166 INDUCTION. 



universe as being on the whole carried on by general laws, and 

 not by special interpositions. To whoever holds this belief, 

 there is a general presumption against any supposition of divine 

 agency not operating through general laws, or in other words, 

 there is an antecedent improbability in every miracle, which, 

 in order to outweigh it, requires an extraordinary strength of 

 antecedent probability derived from the special circumstances 

 of the case. 



3. It appears from what has been said, that the asser 

 tion that a cause has been defeated of an effect which is con 

 nected with it by a completely ascertained law of causation, 

 is to be disbelieved or not, according to the probability or 

 improbability that there existed in the particular instance an 

 adequate counteracting cause. To form an estimate of this, 

 is not more difficult than of other probabilities. With re 

 gard to all known causes capable of counteracting the given 

 causes, we have generally some previous knowledge of the 

 frequency or rarity of their occurrence, from which we may 

 draw an inference as to the antecedent improbability of their 

 having been present in any particular case. And neither in 

 respect to known or unknown causes are we required to pro 

 nounce on the probability of their existing in nature, but only 

 of their having existed at the time and place at which the 

 transaction is alleged to have happened. We are seldom, 

 therefore, without the means (when the circumstances of the 

 case are at all known to us) of judging how far it is likely 

 that such a cause should have existed at that time and place 

 without manifesting its presence by some other marks, and (in 

 the case of an unknown cause) without having hitherto mani 

 fested its existence in any other instance. According as this 

 circumstance, or the falsity of the testimony, appears more 

 improbable, that is, conflicts with an approximate generaliza 

 tion of a higher order, we believe the testimony, or disbelieve 

 it ; with a stronger or a weaker degree of conviction, accord 

 ing to the preponderance : at least until we have sifted the 

 matter further. 



So much, then, for the case in which the alleged fact con- 



