While there are some nice, interesting bits on vagueness, I honestly think this book is overrated and sort of a waste of time.

The first half of the book is spent arguing against those who think philosophy is and ought to be mere analysis of language or concepts. Much of what Williamson says here is true (philosophy's subject matter is the world, not language) but it's wasted time for anyone that agrees with him, and there's a sense in which he gives too much credit to the latter day conceptual analysts. Perhaps it's because the Brits are still suffering from some mild strains of the Wittgensteinian cancer and the subsequent ordinary language virus.

The second part of the book is, roughly, a defense of the current Anglo American philosophical zeitgeist (or the status quo) via an explanation, explication, and defense of modality and the efficacy of thought experiments in terms of counterfactuals. That is, since we all readily employ counterfactuals in our everyday reasoning and since we can understand modality et al in terms of counterfactuals there's nothing weird, spooky, or off putting about necessity-talk (Quine be damned).

This whole view is built up on an un-argued for reliablist justification of our knowledge of counterfactuals. Since reliabalism is indefensible, there seems to me to be a rather big hole in Williamson's project.

All in all, I agree with many of Williamson's conclusions; nonetheless, I think many of them are based on bad epistemology. There *really is* a problem about our knowledge of necessity and possibility. I don't really think anyone has solved it, even though I am sure we have such knowledge. It seems like Williamson is less interested in solving problems and more interested in providing a sort general justification of (or apology for) a certain sort of methodological attitude that's prevalent in contemporary "analytic" philosophy. ( )