IGNORABIMUS ET RESTRINGAMUR. 109 



attempt to test the interpreting power of the theory of 

 descent in physiology his own most special province 

 of inquiry ? Why does he not labour at that hitherto 

 quite unworked- out branch, physiogenesis, at the his- 

 tory of the evolution of functions, at the ontogenesis 

 and phylogenesis of vital processes ? The one idea 

 which has lately been often spoken of as an important 

 discovery of Du Bois-Eeymond's [the idea which had 

 already been anticipated by Leibnitz, that the " innate 

 ideas," intuitions a priori have originated by trans- 

 mission from primordial experience, i.e., empirical, d 

 posteriori convictions], was distinctly enunciated by me 

 long before Du Bois-Eeymond (as he omits to mention), 

 in 1 866, in my " General Morphology " (vol. ii. p. 446), 

 and in 1868 in the "History of Creation" (vol. i. p. 

 31, vol. ii. p. 344). If Du Bois-Eeymond had prac- 

 tically busied himself with these problems he would 

 certainly have thought a little about the development 

 of consciousness, and not have set down as an eternally 

 insoluble problem, " How is it possible that matter can 

 think ? " a form of words, be it observed, which has 

 about as much sense as " how matter runs," or " how 

 matter strikes the hours." Surely he would have 

 guarded himself in that case from uttering the pon- 

 derous " Ignorabimus." 



The question has been repeatedly asked why two 

 such prominent Berlin biologists as Virchow and Du 



