I am just looking to identify the following rhetorical illusion (or fallacy), if such has been formally recognized. I have noticed that many critics of science and scientific explanations of natural phenomena seek to fill any as-of-yet unproven theories, or missing links, as a sign of the imperfection of science, or even its inadequacy as the authoritative model for explaining natural phenomena. As a predictable next step they explain those phenomena using theories deploying various degrees of mysticism and superstition.
I consider this a fallacy because science is an evolving matter and has not reached a plateau in its findings. So not having an explanation as of yet is by no means a guarantee of eternal mystery. What kind of logical fallacy does this rhetorical tendency fall into?