Sporadic great men come everywhere. But for a community to get vibrating through and through with intensely active life, many geniuses coming together and in rapid succession are required. This is why great epochs are so rare, - why the sudden bloom of a Greece, an early Rome, a Renaissance, is such a mystery. Blow must follow blow so fast that no cooling can occur in the intervals. Then the mass of the nation glows incandescent, and may continue to glow by pure inertia long after the originators of its internal movement have passed away. We often hear surprise expressed that in these high tides of human affairs not only the people should be filled with stronger life, but that individual geniuses should seem so exceptionally abundant. This mystery is just about as deep as the time-honored conundrum as to why great rivers flow by great towns. It is true that great public fermentations awaken and adopt many geniuses who in more torpid times would have had no chance to work. But over and above this there must be an exceptional concourse of genius about a time, to make the fermentation begin at all. The unlikeliness of the concourse is far greater than the unlikeliness of any particular genius; hence the rarity of these periods and the exceptional aspect which they always wear.
A genius is the man in whom you are least likely to find the power of attending to anything insipid or distasteful in itself. He breaks his engagements, leaves his letters unanswered, neglects his family duties incorrigibly, because he is powerless to turn his attention down and back from those more interesting trains of imagery with which his genius constantly occupies his mind.
He is a man of capacity who possesses considerable intellectual riches: while he is a man of genius who finds out a vein of new ore. Originality is the seeing nature differently from others, and yet as it is in itself. It is not singularity or affectation, but the discovery of new and valuable truth. All the world do not see the whole meaning of any object they have been looking at. Habit blinds them to some things: shortsightedness to others. Every mind is not a gauge and measure of truth. Nature has her surface and her dark recesses. She is deep, obscure, and infinite. It is only minds on whom she makes her fullest impressions that can penetrate her shrine or unveil her Holy of Holies. It is only those whom she has filled with her spirit that have the boldness or the power to reveal her mysteries to others.