Truth in art is the unity of a thing with itself: the outward rendered expressive of the inward: the soul made incarnate: the body instinct with spirit. For this reason there is no truth comparable to sorrow.
When he takes the knife to the canvass the servants find him lying dead with a knife through is heart and "withered, wrinkled, and loathsome of visage." and the portrait "in all the wonders of his exquisite youth and beauty." p 349
I am afraid that you have been listening to the conversation of someone older than yourself. That is always a dangerous thing to do, and if you allow it to degenerate into a habit, you will find it absolutely fatal to any intellectual development.