<P> Plato (c. 427--c. 347 BCE), if he had been familiar with the atomism of Democritus, would have objected to its mechanistic materialism . He argued that atoms just crashing into other atoms could never produce the beauty and form of the world . In Plato's Timaeus, (28B--29A) the character of Timeaus insisted that the cosmos was not eternal but was created, although its creator framed it after an eternal, unchanging model . </P> <P> One part of that creation were the four simple bodies of fire, air, water, and earth . But Plato did not consider these corpuscles to be the most basic level of reality, for in his view they were made up of an unchanging level of reality, which was mathematical . These simple bodies were geometric solids, the faces of which were, in turn, made up of triangles . The square faces of the cube were each made up of four isosceles right - angled triangles and the triangular faces of the tetrahedron, octahedron, and icosahedron were each made up of six right - angled triangles . </P> <P> He postulated the geometric structure of the simple bodies of the four elements as summarized in the adjacent table . The cube, with its flat base and stability, was assigned to earth; the tetrahedron was assigned to fire because its penetrating points and sharp edges made it mobile . The points and edges of the octahedron and icosahedron were blunter and so these less mobile bodies were assigned to air and water . Since the simple bodies could be decomposed into triangles, and the triangles reassembled into atoms of different elements, Plato's model offered a plausible account of changes among the primary substances . </P> <P> Sometime before 330 BCE Aristotle asserted that the elements of fire, air, earth, and water were not made of atoms, but were continuous . Aristotle considered the existence of a void, which was required by atomic theories, to violate physical principles . Change took place not by the rearrangement of atoms to make new structures, but by transformation of matter from what it was in potential to a new actuality . A piece of wet clay, when acted upon by a potter, takes on its potential to be an actual drinking mug . Aristotle has often been criticized for rejecting atomism, but in ancient Greece the atomic theories of Democritus remained "pure speculations, incapable of being put to any experimental test . Granted that atomism was, in the long run, to prove far more fruitful than any qualitative theory of matter, in the short run the theory that Aristotle proposed must have seemed in some respects more promising". </P>

Who said all matter is composed of tiny indivisible particles