§ 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 formulae 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. § 1. In our view of the underlying reality of the physical order, as explained in the last chapter, we have scarcely gone further, except in the explicitness of our phraseology, than we should be followed by many who profess a complete disbelief in metaphysical construction and an exclusive devotion to positive natural science. From the side of positive science we have often been reminded that no hard-and-fast line can logically be drawn between the organic and the inorganic, that we are not entitled to assume that the continuity of evolution ceases when we are no longer able to follow it with our microscopes, that we are, with the eye of scientific faith, to discern in the meanest particle of matter the “promise and potency” of all life, and so forth. All which statements seem to be confused ways of suggesting some such conception of the physical order as we have attempted to put into more precise and logical form. It is not until we come to deal with the problem indicated by the title of this chapter that our most serious difficulties begin. We have to face the objections which may be urged against our view of the physical order on the strength of the principle known in inductive Logic as the “Uniformity of Nature.”