In writing style The Confessions of a Young Man is presented as a novel, with a hero named Dayne, but the reader assumes in essence it is an autobiography, a true "confession". Dayne (i.e. Moore) went to Paris as a teenager, and almost becomes a full Parisian nearly forgetting the English language after 15 years. He sketches, with a frankness now jubilant, now cynical, the luscious "vie de Boheme" that Paris alone could offer the young man of health and wealth who loved art. Amid scenes splendid, squalid, or bizarre, move students, cabotins, painters, poets, pale enthusiasts starving for the sake of an idea, actresses, women of fashion, courtesans, clubmen, and spectators. Artistic endeavour and perfumed vice mingle in fraternity; everything is unusual, irregular, fantastic. Dayne emerges from the ordeal of this environment but little changed. For him the enticements of the flesh are not more powerful than those of art. One week he is beguiling the hours in some salon or alcove, the next he is incandescent with aspiration. So the years pass; and at last, having saturated himself with the French theories of literary and graphic art which are bound up with the names of Flaubert, Goncourts, Zola, Degas, and Manet, he one day learns with tragic certainty that he is not destined to be a painter, and he courageously admits that all this periodic, frenzied effort has been misdirected. Then we have interludes of philosophy and literary criticism; the philosophy perhaps not of much account; the criticism often original, epigrammatic, sometimes of an astounding penetration, and always literary. Later, Dayne is driven by adverse circumstances to London and to a lodging in the Strand, where the book ends. Dayne's ideas about art and his temperament can be seen in characteristic passages like the following: "For art was not for us then as it is nowâa mere emotion, right or wrong only in proportion to its intensity; we believed then in the grammar of art, perspective, anatomy, and la jambe qui forte."

Question: What did the confessor believe in the grammar of?
Answer: The grammar of art
Alternative answer: art, perspective, anatomy, and la jambe qui forte