What is called, "Thinking" -- Heidegger

People still hold the view that what is handed down to us by tradition is what in reality lies behind us, while in fact, it comes toward us because we are its captives, and destined to it. The purely historical view of tradition and the course of history is one of those vast self-deceptions in which we must remain entangled as long as we’re still not really thinking.

That self-deception about history prevents us from hearing the language of the thinkers. We do not hear it rightly because we take than language to be mere expression—setting forth the thinker’s views, but the thinker’s language tells what is. To hear it is in no case easy. Hearing it presupposes we meet certain requirements and we do so only on rare occasions.

[To hear the language of the thinkers,] we must acknowledge and respect it. To acknowledge and respect consists of letting every thinker’s thoughts come to us with something, in each case, unique, never to by repeated, inexhaustible and being shaken to the depths by what is un-though in his thought. What is un-thought in a thinker’s thought is not a lack inherent in his thought. What is un-thought in a thinker’s thought is there, in each case only as the un-thought.

The more original the thinking, the richer will be what is un-thought in it. The un-thought is the greatest gift that thinking can bestow. But to the common places of sound common sense, what is un-thought in any thinking always remains merely the incomprehensible, and to the common comprehension, the incomprehensible is never an occasion to stop and look at its own powers of comprehension, still less to notice its limitations.

To the common comprehension, what is incomprehensible remains forever merely offensive. Proof enough that such comprehension, which is convinced that it was born comprehending everything, that it is now being imposed upon with untruth and sham.
The one thing which sound common sense is least capable, is acknowledgment and respect. For acknowledgment and respect call for a readiness to let our own attempts at thinking be overturned again and again by what is un-thought in the thinker’s thought.