262 THE SCIENCE OF LOGIC 



may be put in this way : If we are to understand by cumulative 

 evidence, one form of which is circumstantial evidence, a more 

 or less considerable collection of reasons or motives, all of which 

 point towards the truth of the judgment, and each of which, taken 

 by itself, would only create a suspicion of that truth, can such a 

 cumulation of reasons ever produce certitude? It is a matter of 

 experience that they often do produce an assent which excludes 

 all prudent fear of error, and which falls, therefore, within the 

 definition of certitude. Such assents are commonly described as 

 morally certain. 1 They constitute the vast majority of the assents 

 upon which man s ordinary activity in life is based. Nor is 

 there any reason why we should deny to them the quality of 

 certitude. No doubt, the evidence for them is not of that cogent 

 character which excludes even the abstract possibility of error, as 

 it is in the case of metaphysical certitude. But it can exclude all 

 prudent fear of error : so that in the concrete circumstances it is 

 morally impossible that we should be deceived. And if we find 

 ourselves in this state of mind, after having exercised all due care 

 and caution in weighing and analysing the evidence, we have certitude. 

 It has to be remembered, however, that in applying the 

 &quot; moral laws&quot; or &quot;generalizations&quot; already mentioned such, for 

 instance, as that &quot; man is naturally truthful &quot; to individual cases, 

 our assent must be for the most part qualified by some measure 

 of reserve. It will be a &quot; practical &quot; certitude : an assent upon 

 which a prudent man would act But this means, after all, that 

 the assent is in practice equivalent to a certain assent, though it 

 is not really a certain assent. For, even in the concrete circum 

 stances we may be deceived. If, for instance, it is an assent on 

 the authority of a fellow-man, it may happen that, notwithstand 

 ing his well-known prudence and care in observing facts, he was 

 in some unaccountable way deceived just on this occasion. Or, 

 even though his veracity may be above suspicion, he may have 

 had some interest, unknown to us, in deceiving us just this once, 

 and may have succumbed to the temptation. &quot; The unexpected 

 happened &quot; ; and in our surprise we begin to see that our &quot; prac 

 tical &quot; certitude was not certitude at all. Similarly, a jury reaches 

 &quot; practical certitude,&quot; on strong circumstantial evidence, that the 

 prisoner in the dock committed the murder of which he stands 

 accused. On this practical certitude the prisoner is condemned 

 to death : and all who have carefully followed the evidence agree 

 1 Cf. CLARKE, Logic, pp. 426-428. 



