He is impervious to reason.

Communists who still insist on following Lenin's ideas are more impervious to reason than many religious people.

Don't bother arguing with it; humans are impervious to logic.

Acacia trees are full of thorns but the mouth of a giraffe is totally impervious to thorns.

Galoshes are impervious to water.

A house that keeps out rain and dew and is impervious to heat and cold is a wonderful thing.