''I think therefore I am''

Western Philosophy in the 17th and 18th century was divided between British Empiricism and Continental Rationalism.

Locke was an Empiricist. An Empiricist was someone who believed that knowledge is only gained through the power of our senses therefore knowledge is gained through experience and not from innate knowledge.

Bacon was also an Empiricist who supported the Scientific Method which means that he avoids the ideas of the mind.

Rationalists, such as: Descartes, Leibniz and Spinoza believed in pure reason, the mind alone, or at least the pre- eminence of the mind.

Both of these theories are ways of attempting to know the truth, neither of these theories are better than the other.

Metaphysics
Materialists believe that material only exists whereas idealism denies existence of matter and that everything is made up of ideas. It is a theory of physics about physics.

Rene Descartes
The first half of the 17th century was contemporary of Galileo which therefore means that it held views similar to Galileo and Bacon etc. in comparison to Aristotelianism and the traditional education available in Universities today.

''I had gained nothing but an increasing recognition of my ignorance.'' (A Socratic idea)

Descartes hoped that a life of action would give him insight but he was disappointed because he embarked on an ambitious plan to search for True Knowledge. He thought that by going back to a point at which no doubt was even possible and then rebuilding human knowledge by unmistakable steps using knowledge that had been tested and was unquestionable.

Descartes was a Christian and therefore uses God and the theory of necessity because your senses can sometimes be deceived which means that it is no more than a status than a dream or a hallucination. E.g 'The Evil Demon'. Descartes' thought of God therefore proves the existence of God since God is perfect which means that his senses are too.

''I exist; I find in my mind the idea of God, who must exist, God being God won't deceive me and hence my belief in an external world is true idea.''

George Berkeley believed that there are just ideas, you can't doubt that you exist or cease to think as to doubt you are thinking.

The Ontological Argument
This argument comes from Kant who believed that existence is a necessary condition for thought, not a result of thought. Does this highlight problems with Dualism? Dualism is the belief that the mind/soul is separate from the body. Descartes believed that they communicated at a specific part of the brain. Materialists rejected this idea because they see matter as fundamental.

Spinoza rejected the Dualism theory since he believed that everything is part of the same substance. Spinoza also didn't believe in Free Will either because humans are not a separate reality, humans are simply aspects of God.