Chapter III: The Meaning of Law

§ 1. The popular conception of the physical order as
exhibiting a rigid mechanical conformity to general
_laws_, conflicts with our metaphysical interpretation.
§ 2. Our interpretation would, however, admit of the
establishment of averages or approximately realised
uniformities by the statistical method, which deals with
occurrence _en bloc_ to the neglect of their individual
detail. § 3. “Uniformity” in nature is neither an axiom
nor an empirically verifiable fact, but a postulate. A
consideration of the methods actually employed for the
establishment of such uniformities or “laws” of nature
shows that we have no guarantee that actual concrete
cases exhibit _exact_ conformity to law. § 4. Uniformity
is a _postulate_ arising from our need of practical
rules for the control of nature. It need not for this
purpose be exact, and in point of fact our scientific
formulæ are only exact so long as they remain abstract
and hypothetical. They do not enable us to determine the
actual course of an individual process with certainty. §
5. The concept of the physical order as _mechanical_ is
the abstract expression of the postulate, and is
therefore essential to the empirical sciences which deal
with the physical order. § 6. Consideration of the
character of genuine machines suggests that the
mechanical only exists as a subordinate aspect of
processes which, in their full nature, are intelligent
and purposive 216