The first fact we learn from observing the action of the mind, when thus severed from communication with the external world, is its perfect independence, its entire unconsciousness of its loss, its capacity to create a world for itself and live a life of its own. If such a condition could be imagined as a mind continuing to live in a dead body, we might find in this phenomenon of sleep how the mind could exist in the same state of activity as now, feel the same emotions of pleasure and of pain, and enjoy a life as real to itself, although imaginary in fact, as is the actual existence of any living man. But it teaches a lesson yet more important. If the mind can thus live a life of its own when severed from the influences of the body by the paralysis of a section of the brain in sleep, is not the presumption strong that this _something_ that does not sleep with the body, that preserves an individual consciousness, that has memory and a Will, can create a world of its own and live and act in it with entire belief in its reality and which has a perfect sense of pleasure and of pain, is not the material brain merely, but something other than brain and of which the brain hemispheres are only the material mechanism? If the Conscious Self lives and works thus when the body is dead to it in sleep, may it not well be—(nay, does it not suggest even a probability?)—that when permanent severance by death is substituted for the temporary severance by sleep, the same Conscious Self may continue to exist with other perceptive and receptive powers adapted to its changed conditions of being? Why, then, are we in dream so credulous as to believe implicitly that whatever visions are presented to us by the busy fancy are realities? Why do we accept impossibilities and incongruities without a question of their truth and scarcely with a sense of surprise or wonder? We have seen that it is _not_ because the _reasoning_ faculties are asleep,—for often they are very active in dream. Simply, it is because we accept as real and as having been sense-conveyed, and therefore as representing external objects, the ideas that are in fact created by the mind itself. And wherefore do we thus accept them? The answer throws a flood of light upon the Mechanism of Mind and the Mechanism of Man. All our sensations are mental. Whether self-created within or brought from without by the senses, we are conscious only of the _mental_ impression. That alone is _real_ to us. That alone _exists_ for us. But by what faculty do we, in the waking state, distinguish between the self-created and the sense-borne ideas and impressions, so as to recognise the former as ideal and the latter as real?