Diderot not only did not write comedy in such a style; but he does not even so much as show consciousness that any difference exists between one kind of prose and another.

The blurred phrases and clipped sentences of what Diderot would have called Nature, that is to say of real life, are intolerable on the stage.

Even he felt this, for his characters, though their dialogue is without wit or finish, are still dull and tame of speech, in a different way from that in which the people whom we may meet are dull and tame.

There is an art of a kind, though of an extremely vapid kind.
Again, though he may be right in contending that there is a serious kind of comedy as distinct from that gay comedy which is neighbour to farce--of this we shall see more presently--yet he is certainly wrong in believing that we can willingly endure five acts of serious comedy without a single relieving passage of humour.

Contrast of character, where all the characters are realistic and common, is not enough.