We do, indeed, gain an approximate knowledge of things we have never seen. For example, I have an imperfect notion of a banian-tree, though I have never seen one; but it is only by having seen other trees, and by having also had the perceptions to which appeal is made in describing the peculiarities of the banian. So he who is born blind may learn so much concerning outward objects as the senses of touch, hearing, smell, and taste can impart to him; and he may profit by verbal information to such extent as these perceptions enable him. But the perception itself, and so thought, faith, and in fine all mental experience whatsoever, whether of high order or low, whether relating to objects within us or to objects without, take place only in the privacy of our own minds, and are in their substance not to be transferred. Observe with precision what is here said. The mental experience of each man, if it be of any spiritual depth, has transacted itself in his nature in virtue, to a most important degree, of spiritual relationship with other human beings. There never was an act of development in any man's soul that did not imply a humanity, and involve the virtue of social affinity. I should be dumb, but for the ears of others; I should be deaf, that is, my human ear would be closed, but for human voices; and there is no particle of human energy, and no tint of human coloring, for which we are not, in part, indebted to vital human fellowship. Nevertheless, of this experience, though in the absence of social connection it could not have occurred, not one jot nor tittle can be made over to another by means of words. It can hoist its verbal signal, and the like experience in other souls may interpret the sign; it can do no more. Men may, indeed, _commune_; that is, they may by verbal conference enter mutually into a sense of an already existing unity of inward experience; and there are other and eminent uses of words, of which more anon; but here let it be noted with sufficient emphasis that of minds there can be no mixture, and that speech can make no substantive conveyance of any mental product from one mind to another. Each soul must draw from its native fountains; though we must never forget that without conversation and social relationship its divine thirst would not have been excited. Therefore, in the midst of all warmest and quickest verity of social nearness, there is a kind of sacred and inviolable solitude of the soul. We speak across to each other, as out of different planets in heaven; and the closest intimacy of souls is like that of double stars which revolve about each other, not like that of two lumps of clay which are squeezed and confounded together.