Materialists share a tendency to want to degrade human beings and our place in the cosmos.
In the situation he describes, it would be a very complacent and foolish detective who took the circumstances as simply natural and failed to ask how they got to be that way.
“The search committee interviewed several apes, three mules, and a tomato plant.”
This is the refrain of the book: “It is all or death!” “All or nothing!” Half-solutions are no solutions at all.
An attribute of a good sci-fi story is that it should open new vistas for the imagination while, at the same time, not requiring the reader to put up with the preposterous.