The "results" of the history of philosophy do not consist in a catalogue of formulae which can be totted up into a final sum. Instead, they are a series of raids on the deep places of being, carried out according to the possibilities of their own time. The history in which these explorations were made remains a living history, not a dead prehistory. As philosophizing continues, Plato, Aristotle, Thomas do not become prehistory: they remain the originating figures of an enduring approach to the Ground of what is. In their way of thought, and its access to the Origin, a certain aspect of reality, a dimension of being, is caught as in a mirror. None of them is philosophy or the philosopher. It is in the multivalent message of the entire history, and its overall critical evaluation, that truth is disclosed and with it the possibility of fresh knowledge.
Eschatology: Death and Eternal Life, Joseph Ratzinger, Washington, DC, CUA Press, 1988, 23-24.