This article takes its point of departure in a criticism of the views on meta-philosophy of P.M.S. Hacker for being too dismissive of the possibility of philosophical theory-construction. But its real aim is to put forward an explanatory hypothesis for the lack of a body of established truths and universal research programs in philosophy along with the outline of a positive account of what philosophical theories are and of how to assess them. A corollary of the present account is that it allows us to account for the objective dimension of philosophical discourse without taking recourse to the problematic idea of there being worldly facts that function as truth-makers for philosophical claims.