352 THE GRAMMAR OF SCIENCE 



and wherever the physical conditions are suitable. The 

 hypothesis does not in the least explain the appearance of 

 life ; it merely formulates its appearance as a routine on 

 the occurrence of certain phenomena. Whenever a planet 

 passing through the azoic stage begins to consolidate 

 and cool, then begins the chemical evolution which ends 

 in the first stage of life ; but why this succession of 

 stages takes place is no more a subject of knowledge 

 than ivJiy the sun rises daily. As we describe the latter 

 so we could describe the former, were we capable of closely 

 watching for millions of years the physical history of a 

 planet. 



^ 10. — The Origin of Life in an ^'^ ultra-scientific''^ Cause 



As to the hypothesis of a " special creation," science 

 could not accept it as a contribution to knowledge had it 

 even been able to cross-examine the only witness to the 

 proceeding. The object of science is to classify and 

 resume in brief formulae the phases of our perceptual 

 experience. It has to knit together all our sense- 

 impressions by conceptual links, and thus to enable us to 

 take a wide survey of the universe with the least possible 

 expenditure of thought. Since time is a mode under 

 which we perceive things, we cannot accurately assert of 

 the earth that such and such changes occurred " between 

 one and two hundred million years ago." What we really 

 mean is this : that in order to resume and classify our 

 perceptual experience of the earth, we form a conceptual 

 model of it, and such a model we conceive to have passed 

 through certain changes one or two hundred million years 

 ago in absolute time (p. 189). Such a statement is 

 ultimately involved in the formulae by which we resume 

 our immediate sense-impressions, and its scientific validity 

 does not depend upon its describing something which 

 took place beyond the sphere of our perceptions, but upon 

 its flowing from laws which accurately describe the whole 

 of our present perceptual experience in the same field. 

 Now the hypothesis of a " special creation " cannot be 



