 Regarding formal methods he states: “Mathematical analysis, which is the main means of scientific progress in some areas of natural science, does not play nearly any role at all in others.” (ZK 35, my translation) [“Die mathematische Analyse, die auf manchem Gebiet der Naturwissenschaft das hauptsächliche Mittel des Fortschritt ist, spielt darum bekanntlich auf anderen so gut wie gar keine Rolle.”] Brentano has never made an attempt to introduce formal or mathematical methods in philosophy or psychology. On the contrary, he criticized Johann Friedrich Herbart’s attempts to mathematize psychology, pointing out that Herbart’s mathematical deductions lack empirical foundation and therefore lose contact to the actual phenomena (cf. LW, 36). In another place where he discusses Herbart’s position, he states: “Alas, many believed that where there is so much mathematical rigour, there must be exact science” (GA, 53f, my translation). [“Leider meinten viele, wo so viel mathematische Strenge zu finden sei, müsse exakte Wissenschaft gegeben sein.”] For Brentano, any rigorous, scientific method had to be appropriate for the observed phenomena; his position, thus, is closer to classical empiricism and positivism than to the logical positivism as it was developed in Vienna a decade after his death.