The search for reason ends at the known; on the immense expanse beyond it only the sense of the ineffable can glide. It alone knows the route to that which is remote from experience and understanding. Neither of them is amphibious: reason cannot go beyond the shore, and the sense of the ineffable is out of place where we measure, where we weigh. We do not leave the shore of the known in search of adventure or suspense or because of the failure of reason to answer our questions. We sail because our mind is like a fantastic seashell, and when applying our ear to its lips we hear a perpetual murmur from the waves beyond the shore. Citizens of two realms, we all must sustain a dual allegiance: we sense the ineffable in one realm, we name and exploit reality in another. Between the two we set up a system of references, but we can never fill the gap. They are as far and as close to each other as time and calendar, as violin and melody, as life and what lies beyond the last breath.
Abraham Joshua Heschel, Man Is Not Alone: A Philosophy of Religion. With gratitude to the river.