There is in the use of a certain kind of abstract language this inconvenience, that the reader may suppose us to be imputing to Diderot a deliberate and systematic survey of the whole movement of his time, and a calculated resolution to further it, now in this way and now in that.  It is not necessary to suppose that the movement as a whole was always present to him.  Diderot’s mind was constantly feeling for explanations; it was never a passive recipient.  The drama excited this alert interest just as everything else excited it.  He thought about that, as about everything else, originally, that is to say, sincerely and in the spirit of reality.[249] Whoever turns with a clear eye and proper intellectual capacity in search of the real bearings of what he is about, is sure to find out the strong currents of the time, even though he may never consciously throw them into their most general and abstract expression.

Since Aristotle, said Lessing, no more philosophical mind than Diderot’s has treated of the theatre.  Lessing himself translated Diderot’s two plays, and the Essay on Dramatic Poetry, and repeatedly said that without the impulse of Diderot’s principles and illustrations his own taste would have taken a different direction.  As a dramatist, the author of Miss Sara Sampson, of Emilia Galotti, and above all that noble dramatic poem, Nathan the Wise, could hardly have owed much to the author of such poor stuff as The Natural Son and The Father of the Family.  Lessing had some dramatic fire, invention, spontaneous elevation; he had a certain measure, though not a very large one, of poetic impulse.  Diderot had nothing of all these, but he had the eye of the philosophic critic.

Any one who reads Lessing’s dramatic criticisms will see that he did not at all overrate his obligations to his French contemporary.[250] It has been replied to the absurd taunt about the French inventing nothing, that at least Descartes invented German philosophy.  Still more true is it that Diderot invented German criticism.

Diderot’s thoughts on the stage, besides his completed plays, and a number of fragmentary scenes, are contained principally in the Paradox on the Player, a short treatise on Dramatic Poetry, and three dialogues appended to The Natural Son.  On the plays a very few words will suffice. The Natural Son must, by me at least, be pronounced one of the most vapid performances in dramatic history.  Even Lessing, unwilling as he was to say a word against a writer who had taught him so much, is too good a critic not to recognise monotony in the characters, stiffness and affectation in the dialogue, and a pedantic ring in the sentences of new-fangled philosophy.[251] Even in the three critical dialogues that Diderot added to the play, Lessing cannot help discerning the mixture of superficiality with an almost pompous pretension.  Rosenkranz, it is true, finds the play rich in fine