MO THE SCIENCE OF LOGIC 



scientist, and of Professor Tyndall, in establishing the hypothesis of biogenesis, 

 and disproving that of abiogenesis or spontaneous generation. Yet, there are 

 scientists who still refuse to admit that the experiments of those two men finally 

 established the former, or disproved the latter hypothesis : a good illustration 

 of the possible differences of opinion as to the amount of verification that is 

 to be deemed adequate in any given case. &quot; Every effort,&quot; writes Professor 

 Windle, 1 &quot; to prove the existence of spontaneous generation, has so far failed. 

 It is true, all this amounts to is that no experiment has ever yet succeeded in 

 showing that spontaneous generation takes place, and there are those who 

 urge that some experiment may yet turn out to be successful.&quot; The experi 

 ments of Professor Burke of Cambridge, upon gelatine acted on by radium, 

 do not seem to lend any probability to the hypothesis of spontaneous genera 

 tion. Weismann unscientifically regards the latter as the only possible hypo 

 thesis, though holding at the same time that the process will for ever escape 

 observation. 



Finally, a brief comparison of the Atomic Theory (in chemistry) with the 

 Mechanical Conception of the Universe (in philosophy) will furnish an instructive 

 contrast between a strict scientific hypothesis and an unverifiable systematic 

 conception. The &quot; atomic theory &quot; in chemistry is an hypothesis which supposes 

 chemically simple bodies to be aggregates of particles indivisible by any known 

 chemical methods, and accordingly called atoms. This hypothesis is exceedingly 

 probable, if it is not indeed fully verified by the various arguments on which it 

 is based. One of these, for example, is drawn from the experimentally estab 

 lished Law of Multiple Proportions. For instance : nitrogen combines in 

 constant ratios by weight 28 parts with varying weights of oxygen, but 

 only on condition that these latter be always some multiple of a minimum 

 combining weight of oxygen 16 parts. Thus N 2 , 28 parts by weight of 

 nitrogen, combines respectively with 16, 32, 48, 64, 80 parts by weight of 

 oxygen, to form five different oxides ; N 2 O, N. 2 O 2 , N^Oj, N a O 4 , N 2 O S . 

 Now, does not this remarkable fact or law suggest, as a possible if not its only 

 possible explanation, that the mass of oxygen represented by 16 is a fixed, 

 constant, chemically indivisible portion of matter, an atom ? - Suppose 28 

 grammes of nitrogen and (say) 20 grammes of oxygen together submitted to the 

 chemical agencies capable of effecting a combination : why, if the mass of 

 oxygen were capable of indefinite division by those agencies, should 4 grammes 

 of oxygen invariably remain over ? Why should not that mass of 4 grammes 

 divide itself around on the 28 of nitrogen, seeing that these have an equally 

 strong affinity for all parts of the mass of oxygen ? But if we conceive the 

 28 grammes of nitrogen as containing a certain number of atoms twice as 

 many as 16 grammes of oxygen contain each pair of which nitrogen-atoms 

 unites, under the play of the chemical forces at work, with one atom of oxygen, 

 there will be evidently 4 grammes of atoms of oxygen left, each of which would 

 have to divide into four parts in order to give an additional share to each pair 

 of nitrogen-atoms. But the atom being, ex hypothesi, indivisible by the 

 chemical agencies at work, the 4 grammes of oxygen must remain unincorpor 

 ated into the compound. 



Many scientists regard this hypothesis that the chemically simple bodies 

 are made up of chemically indivisible particles, or atoms as an established 



1 Dublin Review, April, 1906, p. 340. * Nys, Cosmologie, p. 411. 



