CHAP. X.] ABERDEEN. 305 



believe too much to be easily brought into bondage to any 

 set of opinions. 



With respect to the " material sciences," they appear to 

 me to be the appointed road to all scientific truth, whether 

 metaphysical, mental, or social, The knowledge which exists 

 on these subjects derives a great part of its value from ideas 

 suggested by analogies from the material sciences, and the 

 remaining part, though valuable and important to mankind, is 

 not scientific but aphoristic. The chief philosophical value of 

 physics is that it gives the mind something distinct to lay 

 hold of, which, if you don't, Nature at once tells you you are 

 wrong. Now, every stage of this conquest of truth leaves a 

 more or less presentable trace on the memory, so that 

 materials are furnished here more than anywhere else for 

 the investigation of the great question, " How does Knowledge 

 come?" 



I have observed that the practical cultivators of science 

 (e.g., Sir J. Herschel, Faraday, Ampere, Oersted, Newton, 

 Young), although differing excessively in turn of mind, have 

 all a distinctness and a freedom from the tyranny of words 

 in dealing with questions of Order, Law, etc., which pure 

 speculators and literary men never attain. 



Now, I am going to put down something on my own 

 authority, which you must not take for more than it is worth. 

 There are certain men who write books, who assume that 

 whatever things are orderly, certain, and capable of being- 

 accurately predicted by men of experience, belong to one 

 category ; and whatever things are the result of conscious 

 action, whatever are capricious, contingent, and cannot be 

 foreseen, belong to another category. 



All the time I have lived and thought, I have seen more 

 and more reason to disagree with this opinion, and to hold 

 that all want of order, caprice, and unaccountableness results 

 from interference with liberty, which would, if unimpeded, 

 result in order, certainty, and trustworthiness (certainty of 

 success of predicting). Eemember I do not say that caprice 

 and disorder are not the result of free will (so called),, 

 only I say that there is a liberty which is not disorder ? 



