The Science of Knowledge
https://en.wikipedia.org/wiki/Foundations_of_the_Science_of_Knowledge
This book was written in 1794
https://archive.org/details/cu31924014110682
Let science be a building, and let the chief object of this building be firmness. The foundation is firm, and as soon as it is laid down, the object would therefore be attained. But since you can not live on the foundation, nor protect yourself by its means against the arbitrary attacks of enemies, or the unarbitrary attacks of the weather, you proceed to erect walls, and over the walls you build a roof All the parts of the building you connect with the foundation and with each other, and thus the whole gets firmness. But you do not build a building in order to connect the parts; rather you connect the parts in order to make the building firm; and it is firm in so far as all its parts rest upon a firm foundation.
Whatever exists in the human mind, independently of science, we may also call the acts of that mind. These acts are the What which exists; they occur in a certain determined manner, and by this determined manner are they distinguished from each other. This is the How of the What.
The question has been asked. What was I before I became self-conscious? The answer is, I was not at all, for I was not I. The Ego is only, in so far as it is conscious of itself. The possibility of that question is grounded upon a mixing up of the Ego as subject, and the Ego as object of the reflection of the absolute subject ; and is in itself altogether improper. The Ego represents itself, and in so far takes itself up in the form of representation, and now first becomes a somewhat, that is, an object. Consciousness receives in this form of representation a substrate, which is, even without the real consciousness, and which, moreover, is thought bodily. Such a condition is thought, and the question asked. What was the Ego at that time? that is, what is the substrate of consciousness?