534 SCIENCE PROGRESS 



of course that the attempts were purposely made as experiments 

 in proof of any theory whatever. The guiding purpose has 

 always been man's own advantage : the fancier's love of his 

 hobby or the breeder's profit. But is it of the essence of 

 an experiment that it should be purposely made as such to 

 prove a theory? I think not. All that is really essential is 

 a sufficient control of the phenomena and a sufficient observa- 

 tion and the record of the sequence of events, all of which we 

 undoubtedly have. In a word, it is possible to prove theories 

 by experiment without knowing that we are doing so ; this 

 is what has been done. Breeding is the experimental produc- 

 tion of variety by the selection of variations. 



To see the force of this contention, it is only necessary 

 to suppose that the human intellect, instead of being, as it is, 

 far stronger on the practical and inductive side than on the 

 theoretical and deductive, so that practice usually precedes 

 theory, had been stronger on the theoretical than on the 

 practical side and that in 1858, when the theory of Natural 

 Selection was enunciated, the practice of domestication of plants 

 and animals or rather, let us say, their improvement by selection, 

 had not been begun. What would biologists then have said ? 

 Clearly they would have reasoned : " If this theory be true ; 

 if nature have indeed raised up highly developed and specialised 

 kinds of life from the simplest or from comparatively simple 

 forms by destroying out of each generation the weaker members 

 and reserving the stronger to continue the race ; if plants and 

 animals differ in their fitness to cope with their surroundings 

 and it be on the average the fitter that survive and multiply, 

 transmitting their superior fitness to their descendants : then 

 man too, in his comparatively limited way, even in the short 

 time at his disposal, must be able to produce proportionate 

 results. Therefore, if we breed our cows only from the best 

 milking cows and from bulls that are proved sires of good 

 milkers, if we set aside exceptionally large-grained specimens 

 of wheat as seeds for succeeding seasons, we shall be able 

 to improve both cattle and wheat, slowly no doubt but to 

 an indefinite extent in the selected characters. The experiment 

 is doubtless absurd but it is harmless and the failure to 

 produce results, say in the course of a century, will go some 

 way to disprove the theory and clear the air of this crack- 

 brained and pernicious nonsense." The proposal would 



