A PRIMER ON ARISTOTLE'S PHYSICS AND COSMOLOGY

  • MOTION 
    • Forced motion ---force must be acting; when force stops, body stops. E.g. Cannonball; Fly Ball. 
    • Natural Motion---No force needed. Body "seeks" natural resting place. 
  • ORGANIZATION OF THE UNIVERSE 
    • Geocentric. Center of Earth is Center of Universe. 
    • Concentric Spheres starting with the Lunar Sphere, account for planetary motions. Stars on outermost sphere. 
  • MATERIAL STRUCTURE OF THE WORLD 
    • Divided into Sublunar Sphere and Superlunar Sphere (Heavens) 
    • In Sublunar Sphere:CHANGEABLE, TEMPORARY, MIXED, "CORRUPT" 
      • Fire -----Natural Motion is away from center of universe. 
      • Air -----Natural Motion is away from center of universe. 
      • Water -----Natural Motion is toward center of universe. 
      • Earth -----Natural Motion is toward center of universe 
    • In Heavens:CHANGELESS, ETERNAL, PURE, "PERFECT" 
      • Aether (Quintessence) -----Natural Motion around center of universe. 
  • Here is a depiction of the Aristotelian Universe from an 17th century print. Note the sublunar sphere with its depiction of the changeable weather, and the crystal spheres for each of the planets. 

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  • Here's a very brief biography of Aristotle 
  • On the Heavens by Aristotle is on-line here. 
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