INTRODUCTION

Carnap was a leading figure of logical empiricism, but he did not begin as a logical empiricist. Hence, it is natural to ask how he became one. This question not only concerns the individual career of a distinguished philosopher, it is significant also for the wider question of how logical empiricism emerged in the general context of European philosophy in the early twentieth century.

Arguably, Carnap began his philosophical career as a neo-Kantian (cf. Coffa, 1991). But, as can be gleaned from his early writings, he was also influenced by scientists and philosophers such as Poincaré, Frege, Hilbert, Russell, Husserl, and Dingler, who did not belong to the Kantian tradition in the strict sense. Presently, the question of who influenced Carnap how is vigorously disputed among Carnap scholars (cf. Pincock, 2002). The aim of this chapter is not to take issue in this debate presenting a new candidate or offering new arguments in favor of one who is already in the race. Rather, I would like to concentrate on an influential factor of a different kind, namely, the influence philosophy of geometry had on Carnap’s philosophy. It is not difficult gathering evidence that philosophy of geometry was important for the early Carnap: his very first work, “Der Raum. Ein Beitrag zur Wissenschaftslehre” (1922), was a treatise on philosophy of geometry.