366 THE RELATION OF MIND TO BODY 



species is particularly capable, within limits that vary with indi- 

 viduals, of learning to do infinitely varied and complex work, with 

 a constantly increasing degree of facility and skill. For that reason 

 my brain has done, not what the brains of my predecessors could 

 not do, but what they did not do (e.g. the work which results in 

 the knowledge of medicine). I believe, then, if we consider these 

 two facts together, the facts that human brains are much alike, but 

 human minds very different ; and if, moreover, we think in terms 

 of common sense and accept the theory of evolution, then we are 

 forced to conclude as the only course open to us, that mind is the 

 work, or rather part of the work, of the brain. 



