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.

Great men are like eagles, and build their nest on some lofty solitude.

That which knows all things and is known by none is the subject.

The cause of laughter is simply the sudden perception of the incongruity between a concept and the real project.

There is one respect in which beasts show real wisdom... their quiet, placid enjoyment of the present moment.

There is no doubt that life is given us, not to be enjoyed, but to be overcome; to be got over.

The intellectual attainments of a man who thinks for himself resemble a fine painting, where the light and shade are correct, the tone sustained, the colour perfectly harmonised; it is true to life. On the other hand, the intellectual attainments of the mere man of learning are like a large palette, full of all sorts of colours, which at most are systematically arranged, but devoid of harmony, connection and meaning.