26 THE FOUNDATION'S OF ZOOLOGY 



ing devotee of plain common sense may look for as unexpected a 

 shock when the magnifier of severe logic reveals the germs, if not 

 the full-grown shapes, of lively metaphysical postulates rampant 

 amidst his most positive and matter of fact notions." ^ 



Kant has shown, as Berkeley showed before him, that, instead of 

 discovering truth, philosophy has only the modest merit of preventing 

 error, and if men never made mistakes, but always reasoned wisely 

 and acted rightly, we should little need to study the nature of know- 

 ledge ; but while few men think, all have opinions ; and there are 

 certain perennial errors, idols, as Bacon calls them, which find in the 

 mind of man a dwelling-place so congenial that the doctrine of idols 

 bears the same relation to the interpretation of nature as that of 

 sophisms does to common logic. 



As we are forced, by the imperfection of our nature, to study the 

 principles of knowledge in order to guard ourselves from error, it 

 makes little difference whether we call the principles of science 

 metaphysical or not. 



We speak of physical science, but it would surely be more repug- 

 nant to the usage of common speech to call the principles of science 

 physical than to call them metaphysical ; for, while the data of 

 science are things known to sense, we must ask, with Berkeley, 

 whether it is not certain that the principles of science are neither 

 objects of sense nor of the imagination ; whether they do not arise 

 in the mind itself ; whether the sensible world is anything more than 

 the stimulus which calls forth the innate or latent powers of the 

 mind. We assuredly have no sense-organ by which a principle may 

 be perceived, except so far as we have by nature an organ of com- 

 mon sense. If the principles of science are perceived at all, rather 

 than apprehended, they must be perceived by some inner sense, for 

 which we know no sense-organ. 



" As understanding perceiveth not, that is, doth not hear, or see, 

 or feel, so sense knoweth not ; and although the mind may use 

 both sense and fancy, as means whereby to arrive at knowledge, 

 yet sense or soul, so far forth as sensitive, knoweth nothing. For, 

 as it is rightly observed in the * Theaetetus ' of Plato, science con- 

 sisteth not in the passive perceptions, but in the reasoning about 

 them." 



1 Huxley, " Collected Essays," VI., pp. 288, 289. 



