OPINION AND PROBABILITY 269 



and no certitude, as to how, when, where, or in what circumstances, 

 they will recur in the future, or have occurred in the past So 

 far as we know, they occur &quot;irregularly&quot;: they just &quot;happen&quot; 

 or &quot;chance &quot; to occur. Hence we speak of the &quot;chances&quot; for or 

 against the occurrence of some such event at a given time and 

 place, or in a given set of circumstances ; and we endeavour to 

 calculate those &quot;chances,&quot; for and against its happening, and so 

 to &quot;estimate its probability &quot;. Special treatises have been written 

 on the nature and rules of this logical calculus of probability or 

 chance l ; but in a general treatise on logic a brief statement of 

 the leading principles and their applications will be sufficient. 

 The first important concept that calls for examination in this 

 connexion is the concept of chance. 



Chance is not the negation of causality : nothing is casual in 

 the sense of being causeless. Every event, everything that happens 

 or begins to be, has a cause. There is a causal connexion be 

 tween any two events either of which has any positive influence 

 on the production or happening of the other. Induction aims at 

 discovering causal connexions. But there are phenomena, con 

 nected in time and space, which have no such obvious causal 

 influence on one another. Their concurrence in time or space is 

 a &quot;coincidence,&quot; a &quot;chance&quot; concurrence. In seeking for the 

 causes of a given phenomenon we meet several of its concomitant 

 circumstances, and recognize these to be &quot; irrelevant &quot;. Their 

 presence or absence has no influence on the phenomenon ; the con 

 nexion between them and it is not causal but casual a &quot; chance &quot; 

 connexion. 2 



For example, a person speaks of having &quot; chanced &quot; or 

 &quot; happened &quot; to meet a particular old friend from the country, 

 at a certain street corner in town, at a particular moment when 

 he was just in the act of posting a letter to that friend. It was 

 a &quot; remarkable coincidence,&quot; and &quot; unexpected occurrence &quot;. 

 Each part of the total phenomenon had its causes, but neither had 

 any influence in bringing about the other, nor can we see in the 

 causes of either part anything that would of its nature have any 

 influence in determining the coincidence, in time or space, of the 

 other part. Thus, the coincidence of phenomena not connected 

 as cause and effect, or of various &quot; indifferent &quot; or &quot; irrelevant &quot; 



1 C/. VENN, Logic of Chance ; BOUDON, Le calcul des probability ; BERTRAND, 

 Calcul des probabilites ; MANSION, Sur la portee objective du calcul des probabilites. 

 9 C/. VENN, Logic of Chance, p. 245. 



