Meditations on First Philosophy

by

René Descartes

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Meditations on First Philosophy: First Meditation Summary & Analysis

Summary
Analysis
Descartes’s narrator (the Meditator) notes that, as a child, he absorbed lots of ideas that later turned out to be false. He decides that, if he wants to reach any sure scientific knowledge about the world, he must “demolish everything completely and start right again from the foundations.” So he has set some time and space aside to do so in these Meditations.
Descartes’s Meditator points out that most of what people believe is based on received wisdom, not rigorous rational analysis, and he proposes “start[ing] right again from the foundations” of knowledge as an alternative. The First Meditation is arguably the most influential passage in all of Descartes’s writing because it lays out a clear solution to the fundamental question at the heart of his life’s work: how can people be certain about anything? Descartes cares about this problem because it speaks to the fundamental relationship between science and knowledge. In the 17th century, religious faith was generally accepted as the best source of knowledge about the world. But Descartes thought that science was a better alternative, in part because he thought science would definitively prove the basic truths of religion. He also wanted to show that people could achieve absolutely certain knowledge about the natural world around them by analyzing it scientifically. In other words, he proposed that humans should use the scientific method to understand the world. This proposal revolutionized Western science and philosophy forever.
Themes
Knowledge, Doubt, and Science Theme Icon
Intellectual Discipline Theme Icon
Quotes
First, the Meditator will refuse to believe any idea he can’t be completely certain of—meaning anything that he finds it possible to doubt. All his opinions are ultimately based on what he has perceived through his senses. The senses sometimes deceive him, but not about obvious perceptions, like the fact that he’s holding a sheet of paper and sitting next to a fire. That is—unless he’s mad or dreaming. After all, madmen don’t know that their perceptions are false. Neither does the Meditator know when he’s dreaming.
The Meditator wants to start with a certain first principle because he knows that all of science is connected: the basic principles of philosophy are the foundation of physics, which is the foundation for sciences like astronomy, chemistry, and biology, which can in turn explain the basic rules of human psychology and social life. Thus, none of these sciences can be truly reliable unless their philosophical foundation is certain. Doubt and certainty are complementary concepts: by definition, nothing that can be doubted is certain, and something is certain if there is no doubt about it being true. This basic principle of logic leads the Meditator to a foolproof method for identifying what kinds of knowledge are and aren’t certain: if he can logically imagine that something is false, then it isn’t certain. This is how he discards his senses: he argues that, since it’s conceivable that he could be dreaming, he can’t be totally sure that anything he sees, feels, hears, smells, or tastes is real—and so none of these senses can serve as the foundation for his certain science.
Themes
Knowledge, Doubt, and Science Theme Icon
Intellectual Discipline Theme Icon
Quotes
Thus, the Meditator can’t be sure that he’s really awake at all. Nor can he know that his hands and body are even real. But painters imagine things that don’t exist by manipulating shapes that do. Maybe the Meditator’s hands and body don’t exist, but at the very least, they would be the kind of things that do exist. So there must be physical objects with shapes. Numbers, places, and time must also all be real. This suggests that sciences dealing with these basic elements, like math and geometry, can definitely achieve scientific certainty.
This passage is an interesting tangent to the Meditator’s main argument, but it’s easy to misinterpret. The Meditator’s argument about imagination doesn’t mean that, just because he thinks he has hands, there must be hands somewhere in the world—after all, people could easily think they see unicorns, but they still wouldn’t exist. Instead, he’s saying that, because he thinks he has hands and a body, there must be some kind of three-dimensional object somewhere in the world. He also isn’t saying that this knowledge is certain—at least not yet. Rather, he’s just saying that it will be more certain than any other kind of knowledge, if he can prove it to be true. With this argument, Descartes is establishing a basic hierarchy for the sciences: math and geometry are the most fundamental, and by implication, physics comes next.
Themes
Knowledge, Doubt, and Science Theme Icon
Mind and Body Theme Icon
Quotes
Yet the Meditator also believes in an all-powerful God; couldn’t God make it so that even basic math concepts—like the fact that a square has four sides—are actually illusions? In fact, couldn’t the very idea of God be an illusion, too? So in his search for certain truths, the Meditator must abandon the beliefs he had previously taken for granted. To make this easier, it’s helpful to imagine that it’s a “malicious demon” (and not God) who’s deceiving him into thinking that everything he observes actually exists—when it really doesn’t.
The Meditator tests his belief that he can know mathematical principles for certain by coming up with these even more radical thought experiments. The “malicious demon” hypothesis has deeply influenced philosophers for centuries—it’s the foundation for the “brain in a vat” thought experiment commonly used today, as well as for popular stories like the movie The Matrix. Again, the Meditator isn’t seriously arguing that squares don’t have four sides or that God doesn’t exist. Rather, he’s looking for any reason he can find to distrust these basic truths, and then he suspends belief in them in order to find a more certain foundation for his knowledge.
Themes
Knowledge, Doubt, and Science Theme Icon
God and the World Theme Icon
Intellectual Discipline Theme Icon
Quotes
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