Carl Sagan described the theory of evolution in his final book as the doctrine
that "human beings (and all the other species) have slowly evolved by natural
processes from a succession of more ancient beings with no divine intervention
needed along the way." It is the alleged absence of divine intervention
throughout the history of life—the strict materialism of the orthodox
theory—that explains why a great many people, only some of whom are biblical
fundamentalists, think that Darwinian evolution (beyond the micro level) is
basically materialistic philosophy disguised as scientific fact.

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 counterintuitive, no matter
how mystifying to the uninitiated. Moreover, that materialism is absolute, for
we cannot allow a Divine Foot in the door.