The mystics — to give them their short, familiar name — are men and women who insist that they know for certain the presence and activity of that which they call the Love of God. They are conscious of that Fact which is there for all, and which is the true subject-matter of religion; but of which the average person remains either unconscious or faintly and occasionally aware. They know a spiritual order, penetrating, and everywhere conditioning through transcending the world of sense. They declare to us a Reality most rich and living, which is not a reality of time and space; which is something other than everything we mean by “nature,” and for which no merely pantheistic explanation will suffice. These men and women therefore give precision and an objective to that more or less vague thirst for the Infinite and Unchanging which, even in the rudimentary form in which most of us yet possess it, is surely the most wonderful of all possessions; that sense of another and unearthly scale of values pressing in on them; that strange appreciation of, and craving for, an unchanging Reality utterly distinct from themselves which is the raw material of all religion. And it is through the work done by spiritual genius, its power of revealing to others at least something of that which it finds and feels, that average men and women obtain in the long run all their more vivid convictions in respect of the transcendent world; as through the work done by artistic or scientific genius they learn something of the significance and structure of the physical world.
From Man and the Supernatural