Leo Tolstoy on Art

The presence in various degrees of these three conditions - individuality, clearness, and sincerity - decides the merit of a work of art as art, apart from subject matter. Such are the three conditions which divide art from its counterfeits, and which also decide the quality of every work of art apart from its subject matter.

The absence of any one of these conditions excludes a work form the category of art and relegates it to that of art's counterfeits. If the work does not transmit the artist's peculiarity of feeling and is therefore not individual, if it is unintelligibly expressed, or if it has not proceeded from the author's inner need for expression - it is not a work of art. If all these conditions are present, even in the smallest degree, then the work, even if a weak one, is yet a work of art.

But most of all is the degree of infectiousness of art increased by the degree of sincerity in the artist. As soon as the spectator, hearer, or reader feels that the artist is infected by his own production, and writes, sings, or plays for himself, and not merely to act on others, this mental condition of the artist infects the receiver; and contrariwise, as soon as the spectator, reader, or hearer feels that the author is not writing, singing, or playing for his own satisfaction - does not himself feel what he wishes to express - but is doing it for him, the receiver, a resistance immediately springs up, and the most individual and the newest feelings and the cleverest technique not only fail to produce any infection but actually repel.
I have mentioned three conditions of contagiousness in art, but they may be all summed up into one, the last, sincerity, i.e., that the artist should be impelled by an inner need to express his feeling. That condition includes the first; for if the artist is sincere he will express the feeling as he experienced it. And as each man is different from everyone else, his feeling will be individual for everyone else; and the more individual it is - the more the artist has drawn it from the depths of his nature - the more sympathetic and sincere will it be. And this same sincerity will impel the artist to find a clear expression of the feeling which he wishes to transmit.

Therefore this third condition - sincerity - is the most important of the three. It is always complied with in peasant art, and this explains why such art always acts so powerfully; but it is a condition almost entirely absent from our upper-class art, which is continually produced by artists actuated by personal aims of covetousness or vanity.