[written 1980 when I was 28 • please wait for translation]
The only true theory of knowledge must be able to answer all questions about both knowledge and theory. It must be able to answer all doubts, it must be able to answer the question of whether its own most fundamental premise (if it has one) is really true.
That is, it must be able to prove itself from itself, and at the same time it must also be able to disprove the falsity of all other theories of knowledge. I will honestly admit that this apparently sounds impossible. But it is not impossible. It has not been seen or heard before, but therefore it cannot be impossible. If the reader asks whether I mean by this that I have solved the ultimate problem of epistemology, the most fundamental one, then the answer is: 'Yes'.
The false premise already lies in the very premise expressed in the word 'epistemology.' Epistemology expresses that it is possible to have a 'theory' of cognition, or to put it another way: that it is possible to think about perception! If this is possible, then thinking must be different or separate from perception. What is thinking and what is perception? Note that both concepts, thinking and perception, are both non-dualistic or transcendental in relation to dualistic logic, since they both describe a process. And a process is non-dualistic, for process has no logical opposite! Non-process does not exist in reality, for existence is a process. But I must prove this.
Let us go back to thinking and perception and try to see whether they are really identical or different. But how do we solve this problem? I cannot simply say that one is existential and the other is not, I must at the same time prove that. And I cannot simply say that both thinking and perception are processes without proving this. Has the reader noticed that I have worked and am working with yet another assumption that I have neither mentioned nor proven? What is it?
And it is at first glance difficult to find, because it questions perhaps the greatest taboo that has existed in our culture for the last many thousands of years, namely, I presuppose the existence of I. And I have not proved this assumption. To put it another way, I have assumed that THE THINKER exists. Our culture presupposes precisely that I AM THE THINKER.
And since a theory of knowledge and a true theory of knowledge must be able to answer all possible and thus THINKABLE questions, it must also be able to prove this assumption. And before it can prove this assumption (I am the thinker), it must be able to prove the existence of I. The most fundamental question for a true theory of knowledge must be: AM I?' (only then comes the next question: 'WHO AM I?' — if I could allow myself to distinguish between 'ego' and 'I' it would be clearer, but I cannot at this point in the derivation.)