THE PRINCIPLES OF SCIENCE 171 



selves formless, inchoate, inapprehensible— that they can be "taken 

 in" only as the human mind imposes on them its own patterns of com- 

 prehension. To the contemplation of experience we thus bring our 

 own ways of seeing: e.g., we "see" an ordered world close bound in 

 chains of causal connection. Such ways of seeing or knowing are not 

 imposed upon us by our experience. On the contrary, they are pre- 

 suppositions of human experience. These patterns of thought consti- 

 tute the co-ordinate system in which we view and measure our ex- 

 perience, the ledger form in which we enter our findings as we "take 

 stock" of that experience. 



Kant felt that men must always view the world in terms of certain 

 unchanging forms innate to their very humanity: for him these forms 

 were a priori absolutely. Contrariwise, I will regard the regulative 

 principles of science as a priori only relatively. The efflorescence of 

 human minds in some particular age and clime, they remain forever 

 susceptible to change under the coercive pressure of an ever-widen- 

 ing human experience. To be sure, we are very slow to admit any 

 such coercion. The regulative principles are the most essential of the 

 heuristic tools we bring to bear on our experience. Perforce, we make 

 the tool harder than that on which it is to work. But it is not infinitely 

 harder: slowly the tool is itself reshaped by the uses to which it is put. 



The status of the regulative principles defies simple categorization. 

 Indubitable in the short term, none of them is today entertained in 

 quite the form it had some centuries ago, or will probably have some 

 centuries hence. Metaphysical in that they go far beyond all possi- 

 bility of empirical demonstration, yet are they diflFerent from the 

 perennially disputed abstractions of philosophy and theology: though 

 metaphysical, they elicit the general consensus of scientists who find 

 them justified by and in experience. Maintained with deep convic- 

 tion, they are appraised by pragmatic criteria which are, of their 

 very nature, provisional. Normally implicit, and never clearly for- 

 mulated as such, these principles may seem instinctive feelings (re- 

 flection of the scientific instinct of an age); but they are also judg- 

 ments (no less so because they may be unconscious judgments) in 

 that they change as new evidence comes within our experience. Cos- 

 mologic, as covert expressions of a conception of the world, their 

 primary function is methodologic, though they constitute no concrete 

 Method. Perhaps they are best described, as some of them were by 

 Newton, as "Rules of Reasoning in [Natural] Philosophy." They are 



