Classical utilitarianism demands that one act in such a way as to produce the best consequences on the whole. Unfortunately, “on the whole” means for all human beings who live now and will live in the future until the end of time. Call this the “till kingdom come” requirement or TKC. Obviously, utilitarianism thusly understood is an impossible ideal. I will now prove that this is precisely what makes it so useful.
Logically, there are 4 possibilities for any human action: one does
- good; and good will come out in TKC;
- good; and evil will come out;
- evil; and good will come out;
- evil; and evil will come out.
Clearly, (4) is utterly wrong.
But so is (3) from the actor’s point of view: as I pointed out, if one does evil, yet good comes out of it in TKC, then it is shame to him, and glory to God. But, one shall reason, “God already has enough glory, and I, very little; surely, it will not diminish God’s greatness if I take a little of it for myself even at His expense.”
It follows that it is only rational to do good. But one is powerless to ensure or even know in this life that (1) will come to pass as opposed to (2). But the only way to inner peace is to hold that there is such thing as divine providence that will make sure that doing what seems good immediately will also produce good in TKC. Otherwise, man is not only a tragic figure who acts blindly without knowledge or prudence but a contemptible, disgusting one. For example, how can the doing of good be rewarded if it yields evil on the whole in TKC? Such a thing may be forgiven, but it cannot be praised or glorified.
If God loves His children, then He has to, lest those children suffer ignominy and be branded worthless fools, harmonize plausible basic calculations of common morality and remote consequences of following it all the way up to TKC.
Atheism or even deism which deny divine providence then sabotage the moral enterprise, as deists cannot be sure that their doing good is of any value in the TKC.
Deists then may be “good people” who do not kick dogs, but they can never be sure that abstaining from kicking a particular dog is not a terrible mistake.