242 THOUGHTS ON BELIEF AND EVIDENCE. 



stance in certain given circumstances, a single good observation might 

 establish a law. Where it expresses relations of a class of objects, a 

 number of examples may be necessary, and certain precautions are 

 required, to avoid rash and misleading generalization ; but, when we 

 have once reached a law, we apply it with confidence to all cases 

 really coming within its terms, because we have established in our 

 minds a general expectation of the uniformity of natural laws, which 

 is really the same mental state as our expectation of effects from 

 causes, and is explained in the same manner. 



Belief in opinions philosophical, moral, religious, political, or rela- 

 ting to personal character, has the same nature as our belief in the 

 generalizations of physical science. The opinion is the verbal expres- 

 sion of a generalization of the mind. It implies that, on these sub- 

 jects, there are real uniform relations of things, which may be known, 

 and which we consider that we know ; but the fact that the opinions of 

 mankind on these subjects vary to such a degree, as they are known to 

 do, shews either that the inductive process is less carefully performed, 

 owing to the subjects of examination not being objects of sense, or that 

 passion and prejudice interfere much more with our conclusions than 

 they can well do in generalizations which relate to the laws of external 

 nature. These difficulties affect real enquirers, but the proportion 

 is very large indeed of those who, in such matters, only accept the 

 instructions of others, and whose opinions, early received from those 

 whom they deem sufficient authorities, and impressed by repetition 

 and the force of example, become so associated with all their trains 

 of thought as to be firmly fixed independently of evidence. Hence 

 the strongly marked differences which prevail on all these matters of 

 opinion, and the certainty that they can only be removed when those 

 who try to form an independent judgment carry on their inquiries by 

 the same methods as would be employed in physical science, and 

 when the proportion of those who have really examined and' endea- 

 avoured to appreciate evidence is far greater than it is at present. 



Every opinion tends to excite or restrain some action. If the 

 opinion be true — that is, if it be the expression of the real mode of 

 existence and relations of the objects or ideas to which it refers, and 

 the real regular consequents of certain known antecedents — it leads 

 us to act with due regard to these relations, and thus to guide our 

 conduct so as to attain to well-being, whilst a false opinion necessarily 

 tends to produce uneasy thoughts, unwise conclusions, or disappointing 



