A video lecture in 3 parts, and a peer-reviewed paper to go with the clips.
Part 1 of 3:
Part 2 of 3:
Part 3 of 3:
And here is the article that discusses the same topic, in more detail, and with footnotes.
Can we be good without God? At first the answer to this question may seem so obvious that even to pose it arouses indignation. For while those of us who are Christian theists undoubtedly find in God a source of moral strength and resolve which enables us to live lives that are better than those we should live without Him, nevertheless it would seem arrogant and ignorant to claim that those who do not share a belief in God do not often live good moral lives–indeed, embarrassingly, lives that sometimes put our own to shame.
But wait. It would, indeed, be arrogant and ignorant to claim that people cannot be good without belief in God. But that was not the question. The question was: can we be good without God? When we ask that question, we are posing in a provocative way the meta-ethical question of the objectivity of moral values. Are the values we hold dear and guide our lives by mere social conventions akin to driving on the left versus right side of the road or mere expressions of personal preference akin to having a taste for certain foods or not? Or are they valid independently of our apprehension of them, and if so, what is their foundation? Moreover, if morality is just a human convention, then why should we act morally, especially when it conflicts with self-interest? Or are we in some way held accountable for our moral decisions and actions?
Today I want to argue that if God exists, then the objectivity of moral values, moral duties, and moral accountability is secured, but that in the absence of God, that is, if God does not exist, then morality is just a human convention, that is to say, morality is wholly subjective and non-binding. We might act in precisely the same ways that we do in fact act, but in the absence of God, such actions would no longer count as good (or evil), since if God does not exist, objective moral values do not exist. Thus, we cannot truly be good without God. On the other hand, if we do believe that moral values and duties are objective, that provides moral grounds for believing in God.
This is the easiest argument for God’s existence to discuss with non-Christians. If you would like to hear a good debate on this topic, I recommend the debate between Arif Ahmed and Glenn Peoples.