The Question a Historical One.

In fact, there is no belief which we entertain which has so complete a logical basis as that to which I have just referred. It underlies tacitly 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 inductive processes. We must recollect that any human belief, however broad its basis, however defensible it may seem, is, after all, only a probable belief, and that our broadest generalizations are simply the highest degrees of probability. Though we page 7 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 that there may have been a time when evidence did not follow a first order, when the relations of cause and effect were not fixed and definite, and when external agencies did not intervene in the general course of Nature. Cautious men will admit that such a change in the order of Nature may have been possible, just as every candid thinker will admit that there may be a world in which two and two do not make four, and in which two straight lines do not in close 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 a historical question, and it is one that must be dealt with in the same way as any historical 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 the question, and by what light of criticism that evidence is to be interpreted. So far as I know, there are only three views—three hypotheses—which ever have been entertained, or which well can be entertained, respecting the past history of Nature.