Several authors have argued that act–utilitarianism cannot provide an adequate critique of buying meat because a single meat purchase will not actually cause more farm animals to be raised or slaughtered. Thus, regardless of whether or not the production of meat is inhumane to animals, someone who buys meat is doing nothing wrong. This argument fails to show that meat purchases are morally permissible, however, because it assumes that act–utilitarians would use actual utility in their decision to buy or not (...) to buy meat. I show that act–utilitarians cannot use actual utility as a decision procedure and must instead use expected utility to prescribe or proscribe actions. I then demonstrate how expected utility can be applied to cases of contributory causation, where many people seem morally responsible for causing something to happen. Buying meat is one case of contributory causation where the probability of any single individual's affecting meat production is slight, but the expected disutility of affecting that production is substantial. Thus, in its expected utility form, act–utilitarianism defeats the ‘causal inefficacy’ defence of buying meat [1]. (shrink)