Renes Descartes (1596-1650)
Cartesian Physics and Cosmology

Cartesian matter comes in three types:

There can exist no vacuum in between particles, i.e., the universe is completely filled with particles.

All this dust, these fine particles that fill the universe, rotate in whorls, or vortices.  These vortices push around the Sun and planets and moons and comets.

How does Descartes explain gravity?  The spinning earth creates a vortex into which heavy particles must and will fall due to the downward pressure created by the vortex.

How does Descartes explain magnetism?  Certain particles are screw shaped.  Other particles (magnets, iron) have screw shaped gaps in them that draw and hold the two particles together.  N and S polarity explained by right and left handed screws.

How do we explain life, animals? Animals are machines; life is mechanical, predetermined.  There is no "vital spirit" in the brains of animals, only particles passing from nerves and blood stream to/from brain.  All life on Earth is part of one big mechanical universe.

Only humans are different as we have souls.

Descartes has also removed FORCES from the discussion.  Forces were seen as part of the occult, mystical things operating at a distance.  In Cartesian physics, forces are gone as motion determines everything. There is no FINAL CAUSE as there was for Aristotle. Matter, people, simply do what they have to do.  There is no measurement of purpose or destination or goal or best use of my life.

Where does God fit in? God gave the world it's initial motion. The total amount of this motion in the universe is constant, unchanging.  God was the First Cause. That's it. After that, everything is determined by collisions. Essentially, this is a predetermined universe, a mechanical universe, a clockwork universe.  One might say that God created the universe and then went out for an eternal beer.

This motion concept is also remarkably modern, though in this case it would become "modern" by the mid-17th century, with Newton's concept of momentum.  In modern physics we speak of "conservation" laws, of things that cannot be destroyed or created. Motion, or momentum, is one of them.

God is banished from the natural world.  God's only role is to provide the First Cause.  But God remains omnipotent and everything still depends on God's will (in this case, to remain uninvolved).

God has been removed from matter yet is completely transcendent. Nature is silent about the nature of God. Nature is no longer full of messages from God. God does not interact in world to write messages.  Renaissance Naturalism, in which nature is full of symbols of divinity placed there for us to read, is gone.

The world is purely mechanistic, predetermined, mathematically tractable.  There is no Final Cause, no Aristotelian telos.

Gradually, followers of Descartes began to oust Aristotelians from the prestigious academic chairs in major universities so that by 1700, most major philosphers were Cartesians, not Aristotelians, except in the southern, more Catholic countries.

The Legacy of Descartes

In the post-Cartesian world of European natural philosophy, where are we?

Descartes has "proven" that

In the mechanical world of Descartes, there are/is How do we derive an Ethics from this?  

The Political Philosophy of Thomas Hobbes (1588-1679)

(inspired by Cartesian physics)



  so why form a government? why should individuals follow a social contract? in this world inspired by Cartesian physics,


Nicholas Malbranche (1638-1715)
Problems with occasionalism in a Cartesian universe: