The questions about the origin and forms of matter - about order and non-order - appear in all these explanatory systems. The notions of form and substance seem to be inherent in human thought; although nobody has ever seen formless matter, form and substance is nevertheless the everywhere appearing pair of fundamental building blocks.
Physics can be conceived as yet another project in the striving to unveil "eternal" structures. It is based on a conviction that there is a more essential level underneath the fugitive reality that we perceive with our imperfect senses; and it is accessible to man in the sense that he can create tales that reflect this more fundamental level.
Such a tale is a physical model. All physical statements, all physical conclusions, refer to models. A scientific theory differs from other tales by its claim to reflect what is out there, beyond laguage. All descriptions of course take place within language, but physical descriptions claim to have an objective core. In order to be ranked as physical, a theory must have well defined observational consequences, a physical model always has a greater range than the experiments upon which it resides, in that it supplies predictions about yet more phenomena, which can hopefully be experimentally verified. (Theory and model are terms that are used somewhat inconsistently, a theory is supposedly more all-embracing and well-established than a model. The current theory for particle interactions, which is experimentally very well established, is however called the Standard Model).
Already the pre-socratians asked for the elementary parts whereof the world consists, and introduced a set of notions that are still in use. In the physical nomenclature, we find concepts like "matter" and "forces", described by means of "inner" and "outer" qualities, where the latter, "outer" qualities, are those related to space and time, and the "inner" are those inherent in the described system.
According to the picture presented by today's physics, the world
is a highly stuctured system, with allows itself to be described
in very precise, mathematical terms.
Both matter and forces are represented in terms of elementary parts.
Matter
is described as consisting of elementary particles (smallest parts of matter,
which lack inner structure),
and all changes in the world are
brought back upon four elementary forces. In the conviction of the existence
of a deeper physical unity, there are furthermore aspirations to unify
these forces, which to a certain extent has been accomplished.
The agreements between theory and empirical data are taken as indications that
these tales about the world indeed reflect something like the real
structure of the world.
The Standard Model is consistent with all present experimental data.
The trust in empirical data is however of quite recent date,
the dominating conviction for most of historical time has been
that real knowledge is out of empirical reach.
The French enlightenment objection to Newton
was that his laws were too empirical: they do not answer why, they only state
what and how. The absolute knowledge must also contain an answer to the great
why, they claimed, it must give an answer to what the world really is.