THE BIOLOGY OF DAILY LIFE. 63 



include all the laws to which observation and 

 induction lead. A theory which did this 

 would, no doubt, go a great way to establish 

 any hypothesis of mechanism or of structure, 

 which might form an essential part of it ; but 

 this is very far from being the case except in a 

 few limited instances ; and till it is so, to lay 

 any great stress on hypotheses of the kind, 

 except in so much as they serve as a scaffold 

 for the erection of general laws, is to " quite 

 mistake the scaffold for the pile." Regarded in 

 this light hypotheses have often an eminent 

 use ; and a facility in framing them, if attended 

 with an equal facility in laying them aside 

 when they have served their turn, is one of the 

 most valuable qualities a philosopher can 

 possess ; while, on the other hand, a bigoted 

 adherence to them, or indeed to peculiar views 

 of any kind, in opposition to the tenor of facts 

 as they arise, is the bane of philosophy." 

 (Herschel, Nat. Phil, p. 204.) 



