It is possible, in the daily intercourse of living, to be familiar with every detail of a man’s behaviour and habits, and yet to understand nothing of the man himself; or in history, to wade through volumes about some figure or movement, and yet not to be any closer to the reality. Then, suddenly, one chances upon a formula, a character-equation, which explains all, which renders coherent and intelligible what had before been isolated and inexplicable problems of history or of personal acquaintance.

Let me illustrate. For years I had known a certain man of my own age and profession, conversed with him, studied with him, idled with him. Now, after all this I never became intimate with him, as it is a commonplace that knowledge may never ripen into friendship. Here familiarity never developed even into knowledge. The springs and fountains of the man’s conduct were completely hidden from me. We had exchanged a thousand views with each other, but we had never exchanged ourselves. All the time I felt dimly that there was some lack, some defect, which precluded intimacy. For four or five years our relations stood thus, our good fellowship more apparent than real, when, quite unexpectedly from nowhere, a character-formula (I cannot think of a more apt word) flashed upon me.

There had been nothing to indicate any ground for our divergence, when one day my demon or my angel whispered : not in what he did, not in what he said, but in what he left unsaid will you find an answer.