Physical Reality, Corpuscular Models, Continuum Models

Abstract

One view of physical reality is that the matter commonly perceived as filling space in fact consists principally of empty space, with an occasional bit of matter. Such a bit may be called an elementary particle. The distance between the bits of matter and the structure in which they are arranged, as well as their particular arrangement, dictates whether the gross material is perceived as a solid, as a liquid, or as a gas. A bit of matter may itself have a very rich structure, in which case the bit is no longer an elementary particle, but rather is in itself composed of elementary particles. This kind of structure is worthy of study. The scale of such structures is such that they are not accessible for purposes of describing the behavior of materials normally encountered in everyday experience. Neither is such structure interesting for most such purposes. The exceptions are, for example, that a solid is perceived as amorphous or as having a particular crystalline structure based on the symmetry of the arrangement of the matter in it. This affects its gross symmetry, that is, the mechanics of the macroscopic body reflects the arrangement of the bits of matter. The difficulty of scaling such theories up to the size of a body that interests us here makes it desirable to search for an alternative to description at this level of detail. Moreover, theories of such small structures are often revised, because they are not yet completely understood, and both deeper theoretical understanding and more sophisticated experimental work continue to appear. On the other hand, our experience of the gross behavior of the materials of everyday life, such as steel or water, is quite constant. Thus it is extremely rare for us to revise its mathematical description. The result is, for the purposes of modeling phenomena on the scales ordinarily perceived, it is appropriate to devise models that are independent of modern theories of atomic and subatomic physics. Two types of such models are corpuscular models and continuum models.