Between psychology and physics: Schlick’s Philosophy of Time

Sanne Stuur

Radboud University, Nijmegen

In this paper an attempt is made at an integrated account of Moritz Schlick’s philosophy of time. In particular, we attempt to reconstruct Schlick’s ideas about the relationship between time’s objective features and the subjective experience thereof. In order to do so, it is not enough to look at Schlick’s often studied and cited works on the Theory of Relativity (“Die Philosophische Bedeutung des Relativitätsprinzips” (1915), and ”Raum und Zeit in der gegenwärtigen Physik. Zur Einführung in das Verständnis der allgemeinen Relativitätstheorie“ (1917)). In this paper special attention is paid to Schlick’s earlier works on the relation of philosophy to the sciences. Furthermore, we examine Schlick’s (yet unpublished) correspondence in the years leading up to the publication of his two relativity papers (as it can be found in the Wiener Kreis Archives in Haarlem, The Netherlands). From these sources, a subtle and sophisticated account of the task of philosophy with regards to time emerges. As is well known, Schlick criticized the positivistic and neo-Kantian attempts at making Einstein’s theory of relativity appear dependent entirely on experience or on a priori principles. Furthermore, it is commonly known that Schlick, like Einstein, denied that the concept of time (or that space) had any special dependency on human experience or cognition in comparison with the other concepts or principles of this theory. What is less well known is that Schlick nonetheless believed that time had special subjective, qualitative features that were in principle irreducible to time’s objective properties. Moreover, he believed that is was the task of philosophy precisely – not psychology – to give an account of these subjective elements and show how they relate to and differ from objective time. As such, philosophy ought to not be solely concerned with explicating the foundations of the natural sciences, but should also consider what the natural sciences cannot explain and integrate this with the findings of science. As such, a hiatus in the scholarship on Schlick’s (earlier) philosophy is filled. By taking time as an example of a topic that concerned Schlick throughout his career, we can start to construe a more complete account of Schlick’s philosophical development, including the motivations drove him from the study of physics to the study of philosophy. We can see that Schlick pointed out how philosophy ought to be concerned with the foundations of the natural sciences, yet how the task of philosophy did not completely coincide with this, and which things Schlick considered to be of philosophical significance and value beyond those. Thus, we get a better understanding of the philosophical orientation and background of one of the founding figures of logical empiricist movement.