Nobel Prize–winning German physicist (1858–1947) who pioneered the understanding of quantum theory. ALS in German, signed “M. Planck,” three pages on two adjoining sheets, 5.5 x 8.75, November 15, 1932. A superb critical letter to Moritz Schlick, Planck’s former student. Planck acknowledges receipt of an advance copy of Schlick’s famous article “Positivism and Realism,” and then proceeds to critique its logic, language, and viewpoint. Planck begins by suggesting that Schlick’s affirmations lead to the illogical conclusion that “something that is not pre-existing can be shown as real through verification of the pre-existing.” He then objects to the use of the term “meaningless” in Schlick’s phrase “the notion of a non-verifiable external world is meaningless,” subtly arguing that the word “non-specifiable” is preferable. Planck concludes by stating that “the positivist point of view surely has its significance…[But] the intentional cannot be removed from philosophy, just like it cannot be removed from any single science.” In fine condition, with a tiny tear to the right edge. As head of the ‘Vienna Circle,’ Schlick was at the center of the ‘logical positivist’ movement to redefine the philosophy of science on the principle of ‘verificationism,’ a viewpoint contending that only empirically or logically verifiable statements are meaningful. Planck was both the founder of quantum theory and one of its most active philosophic voices. Though urbane in tone, Planck’s letter essentially skewers the central tenets of the positivist stance. Remarkable content from the man who laid the groundwork for today’s fundamental scientific theories. RR Auction COA.
