Davide Quadrellaro
(ILLC)
### What is Logic? The Psychologismus-Streit and the Modern Reshaping of the Notion of Logic

October 26th at 18:00, in F1.15

What is Logic? Is it an art or a science? Is logic necessarily mathematical? Maybe we got it wrong, maybe logic is an empirical science. As a matter of facts, the idea that logic should not be studied mathematically, but rather considered as a part of psychology was one of the main tenets of many psychologist philosophers, like John Stuart Mill, Theodor Lipps and Christoph Sigwart. In my talk I would like to engage in a genealogical exercise and consider where our (often implicit) views on logic actually come from. In particular, I want to stress the centrality of the debate around psychologism that took place (mainly) in Germany between 1870 and 1914. I think it was through this debate that the notion of logic evolved and started to be seen as something that could be studied mathematically. First, I will introduce the positions of several psychologist philosophers and outline the general framework of the Psychologismus-Streit. Secondly, I will focus on the arguments that Gottlob Frege and Edmund Husserl raised against psychologism. Even if their argument against psychologism are often associated, I think they should be distinguished and related to some very different ways of understanding logic. Finally, I would like to go back to our present times and consider whether all these theories and arguments still have a place in the contemporary debate.