SCIENTIFIC USE OF THE IMAGINATION 



73 



sinning against observed fact or demon- 

 strated law for a mind like that of 

 Darwin can never sin wittingly against 

 either fact or law we ought, I think, to 

 be cautious in limiting his intellectual 

 horizon. If there be the least doubt in 

 the matter, it ought to be given in favour 

 of the freedom of such a mind. To it a 

 vast possibility is in itself a dynamic 

 power, though the possibility may never 

 be drawn upon. It gives me pleasure to 

 think that the facts and reasonings of 

 this discourse tend rather towards the 

 justification of Mr. Darwin than towards 

 his condemnation ; for they seem to show 

 the perfect competence of matter and 

 force, as regards divisibility and distribu- 

 tion, to bear the heaviest strain that he 

 has hitherto imposed upon them. 



In the case of Mr. Darwin, observa- 

 tion, imagination, and reason combined 

 have run back with wonderful sagacity 

 and success over a certain length of the 

 line of biological succession. Guided by 

 analogy, in his Origin of Species he placed 

 at the root of life a primordial germ, from 

 which he conceived the amazing variety 

 of the organisms now upon the earth's 

 surface might be deduced. If this hypo- 

 thesis were even true, it would not be 

 final. The human mind would infallibly 

 look behind the germ, and, however 

 hopeless the attempt, would inquire into 

 the history of its genesis. In this dim 

 twilight of conjecture the searcher wel- 

 comes every gleam, and seeks to augment 

 his light by indirect incidences. He 

 studies the methods of nature in the 

 ages and the worlds within his reach, in 

 order to shape the course of speculation 

 in antecedent ages and worlds. And 

 though the certainty possessed by experi- 

 mental inquiry is here shut out, we are 

 not left entirely without guidance. From 

 the examination of the solar system, Kant 

 and Laplace came to the conclusion that 

 its various bodies once -formed parts of 

 the same undislocated mass; that matter 

 in a nebulous form preceded matter in 

 its present form ; that, as the ages rolled 

 away, heat was wasted, condensation 

 followed, planets were detached ; and 



that finally the chief portion of the hot 



cloud reached, by self-compression, the 



magnitude and density of our sun. The 



earth itself offers evidence of a fiery 



origin ; and in our day the hypothesis of 



I Kant and Laplace receives the indepen- 



I dent countenance of spectrum analysis, 



which proves the same substances to be 



common to the earth and sun. 



Accepting some such view' of the con- 

 struction of our system as probable, a 

 desire immediately arises to connect the 

 present life of our planet with the past. 

 We wish to know something of our 

 remotest ancestry. On its first detach- 

 ment from the central mass, life, as we 

 understand it, could not have been 

 present on the earth. How, then, did 

 it come there? The thing to be encou- 

 raged here is a reverent freedom a free- 

 dom preceded by the hard discipline 

 which checks licentiousness in specula- 

 tion while the thing to be repressed, 

 both in science and out of it, is dog- 

 matism. And here I am in the hands 

 of the meeting willing to end, but ready 

 to go on. I have no right to intrude 

 upon you, unasked, the unformed notions 

 which are floating like clouds, or gather- 

 ing to more solid consistency, in the 

 modern speculative scientific mind. But 

 if you wish me to speak plainly, honestly, 

 and undisputatiously, I am willing to do 

 so. On the present occasion 



" You are ordained to call, and I to come." 



Well, your answer is given, and I obey 

 your call. 



Two or three years ago, in an ancient 

 London College, I listened to a discus- 

 sion at the end of a lecture by a very 

 remarkable man. Three or four hundred 

 clergymen were present at the lecture. 

 The orator began with the civilisation of 

 Egypt in the time of Joseph ; pointing 

 out the very perfect organisation of the 

 kingdom, and the possession of chariots, 

 in one of which Joseph rode, as proving 

 a long antecedent period of civilisation. 

 He then passed on to the mud of the 

 Nile, its rate of augmentation, its present 

 thickness, and the remains of human 



