1. Some of my readers may be familiar with a very striking digression in Buffon's Natural History (_Natural Hist. of Man_, §VIII.), in which he supposes the first man in full possession of his faculties, but with all his experience to gain, and speculates on the gradual acquisition of his knowledge. Whatever may be thought of his particular conclusions the passage is very interesting and suggestive to any student of Psychology. 2. See also Dugald Stewart (Ed. by Hamilton; VII. pp. 115-119). 3. Required that is for purposes of logical inference within the limits of Probability; it is not intended to imply any doubts as to its actual universal prevalence, or its all-importance for scientific purposes. The subject is more fully discussed in a future chapter. 4. As particular propositions they are both of course identical in form. The fact that the 'some' in the former corresponds to a larger proportion than in the latter, is a distinction alien to pure Logic. 5. The reason is obvious. The healthiest English lives in Madeira (viz. the consumptive ones) have now ceased to be reckoned as English; whereas the worst consumptive lives there (viz. the English) are now increased in relative numbers. CHAPTER X. _CHANCE AS OPPOSED TO CAUSATION AND DESIGN._ 1. The remarks in the previous chapter will have served to clear the way for an enquiry which probably excites more popular interest than any other within the range of our subject, viz. the determination whether such and such events are to be attributed to Chance on the one hand, or to Causation or Design on the other. As the principal difficulty seems to arise from the ambiguity with which the problem is generally conceived and stated, owing to the extreme generality of the conceptions involved, it becomes necessary to distinguish clearly between the several distinct issues which are apt to be involved.