Reductive materialism is an axiomatic contradiction as it attempts to deny the axiom of consciousness whilst re-affirming it in the process.
While this form of materialism does not explicitly deny consciousness, it does so implicitly by erasing its identity as awareness—redefining it as being a combination of physical processes or matter.
Example
We know, through consciousness, that consciousness is only brain stuff.
Consciousness is being employed as a valid means of awareness, while its distinct status is denied.