Philosophy of Probability


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Some words in my paper:

T(hj|ei)--fuzzy truth function of a predicate hj.

T(hj)--logical probability or  average thue-value of a predicate hj.

Popper defined Testing severity and Verisimilitude (1963/2005, 526, 534). Since Logical Probability and Statistical Probability are not well distinguished by him, his definitions are not satisfactory. The author suggests defining log [1/T(hj)] as testing severity, and T(hj|ei)/T(hj) as verisimilitude. In terms of Likelihood method, P(ei| hi is true)/P(ei) =T(hj|ei)/T(hj) is also called standard likelihood. So, we may say Semantic information = log (Standard likelihood) = log (Verisimilitude)=Testing severity - Relative deviation
 If negative verisimilitude for lies or wrong predictions is expected, one may also define verisimilitude by log [T(hj|ei)/T(hj)]. 

The figure 8 in the paper shows how positive and negative degrees of believe affect thruthlikeness. 

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Notwithstanding the arguments of Matthen&Ariew, there is still a simple and banal sense in which "natural selection is a cause of evolution". I presume Matthen & Ariew would not dispute that complex adaptations arise as the cumulative effect of the selection of genes. So the selection of genes causes the evolution of complex adaptations. 

As far as I can see, this claim is compatible with seeing the "selection" here as a statistical trend (or "outcome") rather than a causal process (or "force"). Of course, if by "evolution", one merely means "change in gene frequencies", it would be questionable to call selection a cause of evolution for all the reasons Matthen & Ariew give. But if one means "evolution of complex adaptations", selection most certainly is a cause, however one conceives of selection.
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Received views are an important part of our symbolic order. Once it becomes apparent that they cannot possibly be true, it is sometimes a valuable philosophical task to preserve them, since no rational and educated person could actually believe them. As an example of a critically endangered received view, consider Jerry Coyne's excellent book, Why Evolution Is True:
[T]he process of evolution -- natural selection, the mechanism that drove the first naked, replicating molecule into the diversity of millions of fossil and living forms -- is a mechanism of staggering simplicity and beauty.
The received view is that natural selection is a mechanism or process that shapes all living things, and that the study of natural selection explains a lot about the history of life on Earth. Natural selection makes it possible to treat the billion years of organic evolution as a coherent narrative, making biology an endless reserve of wonder, understanding, and enjoyment.

Matthen and Ariew (2002, e ... (read more)
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Cross-posted from


The handout for this week is here, the original paper is here.

I found this a particularly interesting paper. I’m in firm agreement with the main gist of Williams’ view- that the notion of typicality is in principle better adapted to deal with chancy similarity than the notion of ‘non-remarkableness’. That said, we found plenty of potential pressure points.

- Firstly, I’m not sure that quantum mechanics really has as wide-reaching consequences as is assumed in the paper. Depending on your response to the measurement problem, it could be that outcomes such as plates flying off sideways are not genuine quantum possibilities after all, because the low-amplitude branches are in some way ‘lost in the noise’. Although I think this issue is worth further investigation, I don’t think it’s critical to the debate between Williams, Hawthorne, and Lewis. Their worries can be raised about considerably less unlikely events – in fact, we can restrict ... (read more)

Cross-posted from


You can find the handout for this week here. I thought this was a really good paper, and we didn’t find all that much to criticise in it. It was a bit frustrating not to hear more about Fitelson’s positive story, in particular about the bridge principle that he would endorse instead of the various versions of RTE that he criticises. He’s clearly saving the juicy stuff for his book.

In particular, I find it hard to see how he plans to steer a middle ground between the Carnap/Williamson-style ‘a priori priors’ version of objective bayesianism, and the subjective bayesian approach. My naive take on the matter is that you either think that there’s a unique correct set of priors or you don’t. Maybe these priors aren’t a priori knowable (contra the Carnap/Williamson approach), although it seems that a position like this would be committed to complete epistemic rationality being in principle unattainable.

I wasn’t sure how strongly Fitelson m ... (read more)

I have spent some time recently reading various discussions of the Dutch book theorem. Nowhere have I found a really good explanation that sets out clearly and formally the conditions on rational betting preference that must obtain for the argument to work. (That's not entirely true, I found a good discussion of betting preference in [Halpern, 2003, Reasoning about uncertainty], but "the proof is left as an exercise"...

Have I missed some classic paper or book chapter in my (admittedly superficial) survey of the area?
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