Philosophical conclusions can indeed be established without relying on foundational axioms, as demonstrated by coherentist and non-foundationalist frameworks in metaphysics, ethics, and epistemology.
The claim is specific, empirical, and contestable regarding philosophical methodology (foundationalism vs. coherentism/anti-foundationalism). The retrieved papers include multiple sources arguing for coherentist, non-foundational, or interdependent models in metaphysics and ethics (papers 0, 4, 7), supporting the possibility of philosophical conclusions without an initial axiom. No papers refute the claim.