I think atheism entails philosophical naturalism (PN). That is, were I an atheist, I'd be a PN-er and unashamedly so.
PN is the view that all that is, is material. There are no non-material things. This, spirits and angels and demons do not exist, and of course a non-physical being like God could not exist. "Mind," also, does not exist, as also "free will" does not exist, if by "free" one means some reality that is free of matter and causally affects the physical brain. PN is the view that "reality is exhausted by nature, containing nothing ‘supernatural’,and that the scientific method should be used to investigate all areas of reality, including the ‘human spirit’." ("Naturalism," Stanford Encyclopedia of Philosophy)
OK. But as a PN-atheist I'd have some concerns as regards the logical coherence of PN. For one, PN inwardly contradicts itself. Philosopher David B. Stewart writes:
"If all causes are material in nature— and the vast majority of naturalists believe that all causes are material— then what is the source of human rationality? Concerning this dilemma J. B. S. Haldane wrote, "If my mental processes are determined wholly by the motions of atoms in my brain, I have no reason to suppose that my beliefs are true. . . . And hence I have no reason for supposing my brain to be composed of atoms."
Naturalists want to believe that they are being rational. We see this in the titles they assign to themselves and their publications: "freethinkers," "free inquiry," etc. But in fact their beliefs serve to undermine our confidence in our own rationality. [Emphasis mine. I have always seen PN this way, and nothing I have read over the decades suffices to remove my concerns. So, on PN-atheism, there is no such thing as "freethinking," since "freethinking" is a vestige of something like, e.g., a substance dualism wherein immaterial objects are possible.]
Atheist Patricia Churchland puts it thus: "Boiled down to essentials, a nervous system enables the organism to succeed in the four F's: feeding, fleeing, fighting and reproducing. The principal chore of nervous systems is to get the body parts where they should be in order that the organism may survive. . . . Improvements in sensorimotor control confer an evolutionary advantage: a fancier style of representing is advantageous so long as it is geared to the organism's way of life and enhances the organism's chances of survival. Truth, whatever that is, definitely takes the hindmost."" (Stewart, "The Insufficiency of Naturalism: A Worldview Critique, in William Lane Craig and Paul Copan, Come Let Us Reason: New Essays in Christian Apologetics, Kindle Locations 1639-1649)