742 SCIENTIFIC THOUGHT. 



tion which science is obliged to make being the inevitable 



one that Nature is intelligible to the human mind, which 



1. is the same as saying that we must assume the existence 



Order and "^ ° 



Unity. of some kind of Order. 



There exists, indeed, in the human mind a further 

 demand, which may l^e defined by saying that the con- 

 ception of order in Nature or of its intelligibility should 

 not be held merely as a formal iteration, but should be 

 expressed as a highest Unity by some term which conveys 

 to our minds something more than the idea of an empty 

 form. From this demand there have further arisen at 

 all times various attempts to give expression to the 

 ideas of unity, of simplicity, and of the significance of 

 the whole scheme of existence which we call Nature. 

 Such attempts do not form part of purely scientific 

 thought. They are speculations for which those prin- 

 ciples of science that are capable of exact enunciation 

 do not suffice. They have, indeed, frequently appeared in 

 the literature of the nineteenth century. But although 

 there are isolated cases where scientific authorities of the 

 first order have indulged in them, such authorities have, 

 as a rule, shown an increasing reluctance to deal with 

 fundamental questions or with principles which extend 

 beyond the limits of scientific thought. We have no 

 examples in the nineteenth century of such intellects as 

 those of Leibniz or Newton. However different these 

 two great thinkers of an earlier age may have been, they 

 had this in common, that for them the scientific and the 

 religious aspects were not only equally important, but 

 equally occupied their attention. The characteristic 

 difference was that Leibniz apparently strove after a 



