Propositionen, Sachverhalte und Welt 3

The theory that mental dispositions such as belief and knowledge involve relations between cognitive subjects and propositions or facts is still prevalent (or, rather, is prevalent again) in the philosophy of language and the philosophy of mind. In other words, numerous philosophers from Bolzano to Frege have advocated this theory, but their teachings were reviled and dismissed as metaphysical nonsense by neopositivists 100 years ago. Moreover, when Karl Popper developed his concept of ‘World 3’ by explicitly referencing Bolzano and Frege 50 years ago, he was accused of disregarding the methodological standards of his own critical rationalism. All this seems to have been forgotten, even though we could still learn a lot from this historical background today. This book endeavours to recall these early sources on this subject in order to critically and systematically lay the groundwork for it to be discussed today.