Translated from Italian by me (WTFPL).
I will answer you in good conscience and I will swear to you, that since I set foot in this city, not a single drop of pleasure has fallen upon my soul; except in those moments when I have read your letters, which I tell you without any exaggeration have been the most beautiful moments of my stay in Rome: and those very few lines that you placed beneath my Mother’s letter, were for me like a flash of light breaking through the dense, mute, and desolate darkness that surrounded me. You will say that I do not know how to live; that for you, and for others like you, the fate would not be the same. But listen to my reasoning and to the facts. Man absolutely cannot live in a large sphere, because his strength or capacity for relations is limited. In a small town we may grow weary, but in the end man’s relations to man and to things do exist, because the sphere of those relations is narrow and proportioned to human nature. In a large city, man lives without any relation whatsoever to what surrounds him, because the sphere is so vast that the individual cannot fill it, cannot sense it around himself, and thus there is no point of contact between it and him. From this you may infer how much greater and more terrible is the boredom one feels in a large city than that which one feels in small towns: since indifference – that horrible passion, or rather non-passion, of man – truly and necessarily has its main seat in large cities, that is, in very extensive societies. Man’s sensitive faculty, in these places, is reduced to sight alone. This is the sole sensation of individuals, which in no way reflects inwardly. The only way to be able to live in a large city, and the one which all, sooner or later, are obliged to adopt, is to form for oneself a small sphere of relations, remaining in complete indifference toward all the rest of society. That is to say, to build around oneself a kind of small town within the large one; the rest of the big city remaining useless and indifferent to the individual. […]
Giacomo Leopardi to Carlo Leopardi – Rome, December 6, 1822