Abstract

The purpose of this article is to critically assess the ‘three-world theory’ as it is presented—with some slight but decisive differences—by Jürgen Habermas and Karl Popper. This theory presents the philosophy of science with a conceptual and material problem, insofar as it claims that science has no single access to all aspects of the world. Although I will try to demonstrate advantages of Popper’s idea of ‘the third world’ of ideas, the shortcomings of his ontological stance become visible from the pragmatic point of view in Habermas’s theory of communicative acts. With regard to the critique that the three-world theory has met in both its pragmatic and ontological versions, I will take a closer look at John Searle’s naturalistic counter-position. By teasing out some problematic implications in his theory of causation, I aim to show that Searle’s approach is, in fact, much closer to Popper’s than he might think. Finally, while condoning Habermas’s distinction between the natural world and the lifeworld, I will opt for a pragmatically differentiated view of ‘the real’, rather than speaking of different worlds