 Metaphysical enquiry—the enquiry into being as being—is, Maritain says, a mystery; being is, for example, something that is “pregnant with intelligibility” and too “pure for our intellect” (Preface to Metaphysics, 1934 [1939: 4]). Nevertheless, the mystery of being is an “intelligible mystery” (1934 [1939: 83]), and Maritain holds that, unless one does metaphysics, one cannot be a philosopher; “a philosopher is not a philosopher unless he is a metaphysician” (Existence and the Existent, 1947 [1948: 29]).