....But since technical explaining and explicability provide the criterion for what can claim to be real, the inexplicable residue left over becomes the superfluous. In this way the mysterious is only what is left over, what is not yet accounted for and incorporated within the circuit of explicative procedures.
It would surely be simplistic and not thoughtful at all if we were saying that the little ego of some individual man were capable of elevating calculability to the rank of the measure of the reality of the real. Instead, the modern age corresponds to the metaphysical depth of the course of its history, when, in accordance with its will toward the unconditional 'residulessness' of all procedure and all organizing, it builds broad avenues through all continents and so no longer has a place free for that residue in which the mystery would still glimmer in the form of mere inexplicability. The secret in the mystery is a kind of concealment, characterized by its insignificance, in virtue of which the mystery is an open one. We readily misuse the term 'open secret' or 'open mystery' and apply it to the situation where there is precisely nothing secret or mysterious at all but where what is already known by everyone is not supposed to be brought ino the open. The 'open mystery' in the genuine and strict sense, on the contrary, occurs where the concealing of the mysterious is simply experienced as concealedness and is lodged in a historically arisen reticence. The openness of the open mystery does not consist in solving the mystery, thus destroying it, but consists in not touching the concealedness of the simple and the essential and letting this concealedness alone in its appearance...
in:
Parmenides
Martin Heidegger
Lectures, University of Freiburg, Winter 1942-1943