"I think, therefore I am is the statement of an intellectual who underrates toothaches. I feel, therefore I am is a truth much more universally valid, and it applies to everything that’s alive. My self does not differ substantially from yours in terms of its thought. Many people, few ideas: we all think more or less the same, and we exchange, borrow, steal thoughts from one another. However, when someone steps on my foot, only I feel the pain. The basis of the self is not thought but suffering, which is the most fundamental of all feelings. While it suffers, not even a cat can doubt its unique and uninterchangeable self. In intense suffering the world disappears and each of us is alone with his self. Suffering is the university of egocentrism."
"I can only say: I love you, F., to the limits of my strength, in this respect you can trust me entirely. But for the rest, F., I do not know myself completely. Surprises and disappointments about myself follow each other in endless succession.What I hope is that these surprises and disappointments will be mine alone; I shall use all my strength to see that none but the pleasant, the pleasantest of surprises of my nature will touch you; I can vouch for this, but what I cannot vouch for is that I shall always succeed. How could I vouch for that in view of the bewildering confusion in my letters which you have been receiving from me all this time? We haven’t been together much, it’s true, but even if we had been together a great deal, I would have asked you (for that would then have been impossible to do) to judge me by my letters and not by your personal experience."