Descartes’ Proof of Material Things and Rules of Method
Existence of Material Things
Once it has been shown that the thinking subject (*res cogitans*) and God (now infinite) exist, we can show the existence of the world (*res extensa*). To prove its existence, Descartes appeals to the existence of God. This reasoning is as follows: Since God has given me a powerful inclination to believe that the ideas I have come from material things, and God would not be God if He were to deceive me, it is therefore clear that there are things that cause within me the relevant ideas. So, material things exist. (Complete this with the textbook. See below to view pages.)
Specific Rules Exposed by Descartes in *Discourse on the Method*
- Never accept anything as true without knowing with evidence that it is.
- Divide each of the difficulties examined into as many parts as possible and as are required to obtain the best solution.
- Orderly conduct my thoughts, starting with simple objects and easy to learn, to ascend slowly, by degrees, including the knowledge of the most complex.
- To do so in all enumerations so complete and reviews so general as to be sure not to skip anything.
The Criterion of Truth
In the *Discourse on the Method*, the criterion of truth becomes evident, and all probable knowledge is rejected. True knowledge is reached when the evidence is clear and distinct intuition. But this intuition is reached by applying the second rule of the method, which consists of dividing each difficulty into as many parts as possible. The division has a limit, and this limit is the simple natures, captured in a simple and direct understanding (for example, the nature of a triangle). Finding these simple natures is the last step of the analysis and the first of the synthesis.
Synthesis and Deduction
The third rule advises us to conduct orderly thoughts, rising gradually, as if by degrees, to the knowledge of more complex things. This promotion allows us to have, in respect of complex issues, the same security with respect to simple questions, to which we have come to intuition. The third rule is that of synthesis. In reality, this is the time of deduction, the operation by which something can be deduced from another. It is as if on a string, poured into every step of the deduction, the link of one to the following link. In fact, it is a succession of intuitions, as each step of the deduction appears on our minds clear and distinct. Once the deductive process is complete, we need current evidence of the process, but we rely on memory (remember that each step in the process was entirely due course).
We know that the ultimate link in the chain is in connection with the first, although we cannot see with a single glance all the intermediate links together. With them so that we have successively routed and remember that from first to last, each one is linked to its immediate (*Rules*). To achieve this security, we must print, say, a continuous pace of uninterrupted reasoning.
Ensuring Accuracy
The fourth and last rule of *Method* is a board to be sure you have not left anything out or have made any false steps. Although the method is inspired by surveyors, these ideas are based on simple and easy-to-learn concepts to raise themselves through chains of reasoning well-locked up to the issues more complex and difficult to learn.