The sentiment to which [the utilitarian] appeals is generalized benevolence, that is, the disposition to seek happiness, or...good consequences, for … - J. J. C. Smart

Another type of ultimate disagreement between utilitarians, whether hedonistic or ideal, can arise over whether we should try to maximize the average happiness of human beings...or whether we should try to maximize the total happiness or goodness...Would you be quite indifferent between (a) a universe containing only one million happy sentient beings, all equally happy, and (b) a universe containing two million happy beings, each neither more nor less happy than any in the first universe? Or would you, as a humane and sympathetic person, give a preference to the second universe? I myself cannot help feeling a preference for the second universe.

Nor is this utilitarian doctrine incompatible...with a recognition of the importance of warm and spontaneous expressions of emotion. Consider a case in which a man sees that his wife is tired, and simply from a spontaneous feeling of affection for her he offers to wash the dishes. Does utilitarianism imply that he should have stopped to calculate the various consequences of his different possible courses of action? Certainly not. This would make married life a misery and the utilitarian knows very well as a rule of thumb that on occasions of this sort it is best to act spontaneously and without calculation.

Normally the utilitarian is able to assume that the remote effects of his actions tend rapidly to zero...It seems plausible that the long-term probable benefits and costs of his alternative actions are likely to be negligible or cancel one another out.
An obviously important case in which, if he were a utilitarian, a person would have to consider effects into the far future, perhaps millions of years, would be that of a statesman who was contemplating engaging in nuclear warfare, if there were some probability, even a small one, that this war might end in the destruction of the entire human race. (Even a war less drastic than this might have important consequences into the fairly far future, say hundreds of years.) Similar long term catastrophic consequences must be envisaged in planning flight to other planets, if there is any probability, even quite a small one, that these planets possess viruses or bacteria, to which terrestrial organisms would have no immunity.