A foundational discipline
would be a DisCipline?
such that fundamental issues resolved in it have direct and indirect bearing primarily on secondary methodological (see MethodOlogy?
) issues in other disciplines, but the solution of the "fundamental issues" themselves does not depend on the resolution of issues in those other disciplines.
Obviously, it is philosophically tendentious (perhaps betraying a very controversial view in PhiloSophy, namely FoundationalIsm?) to say that there are any foundational disciplines. But for classificatory purposes, it can be useful to regard PhiloSophy and MathematicsAndStatistics--at least--as examples.