No man really thinks and feels monotonously. If he is monotonous in his manner of setting forth his thoughts and feelings, that is either because he has not learned the art of writing, or because he is more or less consciously imitating the manner of others. The subtle play of thought will give movement and life to his style if he do not clog it with critical superstitions. I do not say that it will give him grace and power; I do not say that relying on perfect sincerity will make him a fine writer, because sincerity will not give talent; but I say that sincerity will give him all the power that is possible to him, and will secure him the inestimable excellence of Variety.

The Principles of Success in Literature (1865)