44 THE POPULAR SCIENCE MONTHLY. 



the facts upon which that conception is based, that chance should 

 have any place in the universe, or tbat events should follow anything 

 but the natural order of cause and effect. We have come to look upon 

 the present as the child of the past and as the parent of the future; 

 and, as we have excluded chance from any share or part in the order 

 of things, so in the present order of Nature men have come to neglect, 

 even as a possibility, the notion of any interference with that order. 

 And, whatever may be men's speculative notions upon those points, it 

 is quite certain that every intelligent person guides his life and risks 

 his fortune upon the belief that the order of Nature is constant, and 

 the relation of cause to effect unchanged. 



In fact, there is no belief which we entertain which has so com- 

 plete a logical basis as that to which I have just referred. It tacitly 

 underlies every process of reasoning ; it is the foundation of every 

 act of the will. It is based upon the broadest induction, and it is 

 verified by the most constant, regular, and universal of deductive 

 processes. But we must recollect that any human belief, however 

 broad its basis, however defensible it may seem, is, after all, only a 

 probable belief, and tbat our broadest generalizations are simply 

 statements of the highest degrees of probability. Though we are 

 quite clear about the constancy of Nature at the present time, and in 

 the present order of things, it by no means follows necessarily that 

 we are justified in expanding this generalization into the past, and in 

 denying absolutely tbat there may have been a time when Nature did 

 not follow a fixed order, when the relations of cause and effect were 

 not definite, and when external agencies did not intervene in the gen- 

 eral course of Nature. Cautious men will admit that such a change 

 in the order of Nature may have been possible, just as a very candid 

 thinker may admit that there may be a world in which two and two 

 do not make four, and in which two straight lines do not inclose a 

 space. In fact, this question with which I have to deal in the three 

 lectures I shall have the honor of delivering before you, this question 

 as to the past order of Nature, is essentially an historical question, and 

 it is one that must be dealt with in the same way as any other histori- 

 cal problem. 



I will, if you please, in the first place, state to you what are the 

 views which have been entertained respecting the order of Nature in 

 the past, and then I will consider what evidence is in our possession 

 bearing upon these views, and by what light of criticism that evidence 

 is to be interpreted. So far as I know, there are only three hypotheses 

 which ever have been entertained, or which well can be entertained, 

 respecting the past history of Nature. 



Upon the first of these the assumption is, that the order of Nature 

 which now obtains has always obtained ; in other words, that the 

 present course of Nature, the present order of things, has existed 

 from all eternity. The second hypothesis is, that the present state of 



