184 THE PRINCIPLES OF SCIENCE 



the idea of sameness in time and place. Always now we would con- 

 ceive nature as a contimium in which gradualism is the predominant 

 (though not invariable) order of things. That conception is brought 

 to bear, as earlier indicated, even in the elementary operation of fitting 

 to our experimental "points" lines along which we interpolate and 

 extrapolate. Active here at the very instant we make a first apprecia- 

 tion of our data, the same conception remains active also right through 

 to the highest levels of theoretical analysis. 



CONTINUITY AND EXPLANATION 



The connection of intelligibility and continuity, though asymmetric, 

 is reciprocal. We seek a species of knowledge that presupposes con- 

 tinuity, and with us the recognition of continuity passes as knowledge. 

 The abrupt outbreak of flames from a pile of oily rags constitutes for 

 us a problem. To it we find a satisfactory solution in the conception 

 ( and detection ) of a slow process of oxidation, autoaccelerative as it 

 produces a continuous gradual rise of temperature. That rise simply 

 culminates in the appearance of flames, and these signify only a more 

 rapid progress of an oxidative process we conceive different only in 

 degree and not in kind from that taking place earlier. Passing from the 

 trivial to the cosmic, observe that no small part of the appeal of a cos- 

 mogony of continuous creation derives from the analogous suppres- 

 sion of a unique ( and unfathomable ) "beginning." 



Forever seeking continuity where continuity is not apparent, we 

 show ourselves still responsive to what was, even in the infancy of 

 science, taken as of principle by Democritus : 



Nothing can be created out of nothing, nor can it [something, pre- 

 sumably] be destroyed and returned to nothing. 



If a something seems to disappear into nothing, understanding or 

 explanation requires the conception of a posterior something into 

 which it has been metamorphosed. If a something seems to appear out 

 of nothing, understanding or explanation requires the conception 

 (and, if possible, detection) of an anterior something responsible for 

 its production. The sudden appearance of a positron-electron pair per- 

 plexes us until we can responsibly hypothesize the antecedent pres- 

 ence of an unperceived gamma ray from which they have been pro- 

 duced. Likewise we refuse to suppose that light is generated only to 

 vanish at its source and subsequently to reappear at its destination. 



