Physics VIII


a. dialectical, philosophical
            not demonstration
few specific observations
cf. confusion in Physics i.1

b. conclusions guide arguments
            primacy of circular locomotion   
            nature of heavy and light are assumed

c. Platonic inheritance: divided line

            eikasia                  pistis                                    dianoia                                    noesis
            conjecture            belief                                    understanding                        reason

Arist:  art                        sublunary nature            celestial spheres             unmoved mover

d. Unmoved Mover: an Exercise in Natural Theology
            from physics
            from metaphysics
            from psychology?

motion in general did not begin and will not end
-whatever is moved is moved by something else (nothing just starts)
            forced motion           
            natural motion: animals, simple bodies
-moved, moved mover, unmoved mover (accidentally moved)
-cannot have an infinite series of movers
            must be one thing at the beginning of the series
            is continuous; should be single not plural
-it maintains the first motion: circular locomotion
-it cannot be a finite or infinite magnitude; must be without magnitude at circumference


A. Does motion just spring into existence?
            [canvass the endoxa]
motion cannot simply come into being from absolute rest
time cannot exist in absolute rest, so there is no time before motion
                        so time cannot cease

B. Will motion stop?
no, what is potentially something else does not cease that potentiality

objections and responses to the position that change always is:
            a. no change is eternal
                        yes, but these changes are between contraries
                        and not all changes are between contraries
            b. inanimate change starts at some point
                        yes, but they must be started
            c. animals can start themselves (in them there is a beginning of motion)
                        yes, but even in still animals there is some motion
                                    or motion in the environment that stimulates them

some things are always in motion, others always at rest, others sometimes in motion and sometimes at rest
            a. Parmenides: all at rest: destroys physics
            b. Heraclitus: all in motion: destroys physics; makes nonsense of contrary change
            c. Some things at rest, others in motion: but the senses say otherwise

whatever is moved is moved by something else, for
            all movement is natural or unnatural
            all unnatural movement is caused from outside
            all natural movement is (ultimately) caused by an outside movement

A. there cannot be an infinite series of movements
            there must be a first mover
therefore, the first mover must be moved by itself

B. Where something moves itself there is a part that moves and a part that is moved
            and the moving part is moved incidentally

the unmoved first mover is eternal and one
            the unmoved first mover is not moved even incidentally
                        since thus it could not cause a continuous motion
            the primum mobile is eternal

locomotion is prior to other forms of change
            only locomotion is continuous

circular locomotion is continuous and  infinite
circular locomotion is the primary kind of locomotion
            simpler than linear locomotion           

the unmoved mover is without magnitude and on the circumference of the universe
            the unmoved mover cannot be either infinite or finite in magnitude
                         if finite, it could not be active for an infinite time