"All his life the example of a syllogism he had studied in Ki..." — Leo Tolstoy quote meaning

All his life the example of a syllogism he had studied in Kiesewetter's logic - "Caius is a man, men are mortal, therefore Caius is mortal" - had seemed to him to be true only in relation to Caius the man, man in general, and it was quite justified , but he wasn't Caius and he wasn't man in general, and he had always been something quite, quite special apart from all other beings; he was Vanya, with Mama, with Papa, with Mitya and Volodya, with his toys and the coachman, with Nyanya, then with Katenka, with all the joys, sorrows, passions of childhood, boyhood, youth. Did Caius know the smell of the striped leather ball Vanya loved so much?: Did Caius kiss his mother's hand like that and did the silken folds of Caius's mother's dress rustle like that for him? Was Caius in love like that? Could Caius chair a session like that? And Caius is indeed mortal and it's right that he should die, but for me, Vanya, Ivan Ilych, with all my feelings and thoughts - for me it's quite different. And it cannot be that I should die. It would be too horrible.