Does knowledge convert reasons to your reasons?

August 31, 2008

In their forthcoming—and I must say excellent—paper “Knowledge and Action”, John Hawthorne and Jason Stanley defend the following principle:

The Reason-Knowledge Principle (roughly)
Where one’s choice is p-dependent, it is appropriate to treat the proposition that p as a reason for acting iff you know that p.[1]

Importantly, Hawthorne and Stanley say that this principle is to be situated within a decision-theoretic framework according to which knowledge that p requires credence 1 in p. The reason is somewhat obvious: if it is possible to know that p without having credence 1 that p, then any plausible decision theory will predict that there are cases where it is not appropriate to treat the proposition that p as a reason for acting even though one knows that p.  In any case where the expected value/utility of A is greater than that of B, but the expected value/utility conditional on p of B is greater than that of A, it is inappropriate to treat p as a reason.  In such a case, treating p as a reason would presumably require preferring B to A, which contradicts standard decision theory. On the other hand, if one’s credence in p is 1, then it cannot be the case that the expected value/utility of A is greater than B and vice versa for the conditional-on-p expected values/utilities of A and B. Hence, Hawthorne and Stanley require that knowledge that p requires credence 1 that p, thereby blocking any such cases.

This raises an obvious objection, an objection which Hawthorne and Stanley explicitly consider:

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Intuitions: Role and Reliability

August 21, 2008

At Thoughts Arguments and Rants, Brian Weatherson gives a new argument for the reliability of intuitions. His main idea is that, given how many falsehoods are counterintuitive, there is a strong prima facie case for intuition being reliable. To deny this prima facie case, one must either deny that there is a fact of the matter about the reliability of intuitions or that there is a singular notion of intuition, but both of these options look bad. I found both Weatherson’s argument and the ensuing discussion in comments thought-provoking, so here are some of my thoughts.

My main point will be that it only makes sense to talk about whether intuitions are reliable with respect to what one thinks their role is in philosophical enquiry.

Think about a different case first. Suppose I claim that the Bush administration is reliable in interpreting military intelligence data. Well, there is that whole Iraq thing. But think about the good cases: they haven’t invaded Fiji on false intelligence, or Madagascar, or Sealand, or many other nations. The Bush administration’s interpretations are in fact correct in most cases. Boring, in the sense that these interpretations simply agrees with commonsense, but correct nonetheless. Therefore, I claim that the Bush administration is reliable in interpreting military intelligence data.

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Does Lewisian combinatorialism imply quidditism?

August 19, 2008

From Combinatorialism to Legal Contingency

In “On the Plurality of Worlds”, Lewis endorses the following principle:

Lewisian Combinatorialism: For any x1,x2,… (perhaps from different worlds) and any spatiotemporal arrangement R (except one that co-locates two or more of its relata), there is a possible world where there are perfectly-natural duplicates y1,y2… of x1,x2,… (respectively), such that Ry1,y2,…

Definition: x and y are “perfectly-natural duplicates” just in case they have exactly the same perfectly natural properties.

It is rather uncontroversial, or at least it should be, that Lewisian combinatorialism implies that the laws of nature are contingent. Consider a (hopefully uncontroversially) possible world w where there are two positively charged particles p1 and p2 that bear the following spatiotemporal relationship to one another: at t0 they are d0 apart, at t1 they are d1 apart, at t2 they are d2 apart, where d1 is greater than d0 and d2 is greater than d1. By Lewisian combinatorialism, there is a possible world w* where there are two particles p1* and p2* which are duplicates of p1 and p2 (respectively) and which bear the following spatiotemporal relationship to one another: at t0 they are d2 apart, at t1 they are d1 apart, and at t2 they are d0 apart. In short, w is a world where p1 and p2 move away from one another and w* is a world where there perfectly-natural duplicates, p1* and p2*, move toward each other.

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Newcomb and Dominance

August 17, 2008

Hey All,

We never really talk about the Newcomb problem around here (never really == less than 75% of the time), so I thought I’d throw (what I think is) a new substantive line in the ring.

I assume a standard formulation of the Newcomb problem with an infallible predictor, which can be found here.  In the PDF below, I put forth an intuitively appealing argument for two-boxing in the Newcomb problem which employs dominance reasoning. I then suggest a potential issue with this argument as formulated. Much of the thinking that went into this was inspired by, among others, David Wiens, Stephen Campbell, Shen-yi Liao, and Jason Konek.

I’d appreciate any feedback here, especially reformulations of the two-box argument that stick to the intention of the original but employ different notions of dominance.

Some thoughts: Against a Newcomb Dominance Argument

Help with an example

August 11, 2008

I’m reworking some sections of my sovereignty paper and am stuck trying to think of a case that adequately illustrates a point I’m trying to make. Read on if you’re interested in helping.

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Yes! A Real Newcomb Case!

August 11, 2008

It’s time to reopen this can of worms. Michigan researchers have potentially discovered a gene responsible for both smoking and cancer:

“The gene is not the only element responsible for regular smoking, but it does signal a risk factor for nicotine dependency and cancer.”

Ann Arbor News reports on it here.

A more in depth article is here along with a citation to the research.