1891.] on the Implications of Science. 429 



The word " science " is now very commonly taken as being synony- 

 mous with " physical science." There is much to be said against 

 giving the word so narrow a meaning; nevertheless that meaning 

 will sufficiently serve my purpose this evening. Science then, thus 

 understood, is merely ordinary knowledge pursued with extreme care 

 — most careful observation, measuring, weighing, &c., together with 

 most careful reasoning as to the results of observations and experi- 

 ments, and also painstaking verification of any anticipations which 

 may have been hazarded. In this way our thoughts are made to 

 conform as accurately as may be with what we regard as the realities 

 they represent. 



The value and the progress of science are unquestioned. Many 

 foolish discussions are carried on in the world about us. But certainly 

 no one disputes or doubts the value of science or the fact of its 

 progress. The value of carefully-ascertained scientific truths will 

 not at any rate be disputed in this theatre, which has witnessed the 

 triumphs of the immortal Faraday, and which may justly claim to be 

 a very temple of science. And certainly I have no disposition to 

 undervalue it, who have loved it from my earliest years and devoted 

 such small powers as I possess to its service. I am profoundly 

 convinced that, since I can recollect, biological science has made 

 great progress, and I see grounds for absolute certainty now, about 

 many propositions in zoology which were doubtful or undreamed of 

 when I was a lad. 



We all then agree that science does advance. Nevertheless it is 

 obvious that such advance would be impossible if we could not by 

 observations, experiments, and inferences, become so certain with 

 respect to some facts, as to be able to make them the starting points 

 for fresh observations and inferences as to other facts. Thus, with 

 respect to the world we live in, most educated men are now certain 

 as to its daily and annual revolutions, as also that its crust is largely 

 composed of sedimentary rocks, containing remains, or indications, 

 of animals and plants more or less different from those which now 

 live. No one can reasonably deny that we may repose with absolute 

 confidence and entire certainty upon a variety of such assertions. 



But our scientific certainties have been acquired more or less 

 laboriously, and a questioning attitude of mind is emphatically the 

 scientific attitude. We ought never to rest satisfied about any 

 scientific inquiry the truth of which has not been demonstrated, 

 unless we find that it is one which we have no probable power to 

 answer — it would obviously be idle to occupy ourselves about the 

 shape or number of the mountains on that side of the moon which is 

 constantly turned away from us. 



Yet although doubt and inquiry are necessary in science, never- 

 theless doubt has its legitimate limits. Blind disbelief is scientifically 

 fatal as well as blind belief. We all know how apt men are, when 

 seeking to avoid one extreme, to fall into the opposite one, and it is 

 possible to get into an unhealthy condition of mind so as to be unable 



