Pope John Paul II writes:
Having accepted wholeheartedly the Catholic faith, Jacques Maritain understood philosophical investigation to be “a wisdom of reason not closed but open to the wisdom of grace” (Le Philosophe dans la Cite, Paris, 1960, p. 27.)
This spirit of openness and capacity to receive the light of grace led him to the universality of the philosophy of being, the philosophy of the ‘actus essendi,’ whose transcendental value paves the most direct way to rise to the knowledge of ‘Being’ and pure Act, namely to God.
More than any other facet, Jacques Maritain drew attention to this central intuition of the philosophy of Saint Thomas which thus can be called “the philosophy of the proclamation of being,” “a chant in praise of what is” (The Angelicum Address, 1979, no. 6.)
John Paul II, “Letter to Professor Giuseppe Lazzati, Rector of the Universita Cattolica del Sacro Cuore di Milano on the occasion of the centenary of the birth of Jacques Maritain,” in Doctor Communis, vol. XXXVI, no. 1, 1983, pp. 3-5. (Translation by Keith Buersmeyer.)