It is a pleasure for me to give this opening address to the Royal Institute of Philosophy Conference on ‘Explanation’ for two reasons. The first is that it is succeeded by exciting symposia and other papers concerned with various special aspects of the topic of explanation. The second is that the conference is being held in my old alma mater, the University of Glasgow, where I did my first degree. Especially due to C. A. Campbell and George Brown there was in the Logic Department a big emphasis on absolute idealism, especially F. H. Bradley. My inclinations were to oppose this line of thought and to espouse the empiricism and realism of Russell, Broad and the like. Empiricism was represented in the department by D. R. Cousin, a modest man who published relatively little, but who was of quite extraordinary philosophical acumen and lucidity, and by Miss M. J. Levett, whose translation of Plato's Theaetetus formed an important part of the philosophy syllabus.

Despite my leaning towards empiricism and realism, I remember having been impressed by Bernard Bosanquet's Implication and Linear Inference. In the main, one must regard this book as a book not on logic but on epistemology. Linear inference is the sort of inference we get in a mathematical proof, but Bosanquet's notion of implication is much closer to the contemporary notion of inference to the best explanation, which Gilbert Harman, who introduced the term, has argued to be the core notion of epistemology. I shall in general be agreeing with Harman here, though I shall not take a stand on the question of whether all inductive reasoning can be so described.