The Rationalism Of Descartes And Leibniz Essay

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The Rationalism of Descartes and Leibniz

Although philosophy rarely alters its direction and mood with sudden swings, there are times when its new concerns and emphases clearly separate it from its immediate past. Such was the case with seventeenth-century Continental rationalism, whose founder was Rene Descartes and whose new program initiated what is called modern philosophy. In a sense, much of what the Continental rationalists set out to do had already been attempted by the medieval philosophers and by Bacon and Hobbes. But Descartes and Leibniz fashioned a new ideal for philosophy. Influenced by the progress and success of science and mathematics, their new program was an attempt to provide philosophy with the exactness of mathematics. They set out to formulate clear and rational principles that could be organized into a system of truths from which accurate information about the world could be deduced. Their emphasis was upon the rational ability of the human mind, which they now considered the source of truth both about man and about the world. Even though they did not reject the claims of religion, they did consider philosophical reasoning something different than supernatural revelation. They saw little value in feeling and enthusiasm as means for discovering truth, but they did believe that the mind of an individual is structured in such a way that simply by operating according to the appropriate method it can discover the nature of the universe. The rationalists assumed that what they could think clearly with their minds did in fact exist in the world outside their minds. Descartes and Leibniz even argued that certain ideas are innate in the human mind, that, given the proper occasion, experience would cause these innate truths to become self-evident. That the highly optimistic program of rationalism was not altogether successful is indicated in the differences of the systems it produced. These two rationalists finally interpreted the natural world after the mechanical model of physics and believed that determinism was the cause of all physical events. Descartes described reality as a dualism consisting of two basic elements, thought and extension, whereas Leibniz, a pluralist, said that although there is only one kind of substance, the monad, there are nevertheless different kinds of monads accounting for the various elements in nature. In this paper, I will provide a general overview of these two rationalist attempts at creating a formula for truth and raise some of the more common empirical problems that apply to each.

Being a mathematician, Descartes believed that a method was necessary to give his thoughts some structure and a path that could apply to all deductions of truth. In a need for a method, Descartes hypothesized that all men have virtually the same genetic disposition to reason and that the differences in opinion and error in reasoning are due to how that reason is applied. Thus he contends that there is a need for social norms of reason that emulate the certainty of mathematics. “My method,” he writes, “contains everything which gives certainty to the rules of arithmetic.” In it he says that we should never accept anything except clear and distinct ideas, divide each problem into as many parts as are needed to solve it, and always check thoroughly for oversights. If knowledge is to be found without error, he said that it must be by using the principles of clarity and distinctness. In this way he said that knowledge would be indubitable.

To lay the groundwork for this method, Descartes establishes the idea of belief by doubting. He doubts anything that is not self-evident by intuition. A casualty of this doubt is all of his empirical belief. To this end he gives two examples as to why he can’t believe the conclusions drawn using his own senses.

The first of these is the dream argument. The basic layout of the argument for dreaming is that if it’s possible that we are dreaming, we cannot have empirical beliefs. It is possible that we are dreaming, so we can’t have certain knowledge regarding empirical beliefs. To further illustrate his skepticism regarding empirical beliefs, he proposes the purely theoretical “evil demon” argument. In it he argues that if it is possible that we are deceived by an evil god, then we cant know anything with certainty. Since it is possible that we are being deceived by an evil god, then we cannot know with certainty. These arguments were made to establish that it is possible that either through perceptual error or cognitive dysfunction, we may be deceived and not know with certainty.

In light of his newfound credo of doubt and skepticism, he finds himself questioning his very existence. If in fact it is possible that an evil god is tricking him, could it also be possible that he doesn’t really exist at all. To prove his existence he uses the maxim of “Cogito ergo sum”, or “I think therefore I am”. The only thing that could not be doubted is that he thought something, even if it was thinking he was dreaming or being tricked, or thinking that he didn’t have a body. This was what he saw as the first true principle and the basis for any further inquiry. This led him to suppose that the essence of being was thinking, and furthermore, that the mind was separate from the body.

This was a foundation, but it had one problem. It only proved that he existed. He had n