Their metaphysics allows for no mind or intelligence behind it all nor, they insist, is there any reason or evidence for supposing that any such non-material, non-natural intelligence exists.
William J. Murray offers a dissenting view in a comment at Uncommon Descent. He poses an interesting thought experiment.
Suppose we landed on a planet in a different star system, and on an otherwise barren planet we found a massive, self-sustaining and self-replicating metallic machine comprised mainly of alloyed materials found nowhere else on the planet other than as a material manufactured by the machine for it’s own duplication and repair, what would be the materialist’s reaction?At the very least anyone in this situation would have good reason for supposing that some non-human intelligence had been at work on that planet. But we ourselves are in an analogous situation on this planet since we are surrounded by much the same sort of machines, albeit biological machines, as Murray describes.
Further, what if the machine was run by a library of code and a code-processing system?
Would they accept the machine as evidence of non-human intelligent design? If they found no archaeological evidence on the planet supporting the idea that an intelligent race of beings at any time in history constructed that machine, would they turn to naturalistic explanations? Would they insist that somehow humans had been there before and left the machine without any other trace of their presence?
Or, would they come to the conclusion that an intelligent agency of some sort designed and built the machine, even though they didn’t know what that intelligent agency was?
Or consider the fine-tuning of the universe:
[W]hat if we were exploring space in distance areas of the galaxy and came across a habitat floating in space, perfectly balanced to be self-supporting for a rich and diverse spectrum of life. Let’s say this habitat is enclosed by some form of unknown energy with no apparent source. Everything in the habitat is finely tuned for the flourishing and preservation of that life.Of course they would unless they were so obsessively determined to avoid that conclusion, unless they found that conclusion so repugnant that they'd refuse to accept it no matter how much evidence were available to them. But then, of course, they would be behaving irrationally, perhaps even insanely.
Would the materialist conclude that there must be countless other such habitats floating around, produced by some as yet unknown unintelligent process, each tuned differently and most not capable of supporting life? Or, would they conclude that some intelligent agency must have designed and built the habitat for the purpose of sustaining life? Would they insist other humans must have built it? Would they ever even imagine that a non-human intelligence might be responsible?
One might conclude that the materialist's refusal to accept the evidence that Murray describes is motivated by fear of what that evidence points to.
Murray again:
[M]aterialists contort themselves as if they are headed toward some horrible, painful experience simply by admitting this [that the universe appears to be intelligently designed].Good questions. What are they afraid of?
They do similar such contortions when confronted by the hard problem of consciousness and the problem of subjective morality, when admitting that objective morality must exist, and admitting that consciousness exists beyond the material, commits them to no [particular] spiritual or religious doctrine whatsoever. It’s just admitting what evidence indicates and what is logically necessary....
Why fight it tooth and nail? Why contort, obfuscate, and run from these things? Why deny the obvious and the logical to the point of saying such foolish things like “consciousness is an illusion” or “morality is subjective”, when they cannot even act or speak as if such things are true?