[Olog-hai]

The phrase “as used by philosophers”, as well as that link, continues the argumentum ad verecundiam. Nobody gets to redefine a term into something it is not, at least not without an agenda present—usually a left-wing one.

[who_would_fardels_bear]

Hilarious! If philosophers don't get to choose what terms they use to discuss philosophy among themselves, then who does?

Are scientists not allowed to use the word mass to mean resistance to acceleration because it was used long before to mean an assembly of people or a large body of matter?

Philosophers aren't redefining valid in order to obfuscate. They are limiting the definition to one particular meaning in order to avoid obfuscation.

As a conservative I am against equivocation, obfuscation, and ambiguity.

Are you?