We never arrive at fundamental propositions in the course of our investigation; we get to the boundary of language which stops us from asking further… - Ludwig Wittgenstein

Another alternative would have been to give you what’s called a popular-scientific lecture, that is a lecture intended to make you believe that you understand a thing which actually you don’t understand, and to gratify what I believe to be on of the lowest desires of modern people, namely the superficial curiosity about the latest discoveries of science.

You won't — I really believe — get too much out of reading it. Because you won't understand it; the content will seem strange to you. In reality, it isn't strange to you, for the point is ethical. I once wanted to give a few words in the foreword which now actually are not in it, which, however, I'll write to you now because they might be a key for you: I wanted to write that my work consists of two parts: of the one which is here, and of everything which I have not written. And precisely this second part is the important one.

Where two principles really do meet which cannot be reconciled with one another, then each man declares the other a fool and a heretic