A.I., Scientific Discovery and Realism∗

Abstract. Epistemologists have debated at length whether scientific discovery is a rational and logical process. If it is, according to the Artificial Intelligence hypothesis, it should be possible to write computer programs able to discover laws or theories; and if such programs were written, this would definitely prove the existence of a logic of discovery. Attempts in this direction, however, have been unsuccessful: the programs written by Simon’s group, indeed, infer famous laws of physics and chemistry; but having found no new law, they cannot properly be considered discovery machines. The programs written in the ‘Turing tradition’, instead, produced new and useful empirical general-ization, but no theoretical discovery, thus failing to prove the logical character of the most significant kind of discoveries. A new cognitivist and connectionist approach by Holland, Holyoak, Nisbett and Thagard, looks more promising. Reflection on their proposals helps to understand the complex character of discovery processes, the abandonment of belief in the logic of discovery by logical positivists, and the necessity of a realist interpretation of scientific research. 1. The Problem of Scientific Discovery Is scientific discovery a rational activity, is there a method for it, or a “logic ” to be followed? There has been a long debate on this question among philosophers of science, with people like Francis Bacon, John Stuart Mill and Hans Reichen-bach answering “yes”, and no less important characters, such as William Whewell