"The Accretion of Truth"
Doubt is the prerequisite of truth. I don't buy the Millite idea of inevitable progress. But I do believe that one by-product of a free society is the advance of science and a better understanding of human nature. So we do not view women as we did a century ago. This is not simply a random, relativist change: it's because we now know the truth about the equality of women, we experience it daily, and our blind prejudices and cruelties have far less power . . . Ditto with race. And, so some extent, with abortion. Our ability, for example, to see the development of a fetus, to understand its development with far greater precision and detail than ever before, has inevitably sharpened our awareness of its humanness . . . And the reason our view of homosexuality has changed is not because we are somehow losing our sense of what is true or false: it is because we have a better, more informed view of what is true and false. This is not relativism. It is the accretion of truth. - Andrew Sullivan, quoted at The American Scene (hat tip: Ramesh Ponnuru at The Corner