Alec R. Vidler recently remarked that “It is because he was at least two men that Balfour is the most interesting Prime Minister of this century.” He was both a man of political action and a philosopher. In the opinion of Sir Austen Chamberlain, Balfour had “the finest brain that has been applied to politics in our time.” Blanche Dugdale adds that “No one can understand Arthur Balfour who forgets that interest in speculative thinking was part of the fabric of his everyday existence, wherever he was, whatever he was doing.” But no matter that Balfour's involvement in philosophy, theology, science, and psychical research often superseded his active involvement in the affairs of state. The image of a dilettante persists in most biographical studies. One of the reasons for this historiographical problem was stated well in an early biographical sketch:
… Balfour's real achievement as a metaphysician is not easy to determine, and none the more that his fame as a statesman tended to advertise his work with the vulgar and depreciate it with the elect. The former took him at his word and proclaimed him without further ado a philosopher; the latter dismissed him without too much consideration as an amateur.
Whether “vulgar” or “elect,” the public was slow to appreciate the mind of Arthur Balfour. It was not until the publication of his second book, The Foundations of Belief (1895), that Balfour received critical attention as a thinker.