On the Unfathomableness of Consciousness by Consciousness: Why do   physicists widely agree on the assured extent of their professional   knowledge, but not so philosophers? An exchange of letters with Carl   Friedrich von Weizsaecker
  On the occasion of Carl Friedrich von Weizsaecker's 81st birthday, a colloquium was held on July 3, 1993. One of the topics was "The epistemological foundation of physics from Kant to von Weizsaecker". I took part in the discussion. Afterwards I got the impression that I had not succeeded in making my points clear. Therefore, I wrote an explanatory letter to Prof. von Weizsaecker. This was the beginning of a correspondence on the questions intimated by the title above. In addition, a private discussion between Prof. von Weizsaecker and myself took place. Some readers may be interested in the answers which Carl Friedrich von Weizsaecker has given to the naive questions and views of a physicist with only a rudimentary education in philosophy. The starting point of our discussion was my remark that the conspicuous inability of philosophers to agree on the deepest elements of human existence including the basic questions of ethics, which is tantamount to the occurrence of different schools of philosophy competing with each other, could perhaps be traced back to the fundamental inability of man to attain self-knowledge. Physicists, on the other hand, can reach consent, in an equally remarkable way, on the results of their measurements and on whether or not these results agree with the ideas of theory. They just have to deal with res extensa. Here the yardstick does not intend to measure itself, but objects which are external to it, and this is possible. There remains only the question what consequences can be drawn from this realization. Is philosophy, in as much as it gives statements on the totality of human existence, only an expression of the prevailing social circumstances and views, interesting enough as such, but not a gateway to truth? 
Klaus Gottstein