The World (Descartes)
Encyclopedia
The World, originally titled Le Monde and also called Treatise on the Light, is a book by René Descartes
(1596–1650). Written between 1629 and 1633, it contains a relatively complete version of his philosophy
, from method, to metaphysics
, to physics
and biology
.
Descartes was a follower of the mechanical philosophy
, a form of natural philosophy
popular in the 17th century. He thought everything physical in the universe to be made of tiny "corpuscles" of matter. Corpuscularianism
is a viewpoint closely related to atomism
. The main difference was that Descartes maintained that there could be no vacuum, and all matter was constantly swirling to prevent a void as corpuscles moved through other matter. The World presents a corpuscularian cosmology in which swirling vortices explain, among other phenomena, the creation of our solar system
and the circular motion of planets around the Sun
.
The work endorsed the Copernican view of the moving earth, so Descartes cautiously delayed its release when he heard of the condemnation of Galileo’s Copernicanism by the Catholic Church in Rome
and the subsequent burning of the related works. Descartes discussed his work on the book, and his decision not to release it, in correspondence with another philosopher, Marin Mersenne
. Some material from The World was revised for publication as Principia philosophiae or Principles of Philosophy
(1644), a Latin textbook at first intended by Descartes to replace the Aristotelian textbooks then used in universities. In the Principles the Copernican tone was softened slightly with a relativist frame of reference. The last chapter of The World was published separately as De Homine (On Man) in 1662. The rest of The World was finally published in 1664, and the entire text in 1677.
According to Descartes, the motion, or agitation, of these particles is what gives substances their properties (i.e. their fluidity and hardness). Fire is the most fluid and has enough energy to render most other bodies fluid whereas the particles of air lack the force necessary to do the same. Hard bodies have particles that are all equally hard to separate from the whole.
Based on his observations of how resistant nature is to a vacuum, Descartes deduced that all particles in nature are packed together such that there is no void or empty space in nature (however, Descartes makes it clear that he does not claim that a void cannot exist in nature, since he lacks the observations necessary to say this with certainty).
Descartes describes substances as consisting only of three elementary elements: fire, air and earth, from which the properties of any substance can be characterized by its composition of these elements, the size and arrangement of the particles in the substance, and the motion of its particles.
1) “…each particular part of matter always continues in the same state unless collision with others forces it to change its state.”
2) “…when one of these bodies pushes another, it cannot give the 2nd any motion, except by losing as much of its own motion at the same time…”
3) “…when a body is moving…each of its parts individually tends always to continue moving along a straight line”
(Gaukroger)
As to the reason why heavy objects on Earth fall, Descartes explained this through the agitation of the particles in the atmosphere. The particles of the aether have greater agitation than the particles of air, which in turn have greater agitation than the particles that compose terrestrial objects (e.g. stones). The greater agitation of the aether forces the particles of air from escaping into the heavens, just as the agitation of air particles forces terrestrial bodies, whose particles have far less agitation than those of air, to descend towards the Earth.
1) Light extends circularly in all direction from luminous bodies
2) Light extends out to any distance
3) Light travels instantaneously
4) Light travels ordinarily in straight lines or rays
5) Several rays can come from different points and meet at the same point
6) Several rays can start at the same point and travel in different directions
7) Several rays can pass through the same point without impeding each other
8) If the rays are of very unequal force, then they can sometimes impede one another
9) and 10) Rays can be diverted by reflection or by refraction
11) and 12) The force of a ray can be augmented or diminished by the disposition of the matter that receives it.
René Descartes
René Descartes ; was a French philosopher and writer who spent most of his adult life in the Dutch Republic. He has been dubbed the 'Father of Modern Philosophy', and much subsequent Western philosophy is a response to his writings, which are studied closely to this day...
(1596–1650). Written between 1629 and 1633, it contains a relatively complete version of his philosophy
Philosophy
Philosophy is the study of general and fundamental problems, such as those connected with existence, knowledge, values, reason, mind, and language. Philosophy is distinguished from other ways of addressing such problems by its critical, generally systematic approach and its reliance on rational...
, from method, to metaphysics
Metaphysics
Metaphysics is a branch of philosophy concerned with explaining the fundamental nature of being and the world, although the term is not easily defined. Traditionally, metaphysics attempts to answer two basic questions in the broadest possible terms:...
, to physics
Physics
Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
and biology
Biology
Biology is a natural science concerned with the study of life and living organisms, including their structure, function, growth, origin, evolution, distribution, and taxonomy. Biology is a vast subject containing many subdivisions, topics, and disciplines...
.
Descartes was a follower of the mechanical philosophy
Mechanism (philosophy)
Mechanism is the belief that natural wholes are like machines or artifacts, composed of parts lacking any intrinsic relationship to each other, and with their order imposed from without. Thus, the source of an apparent thing's activities is not the whole itself, but its parts or an external...
, a form of natural philosophy
Natural philosophy
Natural philosophy or the philosophy of nature , is a term applied to the study of nature and the physical universe that was dominant before the development of modern science...
popular in the 17th century. He thought everything physical in the universe to be made of tiny "corpuscles" of matter. Corpuscularianism
Corpuscularianism
Corpuscularianism is a physical theory that supposed all matter to be composed of minute particles, which became important in the Seventeenth century. Among the leading corpuscularians were Rene Descartes, Robert Boyle, and John Locke....
is a viewpoint closely related to atomism
Atomism
Atomism is a natural philosophy that developed in several ancient traditions. The atomists theorized that the natural world consists of two fundamental parts: indivisible atoms and empty void.According to Aristotle, atoms are indestructible and immutable and there are an infinite variety of shapes...
. The main difference was that Descartes maintained that there could be no vacuum, and all matter was constantly swirling to prevent a void as corpuscles moved through other matter. The World presents a corpuscularian cosmology in which swirling vortices explain, among other phenomena, the creation of our solar system
Solar System
The Solar System consists of the Sun and the astronomical objects gravitationally bound in orbit around it, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago. The vast majority of the system's mass is in the Sun...
and the circular motion of planets around the Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
.
The work endorsed the Copernican view of the moving earth, so Descartes cautiously delayed its release when he heard of the condemnation of Galileo’s Copernicanism by the Catholic Church in Rome
Rome
Rome is the capital of Italy and the country's largest and most populated city and comune, with over 2.7 million residents in . The city is located in the central-western portion of the Italian Peninsula, on the Tiber River within the Lazio region of Italy.Rome's history spans two and a half...
and the subsequent burning of the related works. Descartes discussed his work on the book, and his decision not to release it, in correspondence with another philosopher, Marin Mersenne
Marin Mersenne
Marin Mersenne, Marin Mersennus or le Père Mersenne was a French theologian, philosopher, mathematician and music theorist, often referred to as the "father of acoustics"...
. Some material from The World was revised for publication as Principia philosophiae or Principles of Philosophy
Principles of Philosophy
Principles of Philosophy is a book by René Descartes. Written in Latin, it was published in 1644 and dedicated to Elisabeth of Bohemia, with whom Descartes had a long standing friendship. A French version followed in 1647. It set forth the principles of nature—the Laws of Physics--as Descartes...
(1644), a Latin textbook at first intended by Descartes to replace the Aristotelian textbooks then used in universities. In the Principles the Copernican tone was softened slightly with a relativist frame of reference. The last chapter of The World was published separately as De Homine (On Man) in 1662. The rest of The World was finally published in 1664, and the entire text in 1677.
The Void and Particles in Nature
Before Descartes begins to describe his theories in physics, he introduces the reader to the idea that there is no relationship between our sensations and what creates these sensations, thereby casting doubt on the Aristotelian belief that such a relationship existed. Next he describes how fire is capable of breaking wood apart into its minuscule parts through the rapid motion of the particles of fire within the flames. This rapid motion of particles is what gives fire its heat, since Descartes claims heat is nothing more than just the motion of particles, and what causes it to produce light.According to Descartes, the motion, or agitation, of these particles is what gives substances their properties (i.e. their fluidity and hardness). Fire is the most fluid and has enough energy to render most other bodies fluid whereas the particles of air lack the force necessary to do the same. Hard bodies have particles that are all equally hard to separate from the whole.
Based on his observations of how resistant nature is to a vacuum, Descartes deduced that all particles in nature are packed together such that there is no void or empty space in nature (however, Descartes makes it clear that he does not claim that a void cannot exist in nature, since he lacks the observations necessary to say this with certainty).
Descartes describes substances as consisting only of three elementary elements: fire, air and earth, from which the properties of any substance can be characterized by its composition of these elements, the size and arrangement of the particles in the substance, and the motion of its particles.
Descartes' Laws of Motion
The motion of these particles and all other objects in nature are subject to the laws of motion Descartes had observed:1) “…each particular part of matter always continues in the same state unless collision with others forces it to change its state.”
2) “…when one of these bodies pushes another, it cannot give the 2nd any motion, except by losing as much of its own motion at the same time…”
3) “…when a body is moving…each of its parts individually tends always to continue moving along a straight line”
(Gaukroger)
Descartes' Universe
Descartes elaborates on how the universe could have started from utter chaos and with these basic laws could have had its particles arranged so as to resemble the universe we observe today. Once the particles in the chaotic universe began to move, the overall motion would have been circular because there is no void in nature, so whenever a single particle moves, another particle must also move to occupy the space where the previous particle once was. This type of circular motion, or vortex, would have created what Descartes observed to be the orbits of the planets about the sun with the heavier objects spinning out towards the outside of the vortex and the lighter objects remaining closer to the center. To explain this, Descartes used the analogy of a river that carried both floating debris (leaves, feathers, etc.) and heavy boats. If the river abruptly arrived at a sharp bend, the boats would follow Descartes third law of motion and hit the shore of the river since the flow of the particles in the river would not have enough force to change the direction of the boat. However, the much lighter floating debris would follow the river since the particles in the river would have sufficient force to change the direction of the debris. In the heavens, it’s the circular flow of celestial particles, or aether, that causes the motion of the planets to be circular.As to the reason why heavy objects on Earth fall, Descartes explained this through the agitation of the particles in the atmosphere. The particles of the aether have greater agitation than the particles of air, which in turn have greater agitation than the particles that compose terrestrial objects (e.g. stones). The greater agitation of the aether forces the particles of air from escaping into the heavens, just as the agitation of air particles forces terrestrial bodies, whose particles have far less agitation than those of air, to descend towards the Earth.
Descartes' Theory on Light
With his laws of motion set forth and the universe operating under these laws, Descartes next begins to describe his theory on the nature of light. Descartes believed that light traveled instantaneously - a common belief at the time – as an impulse across all the adjacent particles in nature, since Descartes believed nature was without a void. To illustrate this, Descartes used the example of a stick being pushed against some body. Just as the force which is felt at one end of the stick is instantly transferred and felt at the other end, so is the impulse of light that is sent across the heavens and through the atmosphere from luminous bodies to our eyes. Descartes attributed light to have 12 distinct properties:1) Light extends circularly in all direction from luminous bodies
2) Light extends out to any distance
3) Light travels instantaneously
4) Light travels ordinarily in straight lines or rays
5) Several rays can come from different points and meet at the same point
6) Several rays can start at the same point and travel in different directions
7) Several rays can pass through the same point without impeding each other
8) If the rays are of very unequal force, then they can sometimes impede one another
9) and 10) Rays can be diverted by reflection or by refraction
11) and 12) The force of a ray can be augmented or diminished by the disposition of the matter that receives it.
Contents of The World
- On the Difference Between our Sensations and the Things That Produce Them
- In What the Heat and Light of Fire Consists
- On Hardness and Liquidity
- On the Void, and How it Happens that Our Senses Are Not Aware of Certain Bodies
- On the Number of Elements and on Their Qualities
- Description of a New World, and on the Qualities of the Matter of Which it is Composed
- On the Laws of Nature of this New World
- On the Formation of the Sun and the Stars of the New World
- On the Origin and the Course of the Planets and Comets in General; and of Comets in Particular
- On the Planets in General, and in Particular on the Earth and Moon
- On Weight
- On the Ebb and Flow of the Sea
- On Light
- On the Properties of Light
- That the Face of the Heaven of That New World Must Appear to Its Inhabitants Completely like That of Our World