Take the Lamarckian hypothesis,for example.Lamarck was a great naturalist,and to a certain extent went the right way to work;he argued from what was undoubtedly a true cause of some of the phenomena of organic nature.He said it is a matter of experience that an animal may be modified more or less in consequence of its desires and consequent actions.Thus,if a man exercise himself as a blacksmith,his arms will become strong and muscular;such organic modification is a result of this particular action and exercise.Lamarck thought that by a very simple supposition based on this truth he could explain the origin of the various animal species:he said,for example,that the short-legged birds which live on fish had been converted into the long-legged waders by desiring to get the fish without wetting their bodies,and so stretching their legs more and more through successive generations.If Lamarck could have shown experimentally,that even races of animals could be produced in this way,there might have been some ground for his speculations.But he could show nothing of the kind,and his hypothesis has pretty well dropped into oblivion,as it deserved to do.I said in an earlier lecture that there are hypotheses and hypotheses,and when people tell you that Mr.Darwin's strongly-based hypothesis is nothing but a mere modification of Lamarck's,you will know what to think of their capacity for forming a judgment on this subject.
But you must recollect that when I say I think it is either Mr.Darwin's hypothesis or nothing;that either we must take his view,or look upon the whole of organic nature as an enigma,the meaning of which is wholly hidden from us;you must understand that I mean that I accept it provisionally,in exactly the same way as I accept any other hypothesis.
Men of science do not pledge themselves to creeds;they are bound by articles of no sort;there is not a single belief that it is not a bounden duty with them to hold with a light hand and to part with it cheerfully,the moment it is really proved to be contrary to any fact,great or small.And if,in course of time I see good reasons for such a proceeding,I shall have no hesitation in coming before you,and pointing out any change in my opinion without finding the slightest occasion to blush for so doing.So I say that we accept this view as we accept any other,so long as it will help us,and we feel bound to retain it only so long as it will serve our great purpose--the improvement of Man's estate and the widening of his knowledge.The moment this,or any other conception,ceases to be useful for these purposes,away with it to the four winds;we care not what becomes of it!
But to say truth,although it has been my business to attend closely to the controversies roused by the publication of Mr.Darwin's book,Ithink that not one of the enormous mass of objections and obstacles which have been raised is of any very great value,except that sterility case which I brought before you just now.All the rest are misunderstandings of some sort,arising either from prejudice,or want of knowledge,or still more from want of patience and care in reading the work.
For you must recollect that it is not a book to be read with as much ease as its pleasant style may lead you to imagine.You spin through it as if it were a novel the first time you read it,and think you know all about it;the second time you read it you think you know rather less about it;and the third time,you are amazed to find how little you have really apprehended its vast scope and objects.I can positively say that I never take it up without finding in it some new view,or light,or suggestion that I have not noticed before.That is the best characteristic of a thorough and profound book;and I believe this feature of the 'Origin of Species'explains why so many persons have ventured to pass judgment and criticisms upon it which are by no means worth the paper they are written on.
Before concluding these lectures there is one point to which I must advert,--though,as Mr.Darwin has said nothing about man in his book,it concerns myself rather than him;--for I have strongly maintained on sundry occasions that if Mr.Darwin's views are sound,they apply as much to man as to the lower mammals,seeing that it is perfectly demonstrable that the structural differences which separate man from the apes are not greater than those which separate some apes from others.There cannot be the slightest doubt in the world that the argument which applies to the improvement of the horse from an earlier stock,or of ape from ape,applies to the improvement of man from some simpler and lower stock than man.There is not a single faculty--functional or structural,moral,intellectual,or instinctive,--there is no faculty whatever that is not capable of improvement;there is no faculty whatsoever which does not depend upon structure,and as structure tends to vary,it is capable of being improved.
