"It is perfectly true, as philosophers say, that life must be understood backwards. But they forget the other proposition, that it must be lived forwards. And if one thinks over that proposition it becomes more and more evident that life can never really understood in time simply because at no particular moment can I find the necessary resting place from which to understand it—backwards." ~ Søren Kierkegaard
This is commonly (but INCORRECTLY) quoted as "We live forward but understand backwards."
-- “We hate some persons because we do not know them; and we will not know them because we hate them.” ~Charles Caleb Colton
