I think that an atheist who believes that both humans and dogs are simply animals with no souls would be more likely to value dogs closer to humans than a Christian who believes dogs have no soul but humans do.
Where is this focus on “complexity” coming from?
Where is it written that more complex stuff are more valuable, in a moral sense?
Well, I’m not an atheist and I’m not a practising Christian, but here’s a thought:
To an atheist, we are but a tiny mass on planet Earth which is in turn a tiny speck in a Universe filled with trillions and trillions of stars. How significant can our life be, in the overall scheme of things? How significant can a few electrons going around in your head be in the vast expanses of the Universe?
To a Christian, we are beings created by the Creator of All That Is, and he loves us, each and every one of us. And what we do in this life will affect how we spend the rest of eternity. So, it’s easy to see how a Christian might feel he is important and his life is important.
In general though, I don’t want to turn this into a Christian-vs-atheist treatment of life and death.
I’m curious how 100% atheists deal with questions of life and death.
If you’re curious how Christians deal with these questions, you can start a thread about it.