to reduce to the physical. Indeed, the way sense data are reached seems to itself imply an anti-physicalist argument! We infer the existence of some mental stuff, sense data, because nothing in the physical world can have the properties the sense data must have ex hypothesi. The sense data is supposed to have two sticks of different length, but there are not two sticks of different length out there in the world, there certainly are not two sticks of different length in my brain, so where are we to place the sense data, physically?

Step four: from the top.

No one lives at the North Pole, so what you say when you say “Santa Claus lives at the North Pole” isn’t strictly true. What you mean to say is true (something like “In the fictional world of Christmas stories, Santa Claus lives at the North Pole.”) What you say when you say “Santa Claus is riding a sleigh in my mind” is also not true, because if you listed everyone riding sleighs at the moment, Santa Claus would not appear on the list (if you don’t find this example persuasive, swap out ‘sleigh’ in both sentences with ‘Ford F150’ and try again). Finally, what you say when you say “I am having a red experience” isn’t, quite, true. Your experience isn’t red. It does not have the property of ‘redness.’ Nor does your experience have the property of ‘what it is like to see red,’ because these come to the same thing (see above). So there are no phenomenal properties.*

PEDANTIC NERD ADDENDA:

In this last part about ‘having a red experience’ I’m running roughshod over some tricky issues of semantics that I’d rather spell out more. Maybe ‘red experience’ doesn’t actually mean ‘red brain state’ or something like that, in fact it almost certainly doesn’t. But for the sake of symmetry and illustration and brevity, I’m going with it here. The important point to take away is that the motivation for believing there are qualia is basically the same as the motivation for believing there are sense data, because they are the same thing. The motivation for believing in sense data sucks, for Santa Claus reasons, so you should think the same about the motivation for thinking there are qualia, because the motivations are the same. All of this is independent of getting into the impenetrable void of folk semantics, so if you agree with all of this substance, I’m happy to let the semantic point go.