 If judging is either acknowledging or rejecting of contents, the notion of acknowledgement/rejection is fundamental in philosophy of mind. In response to Brentano’s move, philosophers at the end of the 19th and beginning of 20th century engaged with his view of acknowledgement. Wilhelm Jerusalem (1895, 67–72) discussed Brentano’s and Marty’s view of judgement and argues for a view of judgement as a complex   activity.[22]  Adolf Reinach (1911, sect. I) distinguished different related notions of ‘acknowledgement’ and criticises Brentano for running them together. Karelitzki (1914) is a (short) monograph devoted to find a plausible concept of acknowledgement and takes Brentano’s as its starting point (see ibid., 13–28). The central figure of the Vienna circle, Moritz Schlick (1925, 50/1974, 43) took Brentano to be right about the psychological nature of judgement, but not its logical role. For this reason he argues against the reduction thesis that we will examine below.