Lecture 6.1 PreSocratic Physics
Read Timaeus
28a-60 selection on web
Sources: Aristotle’s Physics and Metaphysics
Doxographical tradition: record
of the opinions of philosophers
The Study of Things among the Presocratics
hylozoism: matter with animate characteristics
causes are the same for animate and inanimate things
problem of change: search for stability and unity behind the surface
change
how is change possible?
Heraclitus (fl. 500)
flux: all things flow
Parmenides (b. c 515 BC)
what is, is; what is not, is not
nothing from nothing
change is not
Zeno: confirms Parmenides by showing the absurdities of the Many
uses infinitesimals: Achilles and the tortoise
presumably doesn't believe in the possibility of
infinitesimals
or even finite division
but accepts it as a premiss from
his opponents
as such may be a response to Pythagorean geometry
Pythagoreans ran into the problem
of the irrational
Eleatics say "don't even start
cutting lines"
Empedocles (from Acragas c495-435)
a less sophisticated form of Anaxagoras
owes to Parmenides: nothing from
nothing
the all is a sphere
at some point it is perfect
but against Parmenides: its
perfection is not self-evident, it is caused
but not
always: it changes and does not change
there are four Ones which constitute many things
cycles of the world
Anaxagoras c 500-428 (traditional dates):
to Parmenides: nothing from nothing
against Parmenides: innumerable worlds
-
things infinite in number and smallness (infinite
division)
there can not be the least of anything
you can't cause something to cease to exist because
you cut it
"The Greeks are wrong to accept coming to be and perishing, for no
thing comes to be, nor does it perish, but they are mixed together from
things that are and they are separated apart."
-everything is in everything: moria, spermata
homoiomeries: flesh, hair etc; or hot, cold etc.?
-nous is apart, pure, self-ruled, mixed with nothing: quite different
from the microcosm/macrocosm view of Heraclitus where we are like and
therefore can know the all
begins the revolution
on the vortex: "at first it began to rotate from a
small area, but it now rotates over a greater range and it will rotate
over a still greater one"
"the dense and the wet and the cold and the dark
came together here, where the earth is now, but the rare and the hot
and the dry went out into the far reaches of the aither.
distinguishes between the mover and the moved
"in the beginning, all things were together"
like Empedocles' reign of love
an indeterminate chaos prior to differentiation
In general: there is a beginning of the world: chaos
very many Parmenidean ones
in response to Zeno:
infinitesimal
division, useful for accounting for change
rather than a
obstacle to change
Democritus
Leucippus (Miletus)
b. c460 (Abdera)
-response to Parmenides:
the need for atoms (indivisibles):
if they are to be, there can not be not-being in them
-without void there is no motion and no plurality
the void is non-existent
-creates a balance between phenomena and Eleatic reason:
void is non-existent
being has no part of non-being
differences of atoms:
rhythm: shape (A N)
touching: arrangments (AN NA)
turning: position (N Z)
atoms infinite in number and kind
-hooks and concaves
innumerable worlds (so Anaxagoras)
-vortex, membranes in contact with the vortex
two kinds of knowing (the Confirmations: kratunteria): skepticism
-sense perception: bastard: opinion and convention: sweet, bitter, etc.
-reason: legitimate: truth and reality: atoms and void
perception occurs by touch; aporroia from objects
Ancient and Modern Atomism
atom joined with the notion of element
empirical considerations
in chemistry, Gassendi, Newton and especially Boyle thought that matter
was ultimately made of atoms
Boyle through his work on gases
Laws of Proportion
John Dalton worked out relative weights of elements
Dalton’s law of definite proportions