1)Descartes, Leibniz, Berkeley and Hume on the existence of God.
2)Kant on the Transcendental Deduction and the Refutation of Idealism.
3)Spinoza, Hume and Kant on causality.
4)Descartes, Locke and Berkeley on the external world.
5) Hobbes and Locke on the state of nature and the liberty of subjects.