If all our thinking is the result of the firing of nerve synapses…..of cells and molecules……then how then free will? If it is all a pile of natural, chemical processes, then is free will true, or just an illusion? If we have free will, then we can make moral decisions. If we do not have free will, then we can’t make moral decisions. Without free will, then there are no true morals. So in the worldview of those who have nothing but natural processes, we have no basis for morals.
Now, we know naturalists do have morals. But this only makes them inconsistent, sneaking morals in the side door somehow, only without a basis. How does this happen? Because there is a transcendent natural law, of which we cannot escape.