[bowman] fundamental PROCESSES IN HISTORICAL SCIENCE 509 



evidence relating to any event becomes available, not in a mass and at 

 a single juncture, but in successive parts separated usually by con- 

 siderable, and often by great, intervals of time. Within each of these 

 intervals an historian must base his conclusions and formulate his 

 narrative on the evidence then available. For this reason in the 

 present test each case will be dealt with on the basis that the trust- 

 worthy evidence relating to it becomes available, not at a single point 

 of time, but in successive stages or parts separated by intervals. 

 At each of these successive stages a probable conclusion will be 

 formulated on the basis of the evidence then available. The degree 

 of probability of the conclusion so formulated will be accurately 

 determined or conservatively estimated. Its actual value will be 

 shown by the subsequent addition of evidence. 



Case I. 



Case I will first be stated analytically in order to illustrate the 

 principles and working of the test. The case so analysed will then 

 be put in narrative form as an example of the remaining cases, which 

 will be given, without introductory analysis, only in that form. 



a. Analytical Statement of Case I. 



(Evidence, Part 1): "On a summer day, a lady, clad for the 

 street, emerged from her home. Opposite her in the sky, otherwise 

 bright and clear, were clouds of very threatening aspect. As she 

 stepped from the veranda, she raised her head in the direction of the 

 clouds with a motion of surprise, and stopping short she turned and 

 re-entered the house." 



If the evidence ceases at this point, it will afford ground for a 

 probable conclusion that the lady returned to the house to avoid 

 the threatened rain. The degree of probability in favor of this con- 

 clusion will be fixed, according to the superior measure of probability 

 as defined in the Century Dictionary, by the ratio of the number of 

 occurrences of the event to the total number of occasions in the course 

 of experience; i.e., in the present instance, approximately by the 

 number of ladies who, within a given large extent of territory and 

 within a given lengthy period of time, emerge from their homes under 

 circumstances similar to those described and return to the house for 

 shelter, as against the total number of ladies who, within the same 

 territory and period of time, and under the same circumstances, return 

 to the house for any reason, whether for shelter or for any other pur- 

 pose, such as to get an umbrella or rain-coat. It is impracticable to 

 secure definite statistics on such a point, but in view of the unwilling- 



