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182 Commentary consistent. The fundamental cosmic process is the chance conglomeration, in the infinite welter of randomly moving atoms, of masses of atoms of all sizes, which gradually form rotating swirls or eddies (D7; 71c, 74f, 77). (There is no indication that the atomists offered any explanation of why the primitive cosmic motion was rotary; perhaps they relied on observation of such phenomena as the formation of eddies in flowing water.) Within each eddy the atoms tended to move uniformly along the axis of rotation (i.e., to sink), but since the speed of this uniform motion was proportional to the size of the atom the larger atoms tended to congregate at the bottom and in the centre of the swirl, forcing the smaller atoms upwards and outwards to the periphery. The organization of the observable world manifests the resulting pattern, with the centre of the cosmic swirl occupied by the heavier elements of earth and water, which are composed of larger and therefore, as we may now say, heavier atoms, while the upper and peripheral areas are occupied by the lighter elements (composed of smaller and lighter atoms) of air and fire. The differentiations between the atoms of the various elemental masses are, however, relative only. All atoms have, within the cosmic swirl, a uniform centripetal tendency; the tendency of the smaller atoms to move upwards and outwards is explained, not by any inherent tendency in them, nor by centrifugal force, but purely as the effect of pressure from the faster-moving, larger atoms (61a-b). We thus have a neat reconciliation between the (bulk of the) Aristotelian evidence and that of ps-Plutarch and Stobaeus. As the latter report, in the precosmic situation the atoms are weightless, since they have no tendency to move in any direction rather than in any other. In the cosmic context, as Aristotle, Theophrastus, and Simplicius testify, all the atoms have weight, since all move towards the centre of the cosmic vortex (observed by us as motion towards the earth, i.e., motion downwards); and the larger they are the greater their weight, i.e., the greater the force required to resist their centripetal motion. The above is a summary of the orthodox view of the evidence regarding the weight of the atoms. This view has, however, been challenged by D. O'Brien in his exhaustive study (O'Brien 40). O'Brien accepts the orthodox accounts both of the weight of the atoms within the cosmos and of their movement in the precosmic situation. He rejects, however, the inference drawn above that in the latter situation the atoms are weightless, arguing that whereas in the cosmos weight is a tendency to downward motion, in the precosmic situation weight has no connection with downward motion, but is expressed in speed of motion and force of impact. Central to his argument is 60b, where Simplicius describes the atoms as moved by their weight through the void. It seems clear that this is indeed a description of the movement prior to the formation of aggregates, including cosmic

The Atomists -- Leucippus and Democritus  

MACEDONIA is GREECE and will always be GREECE- (if they are desperate to steal a name, Monkeydonkeys suits them just fine) ΦΕΚ,ΚΚΕ,ΚΝΕ,ΚΟΜΜ...

The Atomists -- Leucippus and Democritus  

MACEDONIA is GREECE and will always be GREECE- (if they are desperate to steal a name, Monkeydonkeys suits them just fine) ΦΕΚ,ΚΚΕ,ΚΝΕ,ΚΟΜΜ...

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