from the materialistic point of view the atheist would try to appeal to evolution to ultimatly explain why we are here. but to explain what our beliefs, ideas, feelings, etc are, they rely on few general theories, all try to reconcile mental terms with physical procceses. i have found one argument that seems to demonstrate the failure of these attempts to any lay person or those unfamiler with philosophy.
according to any of these attempts logically speaking all mental phenomanon must be the same as physical processes of the brain. linguistically this means that the two sentences "i love my daughter" and "i love yellow cake" must mean almost exactically the same thing, let me explain. love becomes synonomous with whatever part of my brain is stimulated at the sight or thought of whatever i love. so yellow cake and my daughter both excite the same part of my brain therefore the word love means the same thing. but ask me what choice i would make if i had to choose between my daughter or yellow cake? bye bye yellow cake.
the problem is that i mean two different things when i use the term love in those two sentences and the physical process can't exaust the meaning of love as i use the term. people just don't mean what the materialist says they mean when they speak. i hope this isn't confusing at all, if it is than please ask me to elaborate.