our own happiness is important as well. it turns out that we are the kind of creatures that function well when we are happy. to devote ourselves completely to others’ happiness would make us unhappy, and, if everyone did this, suffering would increase, and utility would be diminished
we hold things like telling the truth in high regard because, in general, they maximize utility. therefore, all things being equal, it is best to tell the truth. that preserves a society where truthfulness is expected, and that allows us to cooperate successfully.
there are times, however, when lying may well serve us best, and we should be aware of this. for it is truth which serves us, not we who serve the truth