Actually, foie gras in not pate, it's just the goose liver itself.
It means "fat liver," and, as other's have stated, results from a goose being over-fed, to the point that the liver becomes enlarged and very full of fat.
I must admit, I have tried it before, and it is unlike any "liver"-like food you might have tried before... it is literally like butter, in a more solid form, and it was incredibly delicious...
But, knowing where it comes from, I swore off of it soon after I first tasted it. It just isn't right! I feel the same about how meat is raised in general... I am a card-carrying carnivore, truly, but I feel very strongly about humanely grown, humanely slaughtered animals... we should treat all of God's animals with respect and gratitude!
And if everyone supported cage-free, free-range, antibiotic- and hormone-free animal husbandry, the price would come down considerably... I still consider it a worthwhile investment now, but it is a considerable outlay!
And I especially refuse to buy anything but cage-free eggs and chicken! What they do to those poor chickens in those multi-national company plants is really detestable!!!