USE OF A SYMBOLICAL LANGUAGE. 247 



of acknowledged truth^ that x^ should denote the chance 

 of the truth of x on the assumption that a is true^ and 

 that therefore Xx mnst simply denote the chance that x is 

 true, with no assumption beyond the understood data of the 

 problem, it soon became evident that this notation would 

 express many of the laws of probability in neat and compact 

 formulae, and also that it would contribute towards pre- 

 cision of reasoning from its constant reference, by means 

 of its suffixes, to the assumptions on which any argument 

 in probability rested. It is well known that of all mathe- 

 matical subjects probability is the one in which mistakes 

 are most apt to be made ; and these mistakes are usually 

 the result of correct reasoning based upon unperceived 

 false assumptions. These assumptions, for the most part, 

 would be readily seen to be false, if they were only 

 expressed; a notation therefore that actually forces them 

 on the attention must be considered as possessing one very 

 important advantage in that fact alone. 



As this new scheme of probability-notation quite super- 

 seded that which formed the basis of the paper which had 

 been already submitted to the referees of the Mathema- 

 tical Society, these gentlemen naturally declined (on the 

 scheme being communicated to them through the Honorary 

 Secretary, Mr. Tucker) to pronounce any opinion either 

 upon the original paper or on the proposed alterations, till 

 the whole was recast and rewritten. When this was done, 

 and the paper again submitted to them, they advised its 

 publication. 



In my former paper in ' Mind,^ " On Symbolical Rea- 

 soning," I referred to the analogy between the relation 

 connecting antecedent and consequent in logic and that 

 connecting subject and predicate in grammar. Would it 

 be presumptuous to suggest as a probable hypothesis that 

 this analogy is more than a mere coincidence, and that it 



