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THE POPULAR SCIENCE MONTHLY.— SUPPLEMENT. 



with American ; these, and some other doctrines 

 of geology, are involved in the argument. Now, 

 however certain they may be, the evidence upon 

 which they are established is circumstantial and 

 remote. It is easy enough to the geologist, who 

 is accustomed to it, but it does require special 

 study to master it fully. And there is no trace 

 whatever of these difficulties in the statement, 

 " Here's his hock." Convincing as that state- 

 ment is, it docs not carry along with the convic- 

 tion a fair estimate of the evidence on which it is 

 based. 



With this consideration in mind, let us com- 

 pare again the evidence for the descent of man 

 with that for the descent of the horse. The gen- 

 eration of men of any given race now existing is 

 descended from parents who, on the average, 

 differed imperceptibly from themselves. This has 

 not gone on forever, because physical evidence 

 proves a beginning to the present state of the 

 earth. Were the first men also the offspring of 

 parents "who differed imperceptibly from them- 

 selves, yet so that- the imperceptible difference 

 came just where we draw the line between man 

 and not-man ? Such a line would of course be 

 arbitrary, but we may suppose a certain hundred 

 generations, the change in each being impercepti- 

 ble, but still such that we should call the first 

 not-men and the last men. This is the supposi- 

 tion of a non-human ancestor, as made by the 

 evolutionist. If this supposition is rejected, the 

 first men may have originated (1) from parents 

 differing largely from them in structure ; (2) from 

 non-living matter, or (3) from non-existence, be- 

 ing men from the moment they began to be. We 

 are not bound to make any supposition at all 

 about the origin of the first men ; but, if we do 

 make any supposition, it must be oue of these. 



Suppose, however, that we want not merely to 

 make a supposition, but to infer from the facts 

 before us what actually happened. Then we 

 must make the assumption that there is some 

 sort of uniformity in Nature. Without this we 

 cannot infer at all, for inference consists in trans- 

 ferring the experience which we have had under 

 certain conditions to events happening under like 

 conditions, of which we have not had experience. 

 It is true that we cannot be absolutely sure of the 

 uniformity of Nature, or that our present concep- 

 tion of it is right ; but still it is the only thing 

 we have to go upon. Human knowledge is never 

 absolutely and theoretically certain, but a great 

 deal of it is practically certain, which is all we 

 want. 



Now, the production of man from non-living 



matter, or the coming of any kind of matter into 

 existence out of nothing, are things so entirely 

 without parallel in our existing experience, that 

 we cannot infer them unless our experience en- 

 tirely changes its character. If clay or mould 

 would form itself into a human body a few times, 

 we might learn something about the conditions 

 under which such a transformation takes place, 

 which would enable us to infer that it had taken 

 place before. If matter would occasionally come 

 into existence out of nothing, we might say what 

 kind of matter was most likely to do such a 

 thing, whether buttons or sovereigns were most 

 gifted with this faculty, and so on. But, even so, 

 some time must elapse before we could infer, be- 

 cause our whole conception of the order of things 

 would be turned topsy-turvy. 



If, therefore, we are to infer anything at all 

 about the origin of the first men, we must infer 

 that they descended from non-human ancestors. 

 What sort of ancestors these were is, in the pres- 

 ent state of knowledge, matter of conjecture 

 merely. To guide this conjecture, we have " the 

 homological structure, embryological develop- 

 ment, and rudimentary organs " of- existing men. 

 The evidence of this kind set forth by Darwin 

 seems to point with very great probability to an 

 ancestor more ape-like than man. Still these in- 

 dications are not so clear and unmistakable that 

 a less ape-like ancestor, as Vogt supposes, would 

 be inconsistent with the uniformity of Nature. 

 We are dealing with a long series of similar 

 events, the descent of each successive generation 

 from one very like it ; and though each event is 

 an example of what occurs habitually in our ex- 

 perience, yet the effect of the whole series of such 

 events is something of which we can only get 

 knowledge by means of paleontological evidence. 

 We can only, therefore, infer with a very moder- 

 ate amount of probability that men are descended 

 from this sort of animal or that sort of animal. 

 This is the point which will be set at rest by the 

 missing link. But I venture to think that the 

 evidence for the descent of man from some non- 

 human ancestor will be but very slightly strength- 

 ened by that discovery, and that it is now not 

 perceptibly less cogent than that for the descent 

 of the horse. 



For observe, that each alike depends on the 

 assumption of the uniformity of Nature. That 

 being given, the descent of man follows from the 

 originally fluid condition of the earth, proved by 

 physical observation and reasoning. Failing that, 

 the evidence for the descent of the horse vanishes 

 into thin air. It is not the least bit more likelv 



