Principles of Philosophy is a book written by René Descartes . In essence, it is a synthesis of the Discourse on Method and Meditations. . The book was primarily intended to replace the Aristotelian modelthen used in French and British universities. The work provides a systematic statement of his metaphysics and natural philosophy , and represents the first general explanation of the mechanistic Universe .
Descartes tried to present, in the form of a textbook, a whole system of thought about the nature of matter, the nature of the mind, and the participation of God in the creation and starting of the Universe.
The book consists of four parts:
The first chapter of Principles of Philosophy deals with metaphysics and issues such as cognition , the sources of human knowledge and understanding, and the relationship between a perfect and omniscient God and human error, both intellectual and moral.
For Descartes Philosophy is the study of wisdom, understood as the ability to conduct human activities; and also as the perfect knowledge of all things that a man can know for the direction of his life, the maintenance of his health, and the knowledge of the arts. Only God is perfectly wise, and man is more or less wise, in proportion to the knowledge he has of the most important truths.
The degrees of knowledge. Descartes identifies four degrees of knowledge, which he names as common knowledge, and a fifth that he designates as the highest. The first degree consists of clear and obvious ideas that can be acquired without even a need for meditation. The second degree is all that knowledge that is learned through the senses. The third is what we learn when we talk to other people. The fourth consists of what we can learn from the writings of people capable of giving good instructions.
The highest knowing. There have been great men throughout time who have sought a better and truer wisdom, a fifth degree of knowledge. This has consisted in the search for the first causes, and those who have followed this search have been called philosophers, but Descartes believes that no one has yet been successful in this task.
Doubt and certainty. Since Plato and Aristotle , there has been a discussion about doubt and certainty . Those who have favored doubt have gone to the extreme of doubting even the most obvious things, and those who have sought certainty have relied excessively on the senses. Although it has been accepted that the senses can deceive us, according to Descartes, no one has yet expressed that the truth cannot be based on the senses, but on the understanding , when it is founded on obvious perceptions.
Meditations on the first philosophy. The search for the first causes or basic truths, as understood by Descartes, is in this work. Explain the metaphysical principles on which the rest of the knowledge can be built.
The tree of philosophy. Philosophy is like a tree, whose roots are metaphysics , its trunk is physics and the branches are the rest of the sciences, mainly medicine , mechanics and morals , which is the last level of sanity . In the same way that the tree has its fruits in its outer parts, the utility of philosophy is also contained in the parts that are learned at the end.
Second part
Part 2 of Principles of Philosophy deals with the general principles of physics and the theory of the laws of motion.
It proposes the principles of nature - the Laws of Physics - seen by Descartes. Above all, it puts forward the principle that, in the absence of external forces, the motion of an object will be uniform and in a straight line. Isaac Newton borrowed this principle from Descartes and included it in his own Principia ; to date it is still called Newton's first law . 2
The third part of Principles of Philosophy is dedicated to astronomical phenomena. His theory of vortexes postulated that space was occupied by an invisible fluid (the ether ) that rotated forming celestial vortices , and the Sun was the center of one of them. This would drag planets, which will be the center of other smaller vortices that would act on satellites like the Moon .
Descartes attacked Copernicus's theories , arguing that bodies that are already in motion remain in motion in a straight line, unless they are deflected. The Cartesian Cosmos was a perfect mechanism created by God that works in a deterministic way without any intervention. Or, as Voltaire put it , it was like a clock that continues to tick eternity since its inception.
This idea was very powerful because it explained how the celestial bodies moved without forces acting at a distance , something inconceivable for the time. The vortex theory was advocated in France for almost a hundred years, even after Isaac Newton . 3 4
The fourth part deals with the properties of minerals, metals, magnets and other natural phenomena and their apprehension through the senses.
Descartes proposed that the magnetic attraction was caused by the circulation of small helical particles , "threaded parts", which circulated through parallel threaded pores in the magnets , through the South pole, the North pole and then through space around the magnet. Back to the south pole. Opposite twisted particles circulated in the opposite direction. When the "threaded parts" approached a lodestone or piece of iron, they passed through its pores, causing a magnetic force.
