Although atheism might have been logically tenable before Darwin, Darwin made it possible to be an intellectually fulfilled atheist.

It is quite true that many scientists, many physicists, maintain that the physical constants, the half dozen or so numbers that physicists have to simply assume in order to derive the rest of their understanding ... have to be assumed. You can't provide a rationale for why those numbers are there. Physicists have calculated that if any of these numbers was a little bit different, the universe as we know it wouldn't exist.

You don't believe that the Earth is round only if you're an astronaut. You don't believe Napoleon existed only if you're a historian. You believe these things because they're facts, proved by evidence.

My passion is for scientific truth. I don't much care about good and evil. ... I care about what's true.

I find that religion really does motivate people to do horrible things because they have this passionate faith in whatever their religion happens to be, and it teaches them that the other religion is the wrong one.

Science replaces private prejudice with public, verifiable evidence.

One of the possible reasons why we might be good is that we're frightened, frightened of God. We want the reward in Heaven, we don't want to go to Hell. That would be an ignoble, ignominious reason for being good, and I think that if anybody was good to you just because they hoped for a heavenly reward, you wouldn't respect them, you'd probably give them a wide berth.