252 SCIENCE AND THE HUMAN MIND 



recent work leads away from and not towards a 

 complete and satisfying explanation of many vital 

 processes by physical principles. The organism, it is 

 argued, uses physical processes, as indeed is obvious, 

 but it does not necessarily, or even probably, follow 

 that the controlling agent itself is purely physical. 

 Moreover, in comparing a living being with a mechani- 

 cal machine, it must be remembered that the machine 

 " is no ordinary sample of the inorganic world. It is 

 an elaborated tool, an extended hand, and has inside 

 of it a human thought. It is because of these qualities 

 that highly complex machines come to be so like 

 organisms. But no machine profits by experience, 

 nor trades with time as organisms do." 



Indeed, many biologists, such as Driesch, Wolff, 

 Bunge, and J. A. Thomson, hold that the essence of 

 the problem is overlooked when attention is focussed 

 solely on the details of organic life, and the mechanical, 

 physical and chemical processes used therein. From 

 a more complete survey, they see reason to believe 

 that there are facts concerning organisms considered 

 as wholes which are not covered by any possible 

 extension of the domain of mechanics, physics and 

 chemistry. A living being, they believe, is autono- 

 mous ; it is in a sense an ultimate unit in nature, and 

 cannot be explained by a study solely of the detailed 

 phenomena of its parts and organs. Besides the 

 obvious purposefulness of the higher animals and 

 plants, a similar intention appears throughout all 

 living beings even from the first. 



As an instance of the phenomena on which they rely, 

 we may describe one of the many results of recent 

 work on the process of egg-development " Entwicke- 



