54 INDUCTION. 



more favourable reception from the scientific world 

 than his speculations on colours. It seems to be now 

 considered by natural philosophers as sufficiently 

 established, that plants and animals, in the process of 

 growing up from their germs, have a tendency to 

 develop themselves in a much more uniform manner 

 than they in fact do; that the differences, for example, 

 of leaf, flower, and fruit, are mere modifications of 

 one general phenomenon ; or (which is only another 

 expression for the same idea) joint results of one 

 common tendency and of several partial causes com- 

 bining with it. 



8. In the preceding discussion we have recog- 

 nised two kinds of empirical laws : those known to 

 be laws of causation, but presumed to be resolvable 

 into simpler laws ; and those not known to be laws of 

 causation at all. Both these kinds of laws agree in the 

 demand which they make for being explained by 

 deduction, and agree in being the appropriate means 

 of verifying such deduction, since they represent ths 

 experience with which the result of the deduction 

 must be compared. They agree, further, in this, that 

 until explained, and connected with the ultimate 

 laws from which they result, they have not attained 

 the highest degree of certainty of which laws are 

 susceptible. It has been shown on a former occasion 

 that laws of causation which are derivative, and com- 

 pounded of simpler laws, are not only, as the nature 

 of the case implies, less general, but even less certain, 

 than the simpler laws from which they result ; not so 

 positively to be relied upon as universally true. The 

 inferiority of evidence, however, which attaches to 

 this class of laws, is trifling compared with that 

 which is inherent in uniformities not known to be 



