I should now like to mention a widely current error which prevails with regard to thinking. It is often said that thinking, as it is in itself, is nowhere given to us: the thinking that connects our observations and weaves a network of concepts about them is not at all the same as that which we subsequently extract from the objects of observation in order to make it the object of our study. What we first weave unconsciously into the things is said to be quite different from what we consciously extract from them again.
 Those who hold this view do not see that it is impossible in this way to escape from thinking. I cannot get outside thinking when I want to study it. If we want to distinguish between thinking before we have become conscious of it, and thinking of which we have subsequently become aware, we should not forget that this distinction is a purely external one which has nothing to do with the thing itself. I do not in any way alter a thing by thinking about it. I can well imagine that a being with quite differently constructed sense organs and with a differently functioning intelligence, would have a very different mental picture of a horse from mine, but I cannot imagine that my own thinking becomes something different through the fact that I observe it. I myself observe what I myself produce. Here we are not talking of how my thinking looks to an intelligence other than mine, but of how it looks to me. In any case the picture of my thinking which another intelligence might have cannot be a truer one than my own. Only if I were not myself the being doing the thinking, but if the thinking were to confront me as the activity of a being quite foreign to me, might I then say that although my own picture of the thinking may arise in a particular way, what the thinking of that being may be like in itself, I am quite unable to know.
28] So far, there is not the slightest reason why I should regard my own thinking from any point of view other than my own. After all, I contemplate the rest of the world by means of thinking. Why should I make my thinking an exception?
 I believe I have give sufficient reasons for making thinking the starting point for my study of the world. When Archimedes had discovered the lever, he thought he could lift the whole cosmos from its hinges, if only he could find a point of support for his instrument. He needed something that was supported by itself and by nothing else. In thinking we have a principle which subsists through itself. Let us try, therefore, to understand the world starting from this basis. We can grasp thinking by means of itself. The question is, whether we can also grasp anything else through it.