August 17, 1905] 



NA TURE 



369 



that the let of man is easier than it was. Mankind, 

 indeed, may be justly proud that this improvement has 

 been due to the successive efforts of each generation to 

 add to the heritage of linowledge handed down to it by 

 its predecessors, whereby we have been born to the accu- 

 mulated endowment of centuries of genius and labour. 



I am told that in the United States the phrase " 1 want 

 to know " has lost the simple meaning implied by the 

 words, and has become a mere exclamation of surprise. 

 .Such a conventional expression could hardly have gained 

 currency e.\cept amongst a people who aspire to know- 

 ledge. The dominance of the European race in America, 

 Australasia, and South Africa has no doubt arisen from 

 many causes, but amongst these perhaps the chief one is 

 that not only do " we want to know," but also that we 

 are determined to find out. And now within the last 

 quarter of a century we have welcomed into the ranks 

 of those who " want to know " an oriental race, which 

 has already proved itself strong in the peaceful arts of 

 knowledge. 



I take it, then, that you have invited us because you 

 want to know what is worth knowing ; and we are here 

 because we want to know you, to learn what you have to 

 tell us, and to see that South Africa of which we have 

 heard so much. 



The hospitality which you are offering us is so lavish, and 

 the journeys which you have organised are so extensive, 

 that the cynical observer might be tempted to describe 

 our meeting as the largest picnic on record. Although 

 we intend to enjoy our picnic with all our hearts, yet I 

 should like to tell the cynic, if he is here, that perhaps 

 the most important object of these conferences is the 

 opportunity they afford for personal intercourse between 

 men of like minds who live at the remotest corners of 

 the earth. 



We shall pass through \our land with the speed and 

 the voracity of a flight of locusts ; but, unlike the locust, 

 we shall, I hope, leave behind us permanent fertilisation 

 in the form of stiinulated scientific and educational activity. 

 And this result will ensue whether or not we who have 

 come from Europe are able worthily to sustain the lofty 

 part of prophets of science. We shall try our best to 

 play to your satisfaction on the great stage upon which 

 you call on us to act, and if when we are gone you shall, 

 amongst yourselves, pronounce the performance a poor 

 one, yet the fact will remain, that this meeting has 

 embodied in a material form the desire that the progress 

 of this great continent shall not be merely material ; and 

 such an aspiration secures its own fulfilment. However 

 small may be the tangible results of our meeting, we shall 

 always be proud to have been associated with you in your 

 efforts for the advancement of science. 



We do not know whether the last hundred years will be 

 regarded for ever as the saeciilum mirabile of discovery, 

 or whether it is but the prelude to yet more marvellous 

 centuries. To us living men, who scarcely pass a year of 

 our lives without witnessing some new marvel of dis- 

 covery or invention, the rate at which the development 

 of knowledge proceeds is truly astonishing; but from a 

 wider point of view the scale of time is relatively un- 

 important, for the universe is leisurely in its procedure. 

 Whether the changes which we witness be fast or slow, 

 thev form a part of a long sequence of events which begin 

 in some past of immeasurable remoteness and tend to 

 some end which we cannot foresee. It must always be 

 profoundTy interesting to the mind of man to trace 

 successive cause and effect in the chain of events which 

 make up the history of the earth and all that lives on it, 

 and to speculate on the origin and future fate of animals, 

 and of planets, suns, and stars. I shall try. then, to set 

 forth in my address some of the attempts which have been 

 made to formulate evolutionary speculation. This choice 

 of a subject has, moreover, been almost forced on me by 

 the scope of my own scientific work, and it is, I think, 

 justified by the name which I bear. It will be my fault 

 and your misfortune if I fail to convey to you some part 

 of the interest which is naturally inherent in such re- 

 searches. 



The man who propounds a theory of evolution is 

 attempting to reconstruct the history of the past by means 

 of the circumstantial evidence afforded by the present. 



NO. 1868, VOL. 72] 



The historian of man, on the other hand, has the 

 advantage over the evolutionist in that he has the written 

 records of the past on which to rely. The discrimination 

 of the truth from amongst discordant records is frequently 

 a work demanding the highest qualities of judgment ; yet 

 when this end is attained it remains for the historian to 

 convert the arid skeleton of facts into a living whole by 

 clothing it with the flesh of human motives and impulses. 

 P'or this part of his task he needs much of that power of 

 entering into the spirit of other men's lives which goes, 

 to the making of a poet. Thus the historian .should 

 possess not onlv the patience of the man of science in the 

 analysis of fact's, but also the imagination of the poet to 

 grasp what the facts have meant. Such a combination is 

 rarely to. be found in equal perfection on both sides, and 

 it would not be hard to analyse the works of great 

 historians so as to see which quality was predominant in 

 each of them. . 



The evolutionist is spared the surpassmg difhculty ot 

 the human element, vet he also needs imagination, 

 although of a different vharacter from that of the historian. 

 In its lowest form his imagination is that of the detective 

 w^ho reconstructs the story of a crime; in its highest it 

 demands the power of breaking loose from all the trammels 

 of convention and education, and of imagining something- 

 which has never occurred to the mind of man before. 

 In every case the evolutionist must form a theory for the 

 facts before him, and the great theorist is only to be 

 distinguished from the fantastic fool by the sobriety of 

 his judgment — a distinction, however, sufficient to make 

 one rare and the other only too common. 



The test of a scientific theory lies in the number of facts 

 which it groups into a connected whole ; it ought besides 

 to be fruitful in pointing the way to the discovery and 

 coordination of new and previously unsuspected facts. 

 Thus a good theory is in effect a cyclopedia of know- 

 ledge, susceptible of' indefinite extension by the addition of 

 supplementary volumes. 



Hardly any theory is all true, ana many are not all 

 false. A theory may be essentially at fault and yet point 

 the way to triith, and so justify its temporary existence. 

 We should not, therefore, totally reject one cr other of 

 two rival theories on the ground that they seem, with our 

 present knowledge, .mutually inconsistent, for it is likely 

 that both mav contain important elements of truth. The 

 theories of which I shall have to speak hereafter may 

 often appear discordant with one another according to our 

 present lights. Yet we must not srruple to pursue the 

 several divergent lines of lli,.u:4lit f. their logical con- 

 clusions, relying on future discovery to eliminate the false 

 and to reco'ncile, together the truths which form part of 

 each of them. 



In the mouths of the unscientific evolution is often 

 spoken of as almost synonymous with the evolution of 

 the various species of animals on the earth, and this again 

 is sometimes thought to be practically the same thing as 

 the theory of natural selection. Of course those who are 

 conversant with the history of scientific ideas are aware 

 that a belief in the gradual and orderly transformation 

 of nature, both aniiiiate and inanimate, is of great 

 antiquity. 



We may liken the facts on which theories of evolution 

 are based to a confused heap of beads, from which a keen- 

 sighted searcher after truth picks out and strings together 

 a few which happen to catch his eye, as possessing certain 

 resemblances. Until recently, theories of evolution in both 

 realms of nature were partial and discontinuous, and the 

 chains of facts were correspondingly short and discon- 

 nected. At length the theory of natural selection, by 

 formulating ihe 'cause of the 'divergence of forms in the 

 organic world from the parental stock, furnished the 

 naturalist with a clue by which he examined the disordered 

 mass of facts before him, and he was thus enabled to go 

 far in deducing order where chaos had ruled before ; but 

 the problem of reducing the heap to perfect order will 

 probably baffle the ingenuity of the investigator for ever. 



■ So illuminating has been this new idea that, as the 

 whole of nature has gradually been re-examined by its aid. 

 thousands of new facts have been brought to light, and 

 have been strung in due order on the necklace of know- 

 ledge. Indeed, the transformation resulting from the new 



