Which of your philosophical views are you least confident of? What do you think are the most compelling objections -- the ones you really take seriously, and are closest to being convinced by?
I'm perhaps most ambivalent about normative realism. The metaphysical extravagance and epistemological leaps of faith are certainly worth worrying about (though not, of course, decisive objections). My main reasons for accepting normative realism are (i) strong "Moorean" priors in favour, and (ii) the "might as well" argument that it can't very well be a normative fault to believe in normative facts. The belief is properly evaluable only if true, after all. [Update: Helen suggests a third option, of distinctively moral reasons, which I'll explore in a future post.]
Within ethics, I have trouble taking any thorough-going anti-consequentialist view remotely seriously. But that still leaves a lot of scope within the "broadly consequentialist" tent for uncertainty -- e.g. about the correct theory of value, whether there are agent-relative values, etc. So my self-identification as a "utilitarian" is rather more tentative, in at least three respects:
(1) Partiality: I've never had much sympathy for the idea that we must give extra weight to our own interests, but there's something much more compelling about the idea that it would be a deep mistake not to fundamentally value my wife more than (even comparably awesome) others. So I'm somewhat more agnostic about impartialism these days, and much less sure of the "might as well" argument that partiality could be at most permitted, not required.
(2) I'm also not entirely sure what to think about the non-identity problem, and whether we should be biased towards actually existent people -- preferring the actual state of affairs over another with a slightly better-off population consisting of completely different people. I certainly feel some pull towards the Cohen-conservative idea that our concerns should, in a sense, "latch" onto the actual things that are of value.
(3) Then of course there's the question of "welfarism" -- whether welfare is the only thing of value -- about which I have long been torn. I'm strongly inclined to think that various kinds of intellectual and cultural/artistic accomplishment have non-instrumental value. But they may be included as constituents of our welfare, so they don't make for clear counterexamples. Tricky questions also arise in the case of natural beauty -- is the waterfall in itself, or rather our appreciation of it, that has final value?
Moving on to metaphysics... The non-existence of popular deities seems pretty obvious to me, though once unbundled from the usual religious baggage I'd give some non-trivial credence to a non-traditional "creator deity", supported mainly by the fine-tuning argument.
Epiphenomenalism may be one of my most controversial views, though if anything it seems better supported than non-naturalist normative realism. (The arguments against naturalism's capacity to accommodate the phenomena are similar in both cases, but the phenomenon of consciousness itself is much more difficult to deny.) The most pressing worry is of course the paradox of phenomenal judgment, but the availability of correlative explanations -- together with the Humean observation that we never actually observe our qualia causing anything, but merely a "constant conjunction" between them and their apparent effects -- does pretty significantly mitigate the concerns, to my mind. As far as competing views go, I've nothing against Russellian monism / "panprotopsychism" -- in fact the view seems so similar that I hesitate to call it a "competitor" at all.
What about yourself, dear reader? What would you identify as your "weakest link(s)"? (Or, alternatively, how would your diagnoses of mine differ from the above?)