Abraham Lincoln once remarked to a fellow-passenger on an old time mud-coach that all men were prompted by selfishness. His fellow passenger was antagonizing this position when they were passing over a bridge that spanned a slough. As they crossed this bridge they espied an old razor-backed sow on the bank making a terrible noise because her pigs had got into the slough and were in danger of drowning. As the old coach began to climb the hill, Mr. Lincoln called out, “Driver stop just a moment.” Then Mr. Lincoln jumped out, ran back and lifted the little pigs out of the mud and water and placed them on the bank. When he returned, his companion remarked: “Now Abe, where does selfishness come in on this little episode?” “Why, bless your soul Ed, that was the very essence of selfishness. I should have had no peace of mind all day had I gone on and left that suffering old sow worrying over those pigs. I did it to get peace of mind, don’t you see?”  Taken from Feinberg, Psychological Egoism