I n November 1891, the same month that Arthur became leader of the House of Commons, he gave an inaugural address on the occasion of his installation as lord rector of the University of Glasgow. The title of the printed version was ‘A Fragment on Progress’. It was characteristic of Balfour to call his reflections on the latest research in science or social theory ‘notes’ or ‘comments’ and to pepper his remarks with disclaimers. Yet as his niece pointed out, these wide-ranging, synthetic ruminations were closer to his mental preoccupations than almost any other pronouncements he made. While others revealed themselves in letters, diaries and reminiscences, Arthur did so through published essays that conveyed his thinking about human nature, psychology, religious experience, the origins of social bonds and the prospects for humanity's future. Four years later, when his magnum opus The Foundations of Belief appeared, a reviewer for the Pall Mall Gazette noted that in work like Balfour's ‘a man must, consciously or unconsciously, reveal a great deal of his inner self and his habitual habit of mind’. This could not fail to be of ‘psychological interest as a clue to the deepest convictions and motives of one whose influence upon the political history of the next quarter of a century seems certain to be so great’. Within weeks, in a strange conjunction of events, prosecutor Edward Carson would make the same point about inner selves revealed in writing by using Oscar Wilde's fictional work as legal evidence of the mental proclivities of another player with words whose lucidity mystified the public.

Arthur began ‘A Fragment on Progress’ with his usual ploy of standing up a straw-man that he then exposed to critical attack – a practice he disingenuously attributed to ‘the controversial habits engendered by my unfortunate profession’. In this case he took on the supposedly ‘settled belief’ that ‘there exists a natural law or tendency governing human affairs by which, on the whole, and in the long run, the general progress of our race is assured’. The many historical examples of stagnant societies and extinct civilisations justified no such assumption, he thought, nor did the major theoretical models pretending to explain why it would happen. One of these was evolutionary theory itself.