I've now watched this debate between William Lane Craig and Shelly Kagan twice: once alone and once with interested ethics students (for extra credit!). It's very good, and Kagan pushed buttons on Craig's arguments in many of the ways I thought that his arguments should be pushed.
There's an intuition that if there is no God or afterlife, then life loses its significance. Paul writes, "If the dead are not raised, 'Let us eat and drink, for tomorrow we die'" (1 Cor. 15:32b). The author of Ecclesiastes (2:15-16) writes
Then I thought in my heart, 'The fate of the fool will overtake me also. What then do I gain by being wise?' I said in my heart, 'This too is meaningless.' For the wise man, like the fool, will not be long remembered; in days to come both will be forgotten. Like the fool, the wise man too must die!
Craig has written,
Mankind is a doomed race in a dying universe. Because the human race will eventually cease to exist, it makes no ultimate difference whether it ever did exist. Mankind is thus no more significant than a swarm of mosquitoes or a barnyard of pigs, for their end is all the same. The same blind cosmic process that coughed them up in the first place will eventually swallow them all again. (Reasonable Faith, p. 59, 1994 edition).
Many existentialist philosophers have seemed to agree with this line of thinking. You get this impression from Sartre, Camus, and Nietzsche.
Kagan calls this into question. In his closing statement, in the last minutes of the recording, he says,
It seems to me that one essential point of disagreement between Craig and me is something that I asked about several times. It's this move that, to my mind, is the move from the thought that, without theism, then our actions don't have eternal cosmic significance, to the conclusion that, therefore, without theism our actions don't have significance - objective, moral significance. That just seems to me to be a mistake. It seems to me that if I love somebody, the reality of that loving relationship is valuable, of real value, of genuine objective value, and it's not in any way threatened by the fact that I will die, my wife will die, my children will die ,and eventually the universe will come to an end. The fact that billions and billions of years from now, it's all going to be the same doesn't mean it's all the same now. I certainly want to concede that if you're looking for this kind of cosmic significance, atheism's not going to provide it for you. But that wasn't the subject of tonight's debate. The subject of tonight's debate was whether you needed that kind of cosmic significance to have morality, and on that issue, I'm quite confident that the answer is 'no'.
I take Kagan to be insightfully calling into question this premise:
1) If x does not have eternal, cosmic moral significance, then x does not have objective, moral significance.
And I must say that (1) still has a strong pull on me. Yet, Kagan's reasoning in his quote here (and throughout the debate) seem compelling as well. I was wondering if anybody had arguments either for or against (1).