The transformation of φύσις and λόγος into idea and assertion has its inner ground in a transformation of the essence of truth as unconcealment into truth as correctness.
This essence of truth could not be held fast and preserved in its inceptive originality. Unconcealment, the space founded for the appearing of beings, collapsed. “Idea” and “assertion,” οὐσία and κατηγορία were rescued as remnants of this collapse. Once neither beings nor gathering could be preserved and understood on the basis of unconcealment, only one possibility remained: that which had fallen apart and lay there as something present at hand could be brought back together only in a relation that itself had the character of something present at hand. A present-at-hand logos must resemble something else present at hand—beings as the objects of the logos—and be directed by these. To be sure, one last, seeming glimmer of the original essence of ἀλήθεια maintains itself. [The present-at-hand comes forth into unconcealment, and just as necessarily, re-presentational assertion goes forth into the same unconcealment.]104 Yet the seeming glimmer of ἀλήθεια that remains no longer has the sustaining strength and tension to be the determining ground for the essence of truth. And it never became such a ground again. On the contrary. Ever since idea and category have assumed their dominance, philosophy fruitlessly toils to explain the relationship between assertion (thinking) and Being by all possible and impossible means—fruitlessly, because the question of Being has not been brought back to its adequate ground and basis, in order to be unfolded from there.
Now, the collapse of unconcealment, as we briefly call this happening, does not originate from a mere deficiency, from an inability to sustain any longer that which, with this essence, was given to historical humanity to preserve.
104. In parentheses in the 1953 edition.