>>1842
Books:
The Scientific Worldview, G. Borchardt
Capital Vol. 1, K. Marx
The Phenomenology of Spirit, G.W.F. Hegel
General ideas:
Kant's phenomena vs noumena problem
German Idealism's discussion of the problem of the subject/object distinction,the problem of knowledge, and the problem of the "world".
Heraclitus' idea of reality being flux and unity of opposites + Whitehead's process philosophy
Eastern absolute monism: Advaita Vedanta
Kierkegaard's concept of despair and the genuine individual
The concept of absolute presuppositions and their role in metaphysics from R.G.Collingwood
Not all of these are relevant to me anymore, but they certainly caused a big change in my way of thinking over time.