Joseph Ratzinger considers the rejection of ontology the underlying motive of the movement of dehellenization which is the cause of the modern intellectual crisis. Nature and Mission of Theology (Ignatius, 1995), 20-21.
That essay, "Faith, Philosophy and Theology" (given in Minnesota in 1984) makes the point that without ontology theology has nothing to say about God or about man because it is deprived of the very ground of truth; and, if ontology is rejected there is no way for faith to express itself to the world. Reason is set aside as being outside of the bounds of faith, so there is no common ground for conversation between believer and non-believer.
Solution:
a. Both faith and philosophy must continue today the fundamental human quest on how to live rightly, and what it means to be a man, theology and philosophy, each within its own competence and in cooperation with each other; the chief question of the age being the relationship between metaphysics and history. "The central concern is the relationship between history and ethos, between human action and the unmanipulable character of reality." 23
b. "[F]aith advances a philosophical, more precisely, an ontological claim when it professes the existence of God." 24 It is a claim regarding the whole of reality which is valid for all men, not just a private opinion.
c. Faith's love of the logos leads to apo-logia, eros for the truth, and the duty, in charity, to spread it, also in human terms, philosophically. "[L]ove for Christ and of one's neighbor for Christ's sake can enjoy stability and consistency only if its deepest motivation is love for the truth." 27