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NATURE 



[ywie 21, 1883 



lowest animal they knew, a process which progressed step by 

 step by means of the gradual addition of small differences, until 

 the animal attained its perfect form. That was what was meant 

 by the process of evolution. At this point he thought it might 

 be desirable that he should deal with what he might speak of as 

 the a priori objections to the doctrines of evolution. He had 

 had opportunities of making extensive acquaintance with those 

 objections during the past twenty years or so. He divided them 

 into three categories: ( I) That evolution was impossible; (2) 

 that it was immoral ; and (3) tint it was oppo-ed to the argu- 

 ment of design. Now that was a very heavy indictment, but he 

 thought they must plead " not guilty " upon all three counts. It 

 required no great amount of reasoning to convince one that that 

 which happened could not be impossible ; that that which 

 happened thousands and millions of times every hour and every 

 minute in this world as it now was, under certain conditions, 

 could not be held without further evidence to be impossible 

 under somewhat different condition-. Secondly, with re- 

 gard to the question of morality. He had never under- 

 stood that argument, and hail always been disposed to 

 reply that the morality which opposed itself to truth committed 

 suicide. With regard to the argument of design he would not 

 discuss that point himself, but would beg them to listen for a 

 moment to words that would carry far more weight than any of 

 his own could carry on that topic : — " The philosopher beholds 

 with astonishment the production of things around him. Uncon- 

 scious particles of matter take Iheir stations and severally range 

 themselves in an order so as to become collectively plants 

 or animals, i.e. organised bodies with parts bearing strict and 

 evident relation to one another and to the utility of the whole ; 

 and it should seem that these particles could not move in any 

 other way than they do, for they testify not the smallest sign of 

 choice, or liberty, or discretion. There may be particular intelli- 

 gent beings guiding their motions in each case, or they may be 

 the results of trains of mechanical dispositions fixe 1 beforehand 

 by intelligence or appointment and kept in action by a power at 

 the centre." They might imagine, and not unreasonably, that 

 those were the words of some ultra-evolutionist of the present 

 day who desired to set himself right with the argument from 

 design ; but they were not so. They were more than eighty 

 years old, and they were contained in the 2yA chapter of a book 

 which was very much talked about, but, he was afraid, very little 

 read, namely, the "Natural Theology " of Archdeacon Paley. 

 When he was a boy that book was a ve y great favourite of 

 his, partly for its own merits, and partly because it was 

 one of the few books he was allowed to read on Sundays. 

 He found it much more entertai ing 'ban mo.t of the books in- 

 cluded in that category. But from what had been since said of 

 the Atheistic tendencies of the doctrine of evolution he began to 

 think that he stood before them a miserable example of the 

 manner in which a man's mind might be poisoned by early in- 

 struction, and that his incapacity to understand the force of the 

 arguments against evolution arose from the circum-tance that in 

 his early childhood he was indoctrinated with the reasonings of 

 a great divine of the Church. — Pro r essor Huxley now proceeded 

 to co isider the next point, the coming into existence of the 

 nautilus sp:cies in contradistinction from the origin of a 

 particular nautilus as an individual. lie showed that, accord- 

 ing to all the evidence tint could be gathered, there was 

 every reason to believe the forms of animal life five thousand 

 years ago were practically the same as they were now. If 

 there were no other means of knowing anything about the 

 history of animal life, undoubtedly this experience, resting 

 up an a duration of five thousand years, would have fur- 

 nished an apparently sufficient basis for a generalisation, 

 tending to the conclusion that the forms of animal life had 

 not changed during that period. Not only had that generalisation 

 been made, but it had been concluded that the forms of animal 

 life were unchangeable, a totally different proposition, the valid- 

 ity of which rested, among other things, on the proportion 

 between our actual experience, supposing it to extend over that 

 time.and our possibleexperienceof thedurationoflifeon the globe. 

 It would, he thought, be absolutely impossible for any of them, 

 however good their vision, to say from actual observation of the 

 hour hand of a watch for four seconds that it had moved during that 

 interval, and in point of fact the space over which it would move 

 was so minute as to be indiscernible, even through a magnifying 

 glass. Yet they knew very well that it had moved, and if they 

 watched it for four or five minutes, the evidence of its movement 

 would be perfectly obvious, even to the naked eye. They would 



observe, therefore, that a period of observation which extended 

 over the nine-hundredth part of an hour, would give them no 

 conception from which it would be possible to draw a 

 conclusion as to what had happened during the total period. 

 Now geologists told them that the whole depth and extent of the 

 fossiliferous rocks, which composed a considerable portion of the 

 earth's crust, represented a period of time at least one thousand 

 times as great as the historical period. That was a point upon 

 which tbere could be no room for hesitation. Hence it 

 followed that when they acquainted themselves with the suc- 

 cession of animal forms which were embedded at different depths 

 in the earth's crust, they did exactly what the observer of a watch 

 did when he kept his eyes fixed on it, not for four seconds but 

 for an hour, in which latter ca-e the movement was not only 

 conspicuous, but such as commonly served to indicate the lapse of 

 time. If that analogy held good, the slow procession of events 

 which might be absolutely indiscernible in the ourse of 5,°°° 

 years, would become obvious and plain when the period of ob- 

 servation was extended to a thousand times that period. And 

 that was exactly what happened, for if they went back in the 

 series of stratified rocks they found the genus nautilus, which in 

 the present day was represented by one or two species, repre- 

 sented in the long period of its history by many other 

 species. As far back as the Upper Silurian formation the 

 genus nautilus was represented by an abundant number of 

 shells fabricated by animals having all the essential peculiarities 

 which he had described. In the geological specimens before 

 him, and which were taken from the rich collection in the 

 Woodwardian Museum, there were forms of nautili which no 

 one doubted were to all intents and purposes the same in their 

 general structure as the pearly nautilus of the present day, 

 although they were at least 5,000,000 years old. Now came 

 the main question : were those nautili whose history extended 

 back through such a prodigious range of time identical in character 

 with the modern species ? So far as he knew there was nothing 

 in the nature of things to show why a succession of generations 

 which remained unchanged through 5,000 years should not re- 

 main so for 50,000 or 50,000,000 years. The facts, ho.v- 

 ever, showed that there had been rather more than 100 dis- 

 tinct species of nautilus, each having as good a title to be called 

 a species as Nautilus pompitius itself. No one of these species 

 had endured for more than a p artion of the duration of the whole 

 genus, and many species had existed contemporaneously, those 

 species, however, except perhaps two, were now extinct, so that 

 now they were brought face to face with the heart of the ques- 

 tion : by what hypothesis could they account for those pheno- 

 mena? They were driven into hypothesis of some kind or other, 

 because it was impossible to have any evidence of contemporary 

 witnesses of facts which went so far back into the past. So far 

 as he knew there were only two possible alternative hypotheses 

 by which they could pretend to account for those facts. One of 

 these hypotheses was what he ventured to call the hypothesis ol 

 construction. That hypothe-is was that every one of those species 

 was put together. It was making a needless difficulty to suppose 

 that each species came out of nothing, because they knew that 

 the body of the nautilus was made up of materials which were 

 familiar to them in an inorganic state on the earth's surface ; so 

 that by the hypothesis of construction some agency had put 

 together those materials a hundred times or so during the period 

 that had elapsed from the formation of the Silurian rocks to the 

 present day, as an artist constructed his « ork, or as a mechanician 

 put together the parts of his machine. That was one hypothesis. 

 For his part, he had not a word to say a priori against the pos- 

 sibility of that hypothesis. It was certainly conceivable and 

 therefore, according to Hume's maxim, it was possible. 

 But they must bring it, like all other hypotheses, to the test of 

 facts and inquire how far it stood that test. He thought the 

 hypothe is of construction presented two large and almost in- 

 superable difficulties. The one was that it was absolutely opposed 

 to everything tint they had received traditionally concerning the 

 origin of animal forms, and the second was that it was no less 

 opposed to every doctrine which might reasonably be held upon 

 grounds of sane science. It stood to rea on and common sense 

 that they could have recourse only to those causes for the 

 assumption of which there was same ground of analogy. The 

 business of science would be extre nely easy if for every event 

 one were permitted to invent special causes having no analogy in 

 nature. The difficulty of science was in tracing every event to 

 those causes which were in 1 resent operation. That difficulty 

 was being so constantly overcome that it had become a canon of 



