Western Philosophy in the 17th and 16th Centuries was a time where people were divided into two, British empiricism and continental rationalism. Empiricists believe your only source of knowledge is through your senses.
Empiricists such as Locke and Bacon support this idea that knowledge isn’t innate, that we have to experience things to gain an understanding and experience through experiments as we have already learnt through Bacon’s hypothesis.
Rationalists do not look at the evidence but they believe in pure reason. Descartes Leibniz and Spinoza were rationalists.
René Descartes was a major figure in early 17th century philosophy and opposed the empiricists. His idea was to search for true knowledge. Specifically, the focus is on the epistemological project of Descartes' famous work, Meditations on First Philosophy. Descartes defines knowledge in terms of doubt. Descartes' believes in the idea that we have ‘innate ideas’ this was make him a rationalist, tracing back to Plato. Knowledge of the nature of reality derives from ideas of the intellect, not the senses. An important part of metaphysical inquiry therefore involves learning to think with the intellect.
The ontological argument
Descartes developed the ontological argument, suggesting that God is a ‘supremely perfect being. We can tell through the geometry of perfectness that God exists.
They is only one thing we know is true and that is that we exist, even if everything around us is a lie. This is known as the cogito.
Spinoza is known as one of the great rationalists of the 17th century philosophy. He opposed Descartes mind and body dualism. Spinoza argues there is no right and wrong in nature. In Spinoza’s book the ‘Ethics’Spinoza's radical view of God is layed out. God is said to be a substance, with absolutely infinitely many attributes. In Descartes' Principles, he ascribed each substance a 'primary attribute,' of which all its other properties are modifications. For example, a piece of wax has extension as its primary attribute, of which its particular lumpy shape is a modification. Spinoza follows Descartes in holding that extension and thought are attributing, but holds that these are merely the only attributes of which we have any idea.
Leibniz based his theory on substance, like Descartes and Spinoza. But he said there was one substance, this was God. Whereas Descartes believed there were three substances, mind, matter and God.
Leibniz’s best contribution to metaphysics was his theory of the Monads. He believed there is one dominant monad and that is the soul. The Monads are the opposites like
Good vs. evil,
Ying vs. yang.
Feeling well is only the absence of pain
Day is the absence of night.
Leibniz believed that the world exists through necessity.