THE FIRST AND THE LAST CATASTROPHE. 275 



process. Moreover, being exactly alike, they cannot have existed for- 

 ever, and thei-efore they must have been made. As Sir John Herschel 

 said, " they bear the stamp of the manufactured article." 



Now, into these further deductions I do not propose to enter at all. 

 I confine myself strictly to the first of the deductions which Prof 

 Clerk Maxwell made upon this theory. He said that because these 

 molecules are exactly alike, and because they have not been in the 

 least altered since the beginning of time, therefore they cannot have 

 been produced by any process of evolution. It is just that question 

 which I want to discuss. I want to consider whether the evidence 

 that we have to prove that these molecules are exactly alike is sufii- 

 cient to make it impossible that they can have been produced by any 

 process of evolution. The position, that this evidence is not sufiicient, 

 is evidently by far the easier to defend, because the negative is pro- 

 verbially hard to prove ; and, if any one should prove that a process 

 of evolution was impossible, it would be an entirely unique thing in 

 science and philosophy. In fact, we may see from this example pre- 

 cisely how great is the influence of authority in matters of science. 



If there is any name among contemporary natural philosophers to 

 whom is due the reverence of all true students of science, it is that 

 of Prof Clerk Maxwell. But if any one, not possessing his great 

 authority, had put forward an argument founded apparently upon a 

 scientific basis, in which there occurred assumptions about what things 

 can and what things cannot have existed from eternity, and about the 

 exact similarity of few or more things established by experiment, we 

 should say, " Past eternity ; absolute exactness ; " and we should pass 

 on to another book. The experience of all scientific culture, for all 

 ages during which it has been a light to men, has shown us that we 

 never do get at any conclusions of that sort. We do not get at con- 

 clusions about infinite time or infinite exactness. We get at conclu- 

 sions which are as nearly true as experiment can show, and some- 

 times which are a great deal more correct than direct experiment can 

 be, so that we are able actually to correct one experiment by deduc- 

 tions from another ; but we never get at conclusions wliich we have a 

 right to say are absolutely exact; so that, even if we find a man of the 

 highest powers saying that he had reason to believe a certain state- 

 ment to be exactly true, or that he believed a certain thing to have 

 existed from the beginning exactly as it is now, we must say, "It is 

 quite possible that a man of so great eminence may have found out 

 something which is entirely difierent from the whole of our previous 

 knowledge, and the thing must be inquired into. But, notwithstand- 

 ing that, it remains a fact that this piece of knowledge will be abso- 

 lutely of a difierent kind from any thing that we knew before." 



Now. let us examine the evidence by which we know that the 

 molecules of the same gas are as near as may be alike -in weight and 

 in rates of vibration. There Avere experiments made by Dr. Graham, 



