Truth or coherence? How Adam Smith used philosophical sources to explain how paradigms change

The ‘History of Astronomy’ is fundamental to understanding Smith’s epistemology. The most problematic issue of this text is that Smith intended to analyse the his- tory of astronomy according not to the principles of ‘truth’ that they embodied, but in terms of their logical coherence. However, he was also influenced by Newton’s realism. My thesis is that Smith had no doubts that external reality exists, but be- lieved that it is necessarily filtered by our perceptions and our scientific beliefs. Perceptions and theories do not reflect objective reality as such but reconstruct it according to the procedures and constraints that characterise them. Two generally neglected Smithian sources, Copernicus and Berkeley and ‘Of the External Senses’ seem to legitimize this interpretation. At first sight, Fontenelle used the same argu- ments of Berkeley and Smith, but the difference is that Fontenelle was convinced that astronomical science is characterised by progress toward truth.