Imagination is strong in a man when that particular function of the brain which enables him to observe is roused to activity without any necessary excitement of the sense. Accordingly, we find that imagination is active just in proportion as our sense are not excited by external objects. A long period of solitude, whether in prison or in a sick room; quiet, twilight, darkness-these are the things that promote its activity; and under their influence it comes into play of itself.
Arthur SchopenhauerThe greatest wisdom is to make the enjoyment of the present the supreme object of life; because that is the only reality, all else being merely the play of thought. On the other hand, such a course might just as well be called the greatest folly: for that which in the next moment exists no more, and vanishes utterly, like a dream, can never be worth a serious effort.
Arthur Schopenhauer