The peculiarity of this emotional and sexual life viewed in connection with Leonardo's double nature as an artist and investigator can be grasped only in one way. Of the biographers to whom psychological viewpoints are often very foreign, only one, Edm. Solmi, has to my knowledge approached the solution of the riddle. But a writer, Dimitri Sergewitsch Merejkowski, who selected Leonardo as the hero of a great historical novel has based his delineation on such an understanding of this unusual man, and if not in dry words he gave unmistakable utterance in plastic expression in the manner of a poet.[16] Solmi judges Leonardo as follows: "But the unrequited desire to understand everything surrounding him, and with cold reflection to discover the deepest secret of everything that is perfect, has condemned Leonardo's works to remain forever unfinished."[17] In an essay of the Conferenze Fiorentine the utterances of Leonardo are cited, which show his confession of faith and furnish the key to his character. "_Nessuna cosa si può amare nè odiare, se_ _prima no si ha cognition di quella._"[18] That is: One has no right to love or to hate anything if one has not acquired a thorough knowledge of its nature. And the same is repeated by Leonardo in a passage of the Treaties on the Art of Painting where he seems to defend himself against the accusation of irreligiousness: "But such censurers might better remain silent. For that action is the manner of showing the workmaster so many wonderful things, and this is the way to love so great a discoverer. For, verily great love springs from great knowledge of the beloved object, and if you little know it you will be able to love it only little or not at all."[19] The value of these utterances of Leonardo cannot be found in that they impart to us an important psychological fact, for what they maintain is obviously false, and Leonardo must have known this as well as we do. It is not true that people refrain from loving or hating until they have studied and became familiar with the nature of the object to whom they wish to give these affects, on the contrary they love impulsively and are guided by emotional motives which have nothing to do with cognition and whose affects are weakened, if anything, by thought and reflection. Leonardo only could have implied that the love practiced by people is not of the proper and unobjectionable kind, one should so love as to hold back the affect and to subject it to mental elaboration, and only after it has stood the test of the intellect should free play be given to it. And we thereby understand that he wishes to tell us that this was the case with himself and that it would be worth the effort of everybody else to treat love and hatred as he himself does.