[I]f I am concerned to meet Kant's demands upon any future metaphysics, if I am impressed by Hume's argument that the central science is the empirical science of man, if I respond to Descartes' aspiration for bold yet methodical initiative, these themes from a past that is over are but overtones in the problem that is our existential situation. If its confusion is to be replaced by intelligible order and its violence by reasonable affirmation, then the nucleus from which this process can begin must include an acknowledgment of detached inquiry and disinterested reflection, a rigorous unfolding of the implications of that acknowledgment, an acceptance not only of the metaphysics that constitutes the unfolding but also of the method that guides it between the Charybdis of asserting too little and the Scylla of asserting too much.
--Bernard Lonergan, Insight, Chapter 16.
Every attempt at metaphysical synthesis, especially when it deals with the complex riches of knowledge and of the mind, must distinguish in order to unite. What is thus incumbent upon a reflexive and critical philosophy is above all to discriminate and discern the degrees of knowing, its organization and its internal differentiations.
Jacques Maritain, The Degrees of Knowledge, Preface