Perelandra's devil – the Un-Man – struck me on first reading as an excellent early depiction of a hostile, alien form of intelligence, superior but purely instrumental. Lewis was very early in working out the implications of that – nowadays the Rationalists and a lot of others would agree that there can be entities with superhuman intelligence that don't intrinsically value their intelligence, and that such beings would have almost irresistible persuasive ability if given the opportunity. (Lewis differs in also giving the Un-Man genuinely supernatural abilities with which it attempts to overawe the protagonist.)
"it regarded intelligence simply and solely as a weapon… Thought was for it a device necessary to certain ends, but thought in itself did not interest it. It assumed reason… externally and inorganically…"
"it regarded intelligence simply and solely as a weapon… Thought was for it a device necessary to certain ends, but thought in itself did not interest it. It assumed reason… externally and inorganically…"