a.k.a. “Reason versus Rationalisation”
From Mémoires de la vie privée de Benjamin Franklin:
I believe I have omitted mentioning that in my first voyage from Boston, being becalmed off Block Island, our people set about catching cod and hauled up a great many. Hitherto I had stuck to my resolution of not eating animal food, and on this occasion, I considered with my master Tryon the taking of every fish as a kind of unprovoked murder, since none of them had or ever could do us any injury that might justify the slaughter. All this seemed very reasonable. But I had formerly been a great lover of fish, and when this came hot out of the frying pan, it smelt admirably well. I balanced some time between principle and inclination, till I recollected that when the fish were opened I saw smaller fish taken out of their stomachs. Then thought I, if you eat one another, I don’t see why we mayn’t eat you. So I dined upon cod very heartily and continued to eat with other people, returning only now and then occasionally to a vegetable diet. So convenient a thing it is to be a reasonable creature, since it enables one to find or make a reason for everything one has a mind to do.