Full Idea
Only if some causal theory of properties is true can it be explained how properties are capable of engaging our knowledge, and our language, in the way they do.
Gist of Idea
Properties must be essentially causal if we can know and speak about them
Source
Sydney Shoemaker (Causality and Properties [1980], §05)
Book Reference
Shoemaker,Sydney: 'Identity, Cause and Mind' [OUP 2003], p.214
A Reaction
Exactly. This also the reason why epiphenomenalism doesn't make sense about consciousness (Idea 7379). The fact that something has causal powers doesn't mean that it just IS a causal power. A bomb isn't an explosion.
Related Idea
Idea 7379 If an epiphenomenon has no physical effects, it has to be undetectable [Dennett]