Realism and String Theory

The aim of this project is to carry out an investigation of the implications of modern particle physics for the philosophical realism debate. Though physics plays a considerable role in the background of this debate as the prototypical exponent of the natural sciences, its most advanced modern developments like gauge field theory or string theory so far have barely entered the philosophical discussion. We claim that a consideration of those concepts will have important philosophical consequences. While they can be understood as a support for scientific realism in the context of philosophy of science, their most important philosophical implication seems to be the dissolution of the classical realist notion of the ontological object. This double message could shed some new light on the realism debate in general. It is our goal to analyse the impact of modern particle physics on the realism debate and develop a realist approach which is derived from classical physicalist realism but takes into account the modern physical world picture.

The project analyses the implications of string theory for the scientific realism debate. String theory is an attempt to provide a unified theory of elementary particle physics and gravitation. Though string theory still is unlikely to find empirical confirmation anytime soon, it has been playing a central role in fundamental physics for more than two decades. The scientific realism debate is defined by two conflicting positions. The realist assumes that invisible scientific objects like electrons are just as real as the objects of our everyday world. The empiricist, to the contrary, takes scientific objects to be mere theoretical auxiliary constructions and denies their reality. It is argued in the present project that string theory opens up new perspectives on this debate in several ways. On the one hand, the theory`s flourishing without empirical confirmation as well as a number of the theory`s structural properties suggest that the principle of underdetermination of scientific theory building by the available empirical evidence is weakened compared to a classical conception of science. This reduces the plausibility of an empiricist interpretation of string theory. On the other hand, the theory`s mathematical structure is barely compatible with a position of classic realism. The conclusion is drawn that string theory suggests an intermediate position in the realism debate that is akin to the position of structural realism.