People sometimes ask me why I'm a consequentialist. This is a difficult question to answer productively, since direct introspection merely reveals my deep-rooted sense that non-consequentialist views just don't make sense. There's probably no single argument that's responsible for this intuitive response. But it might at least be fun to brainstorm a few considerations that could plausibly lead one to favour consequentialism...
(1) The 'fundamentality of value' intuition: It seems very plausible that morality (insofar as it's worth caring about) is fundamentally concerned with making the world a better place. This seems a more attractive conception of action-guiding normativity than the old-fashioned conception of morality as a list of "do"s and "do not"s.
Put another way: Suppose you have a choice between two actions, one of which makes things better, and the other makes things (comparatively) worse. Doesn't that seem to settle the question of which action is most worth choosing? We may wonder: How could it be wrong to choose the action that (predictably) makes things turn out best?
(2) Skepticism about doing/allowing and related distinctions. Whether it's doing vs allowing, or intended vs merely foreseen, the kinds of distinctions that deontologists rely upon just don't seem significant enough to be able to pull such normative weight. As such, non-consequentialist views end up looking like mere flimsy rationalizations for status quo bias.
(3) The Paradox of Deontology: It seems somehow incoherent to hold that one shouldn't perform certain kinds of actions even to prevent the occurrence of more such bad actions. (As G.A. Cohen put it, "if such sacrifice and violation are so horrendous, why should we not be concerned to minimize their occurrence?") See also Parfit's argument that common-sense morality is collectively self-defeating.
(4) "God's eye view" arguments: It seems that an ideal (benevolent, omniscient) observer would want us to perform the actions that make things turn out best. And it's plausible that the prescriptions of such an ideal observer would coincide with those of morality (why would they differ?). Similar remarks apply to the Veil of Ignorance.
(5) Equal Concern: In light of points 2 and 4 above, consequentialist impartiality seems like the most principled way to treat everyone equally (thereby satisfying an appealing and plausible candidate, rivaling point #1, for 'what morality is fundamentally about'). Again, the rivals seem to rest on either some kind of status quo bias, or else confused notions about what constitutes treating people with equal concern.
Have I missed anything? What do you consider the strongest reasons in favour of consequentialism?