I’m off for a few days while I head over to Amsterdam for Christmas. I will be back early in the New Year with hopefully some slightly more polished things to say about modus ponens failures, Dr. Evil and countable additivity, privileged access and narrow content, and, it being unavoidable in January and February, philosophical gossip. (Though I can’t promise that the gossip will be polished – I half think I should promise that it will not be.) Happy holidays all, and good luck to everyone going on the job market!

Posted by Brian Weatherson at 9:23 pm

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I was updating a few links when I discovered
something I didn’t really expect to find out during a regular webcrawl. If you crawl
on over to John
Hawthorne’s CV, and scroll not too far down, you’ll see that he has a paper
forthcoming in The Monist, co-authored
with me. This is very
exciting news, especially to me!

Despite the somewhat incredulous tone of the last
paragraph, I was more or less aware that the
paper was more or less likely to appear,
so it wasn’t like I had a paper accepted at a journal with no knowledge of it
(and in fact I even have a draft
of the paper available) but it still wasn’t exactly how I expected to get
confirmation of another publication. I wonder if news of its acceptance is official
enough to put on this year’s annual report?

In other co-authoring news, it looks likely that
the paper Andy Egan and I wrote on pranks
will be presented at the Symposium
on Theoretical and Applied Ethics at LSU next February. I think it’s my
duty to play this up for all it’s worth – it’s only fair that adding a few
jokes to a good idea for a paper that someone else (i.e. Andy) had gets me to
count as an ethicist. I’m not sure why it’s fair, but
now that I’m an Ethicist, I can just say that it’s fair and that’s already got
some evidential weight.

Posted by Brian Weatherson at 6:43 am

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Well, here’s something you don’t see every day. The review in Notre Dame Philosophical Reviews of Beyond Rigidity takes Soames to task for not being Millian enough. That’s the kind of thing that happens in any field when you stake out an extreme position early on, any subsequent movement back towards the middle ground will be interpreted as betrayal by someone

Posted by Brian Weatherson at 1:55 am

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Posted by Brian Weatherson at 4:18 pm

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I’ve had a few complaints about the way pictures work on the blog, so I’ve deleted the posts involving graphics. So from now on it’ll just have to be me talking. That might not be a good thing, but we’ll see.

Posted by Brian Weatherson at 1:12 pm

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In
both my recent notes on indifference principles, the comments on Nick Bostrom’s
computer simulation paper and Adam Elga’s Dr Evil paper, I’ve mentioned that
the proponents of these theories assume a theory of evidence that is
intuitively quite plausible, and may have been the mainstream view not long
ago, and may even be ultimately true, but which is not very popular among
philosophers of perception these days. I didn’t think much followed from this,
save perhaps that those presupposing a theory that is widely viewed as being
hopelessly befuddled owe us an explanation as to why they are sticking with it.
And in this little endeavour I have been utterly unsuccessful. This could be
because my heart hasn’t really been in it due to underlying internalist sympathies,
or because I’m wrong that the indifferentists need to address this, or because
I’m no good at convincing people of things, or because of any number of other
reasons. Suffice to say that in some circles, the idea that when we look at a
hand we have evidence of an epistemically different kind to a brain-in-a-vat
that is stimulated in the way our brains are when we look at a hand is not
viewed as being particular plausible.

When
in trouble in a case like this, call in the heavy hitters. Alex Byrne has a paper
forthcoming in Noûs in which he
argues that the sceptical
paradoxes are not really deep paradoxes. By this he means, in part, that
there isn’t anything like a compelling argument for scepticism. And this is because
he thinks that the canonical arguments for scepticism turn out to rest on very
implausible premises on close inspection. One of those premises is that
perceptual evidence underdetermines what the external world is like: we could
have just this evidence and be dreaming (or a brain-in-a-vat, etc.). This,
Byrne thinks, can be shown to be false simply by carefully reflecting on the nature
of evidence. The whole paper is worth reading, but let me just extract a few
choice quotes.

          The
known (evidence) proposition e has yet to be identified. [Byrne has just
argued that evidence should be propositional. The challenge is to determine
whether there is any candidate to be e that is compatible with
thorough-going external world scepticism.]The candidates may be divided into
two classes. The first—class I— consists of propositions about S’s sense-data,
ideas, impressions, phantasms or other queer entities allegedly “given” in
experience. The second—class II—consists of propositions about how things look
or (visually) appear to S (cf. the first paragraph of this section [not
excerpted here.]).

          It
is quite doubtful that (trivial exceptions aside) any propositions in class I
are true, a fortiori known; they may accordingly be dismissed. This
would have sounded dogmatic as recently as the first half of the twentieth
century: it is only in the last fifty years or so that the deep flaws in what
used to be called the “representative theory of perception” have become
gradually visible. Admittedly, not everyone agrees that the theory rests on a
soggy bog of error: in one form or another, it still has its defenders. However,
it is unnecessary here to rehash the argument: because we are playing the first
sceptical game, the sceptic must steer clear of philosophical controversy.

          That
leaves the members of class II: propositions about how things look or appear to
S—in other words, certain propositions about S’s mental states.
But because the representative theory of perception is off-limits, there is
very little motivation for thinking that one’s knowledge of the external world
rests on a foundation of knowledge about one’s own psychology…

          Propositions
about how things look or appear to S can be divided into two types. The
first—type II_E—comprises external world propositions,
because they entail the existence of o: that o looks square to S,
that it appears to S that o is square, etc. Hence, propositions
of type II_E, despite not entailing p, and perhaps being
known by S, are quite unsuitable candidates to be e. For e is
not supposed to be an external world proposition.

          The
second—type II_I—comprises those propositions about how
things look or appear to S that are not external world propositions (or
so we may suppose): that it appears to S that (some x) x is
square, that it appears to S that the F is square (for various fillings
for ‘F’, e.g. ‘tile’, ‘pink thing’), etc. If e is to be found in
class II, it must be of type II_I.

          [I]t
is not plausible that e is a type II_I proposition.
First, these propositions have to be true; clearly we need not suppose
that it appears to S that the tile, or the pink thing, is
square. But is it even clear that it must appears to S that (some x)
x is square? If not, then since there are no better candidates, e is
not a type III proposition. Second, S believes e, and it is
quite unobvious why S, if he is to know p via his senses, must
have any beliefs about how things appear, let alone believe one of the
specific propositions under consideration. Suppose S is a conceptually
challenged animal who cannot entertain these comparatively sophisticated
thoughts about appearances; does this fact alone imply that S cannot use
his eyes to come to know that o is square?

Posted by Brian Weatherson at 11:40 pm

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Kieran
Healy writes on the (slow-)growing controversy over the role of intuitions
in philosophy. For background, see the papers by Jonathan Weinburg et
al here,
here
and here. (If you haven’t seen the survey results about intuitions on Gettier cases across cultural and social groups in these papers yet, you should. And prepare to be a little suprised.)
Kieran has a rather funny caricature of the way philosophers (or at least
metaphysicians) generally argue, but then goes off on a riff about why we
should care more about where intuitions come from.

In the meantime, you might be interested in looking at other writers, who
have explored the
idea that our intuitions might have institutional
roots; that culture might mold conceptions
of rationality and thus deeply affect
how you think; that classification
is a social process which might have its origins in
material life; and that although individual and social cognition interact in
complex ways, getting socialized into a culture often implies subscribing
to its point of view.

I’m
not sure how any of this undercuts the use philosophers make of intuitions. It
seems to me that even if we acknowledge all of this, there are still epistemological
and metaphysical reasons to use intuitions in philosophy. (You
mean you’ll be defending philosophy by using more philosophy? Yeah,
well what did you expect me to use, chemistry or something?)

The
epistemological reason is that for each of these facts about intuition, we
could (I think) find an equally
disturbing fact about perception. How we see the world around us is affected by
the kind of culture we’re in, what we expect to find and so forth. But none of
that implies that we should stop trusting perceptions as a source of evidence,
provided we’re suitably careful about how we employ them. Of course, practically
nothing should stop us trusting perception as a source of
evidence; that way lies madness, if not philosophical
immortality.

The
metaphysical reason is that intuitions are sometimes constitutive of the
concepts we’re aiming to analyse. Want to know what’s a house? Well, presumably
houses are things that satisfy the predicate “house”, or fall under the concept
HOUSE. And presumably the facts about what makes an object satisfy the
predicate “house” include facts about how the term “house” gets the meaning it
gets in the language we speak. And presumably those facts include facts about
the intuitions people have about houses. A similar story is probably true for
the concept HOUSE, though here there are some more prominent
dissenters. Now it’s rather controversial whether a similar story could be
true if we replaced “house” with “item of knowledge”, or “rational belief”, or “mind”,
or “person”, or “just act”, or (I guess most controversially) “object”, but at
least for terms towards the left of that list, it seems plausible enough.

Posted by Brian Weatherson at 9:18 am

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Brad
DeLong writes that he only just realised that there could be non-spectral
colours.

Until yesterday, it had never occurred to me that I could see colors that
weren’t in the spectrum—I had thought that all colors were somewhere in the
rainbow (or could be made from rainbow colors by darkening or lightening them).

But that is clearly false. Consider magenta. A magenta light plus a
green light equals a white light—all colors. But green is in the middle of the
spectrum. So where in the spectrum is magenta? Magenta is red and blue—the
complement of green. And nowhere in the spectrum is there a wavelength of light
that excites both the red-cones and the blue-cones but does not excite the
green-cones.

I was
going to write a comment saying just how magenta was possible, then I realised
I wasn’t exactly sure. Then I was going to link to a website that explained it
all clearly, until I realised I couldn’t find one. So if anyone could enlighten
me, or Brad, please write in!

Here’s
what I think happens, though I’m not entirely sure. The spectral colours are
colours produced by light of constant length. But we know there’s lots of waves
that do not have constant wave lengths. This is obvious for sound: you never
hear the sound of a trumpet, even a trumpet playing a ‘constant’ note, when you
just listen to waves of constant length. Magenta, I think, is one of the things
that happens when the light in question is not a wave of constant frequency.

But, that
doesn’t really say enough about what happens. I don’t know how the waves ‘mix’.
Is it that magenta light contains only photons of a constant frequency, but
some of them are around the typical frequency of red light and some of them
around the typical frequency of blue light? Or is it that individual photons
‘vibrate’ in some non-sinusoidal pattern, as the air does when two or more
notes are played? Or does this distinction not really make sense when we’re
dealing with light?

And
I’m not even sure this is the right story about magenta. I think it is, but for
all I’m certain of, magenta could be a contrast colour, like brown, that is
only apparent when there are other visible colours with which it contrasts.

Some
might think that it’s embarrassing how little I know about colours, but (a) if
I was going to be embarrassed by my ignorance there are many other things I’d
be embarrassed about first, and (b) since my department already has an expert on
colour, the marginal value of my learning more is not very high.

Posted by Brian Weatherson at 7:33 am

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Posted by Brian Weatherson at 1:45 am

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Sometimes I think it would be fun to run a critical
thinking course focussing on how to spot fallacious reasoning that only ever used examples drawn from the contemporary media.
Depending on how sensitive Brown students are, I could end up getting accused
of every sort of bias imaginable. (And the evidence is that some of them are much
too sensitive.) But I don’t have such a course yet, so I’ll have to stick
to the blog. This is from the Washington
Post.

"This Lott
story has continued primarily because of criticism from conservatives,"
said Whit Ayres, a Republican pollster based in Atlanta. “If the only people
raising doubts were Jesse Jackson and Al Sharpton, this story would have died
of its own weight several days ago. It’s the anguish from conservatives that
has kept the story going.”

Um, yeah. The hidden premise here that only
people who ‘raised doubts’ were Jesse Jackson, Al Sharpton and conservatives.
Given that extra premise, the conclusion that “it’s the anguish from
conservatives that has kept the story going” I guess would follow. And you
know, if you’re prepared to count Josh
Marshall, Paul
Krugman and Al
Gore as conservatives, well the hidden premise still wouldn’t be true, but
at least there wouldn’t be a refutation I could find within five seconds of
scanning the NY Times.

Posted by Brian Weatherson at 12:13 am

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