"It seemed clear to me that life and the world somehow depended upon me now. I may almost say that the world now seemed created for me alone: if I shot myself the world would cease to be at least for me. I say nothing of its being likely that nothing will exist for anyone when I am gone, and that as soon as my consciousness is extinguished the whole world will vanish too and become void like a phantom, as a mere appurtenance of my consciousness, for possibly all this world and all these people are only me myself.
Perhaps it was owing to the terrible misery that was growing in my soul through something which was of more consequence than anything else about me: that something was the conviction that had come upon me that nothing in the world mattered. I had long had an inkling of it, but the full realisation came last year almost suddenly. I suddenly felt that it was all the same to me whether the world existed or whether there had never been anything at all: I began to feel with all my being that there was nothing existing. At first I fancied that many things had existed in the past, but afterwards I guessed that there never had been anything in the past either, but that it had only seemed so for some reason. Little by little I guessed that there would be nothing in the future either. "
Fyodor Dostoyevsky 'The Dream of A Ridiculous Man' (1877)