Then you missed the post where I said you actually don't have to be both...but atheism loses its grounding without materialism. You can be an atheist and believe in ghosts since ghosts aren't gods.
Originally Posted by Paleobird
At the risk of quoting a bias source, even though the argument is a sound one:
A Catholic Thinker - The Incoherence of Atheism
Materialism is a philosophy that states, simply, that matter is all that exists – period. There is no God because we cannot see Him. There are no human souls because we cannot detect them physically by any means we’re aware of. The philosophy of materialism is the cornerstone of the atheist’s worldview, and a couple large issues can be pointed out about that fact at the outset:
i) Materialism is assumed to be true by nearly all atheists – this is clear from the way they argue. I am not just talking about the run-of-the-mill Dawkins and Hitchens fan but Dawkins and Hitchens themselves. Anyone who argues a philosophical position by essentially assuming what they’re trying to prove is chasing their tale.
ii) Materialism is commonly mistaken for science by these people, who use the two words almost interchangeably (or rather never use “materialism” when they mean “materialism”, because science is something no one can deny). But materialism and true science have nothing in common – science, by the definition that actually virtually everyone accepts, is the study of the natural world. Science itself says nothing at all about things outside the natural world – it doesn’t say that the physical world is all there is, which is what materialism postulates. In reality, atheists use the word “science” to shield materialism, because they are well-aware that materialism is not nearly such an easy sell.
Of course materialism goes very naturally hand-in-hand with atheism: atheism is a direct corollary of materialism. (Although a non-materialistic atheistic worldview is entirely possible, it’s not much accepted. I think one reason is that “giving” on materialism makes the existence of God that much easier – likely – and generally atheists don’t like that.)
Lest anyone (who is not widely educated on these topics) suspect I am misrepresenting the naturalists’ position, here's a quote from famous Harvard biologist Richard Lewontin (emphasis is mine):
"Our willingness to accept scientific claims that are against common sense is the key to an understanding of the real struggle between science and the supernatural. We take the side of science in spite of the patent absurdity of some of its constructs, in spite of its failure to fulfill many of its extravagant promises of health and life, in spite of the tolerance of the scientific community for unsubstantiated just-so stories, because we have a prior commitment, a commitment to materialism. It is not that the methods and institutions of science somehow compel us to accept a material explanation of the phenomenal world, but, on the contrary, that we are forced by our a priori adherence to material causes to create an apparatus of investigation and a set of concepts that produce material explanations, no matter how counter-intuitive, no matter how mystifying to the uninitiated. Moreover, that materialism is absolute, for we cannot allow a Divine Foot in the door."
Note just what he is saying here - atheists are rarely so candid! He is stating directly that:
1) His materialistic philosophy drives his science: he imposes it upon his science, and does not allow the possibility of any conclusion that contradicts this philosophy.
2) The above results not infrequently in constructs that are not just untenable or "against common sense" but downright "patently absurd".
3) It is not at all anything scientific that drives him to materialism: it is his a priori belief/preference.
And we should trust such a person to come up with the correct answers to the great truths of life - why?
Let this quote - which I suspect Dr. Lewontin wishes he'd never put in print - be a lesson to all the disciples of the New Atheists who think they're really guided by science and impartial with regard to evidence. Now, Lewontin implies above that science and materialism are one and the same but that is not at all the case, and that is provable by this simple fact: one can engage in science, using the scientific method, while not accepting materialism.
Would I be putting a grain-feed cow on a fad diet if I took it out of the feedlot and put it on pasture eating the grass nature intended?