In 1794 Johann Gottlieb Fichte began to publish Grundlage der gesamten Wissenschaftslehre, the foundation of the entire doctrine of science. Its first paragraph, § 1, is headed Erster, schlechthin unbedingter Grundsatz, first, absolutely unconditioned principle.
In another text of the same year, Fichte described what such a first principle does. Er begleitet alles Wissen, ist in allem Wissen enthalten, und alles Wissen setzt ihn voraus. It accompanies all knowledge, it is contained in all knowledge, and all knowledge presupposes it.