Daniel Cohnitz

In their paper, ‘When are thought experiments poor ones?’ (Peijnenburg and David Atkinson, 2003, Journal of General Philosophy of Science 34, 305-322.), Jeanne Peijnenburg and David Atkinson argue that most, if not all, philosophical thought experiments are “poor” ones with “disastrous consequences” and that they share the property of being poor with some (but not all) scientific thought experiments. Noting that unlike philosophy, the sciences have the resources to avoid the disastrous consequences, Peijnenburg and Atkinson come to the conclusion that the use of thought experiments in science is in general more successful than in philosophy and that instead of concocting more “recherché” thought experiments, philosophy should try to be more empirical. In this comment I will argue that Peijnenburg’s and Atkinson’s view on thought experiments is based on a misleading characterization of both, the dialectical situation in philosophy as well as the history of physics. By giving an adequate account of what the discussion in contemporary philosophy is about, we will arrive at a considerably different evaluation of philosophical thought experiments. For I am convinced that we now find ourselves at an altogether decisive turning point in philosophy, and that we are objectively justified in considering that an end has come to the fruitless conflict of systems. We are already at the present time, in my opinion, in possession of methods which make any such conflict in principle unnecessary. What is now required is their resolute application. (Schlick, ‘The Turning Point in Philosophy’, 1930/1959, p. 54)

One of the most basic methods of philosophy is, and has always been, the consideration of counterfactual cases and imaginary scenarios. One purpose of doing so obviously is to test our theories against such counterfactual cases. Although this method is widespread, it is far from being commonly accepted. Especially during the last two decades it has been confronted with criticism ranging from complete dismissal to denying only its critical powers to a cautious defense of the use of thought experiments as counterexamples. One of the strongest criticisms of the method of thought experimentation is "modal skepticism" as explicated and defended by Peter van Inwagen. Van Inwagen argues that the philosopher's notion of logical possibility is confused and that its epistemology is dubious. I argue that van Inwagen's skepticism is unwarranted. There is a sufficiently clear notion of logical possibility and a sufficiently straightforward way of getting to know what is logically possible. In the remainder of the paper I show how that connects with the methodology of thought experimentation in philosophy.