106 SCIENCE PROGRESS 



of the universe. This difficulty is not to be met by denying the 

 reality of purpose. It is obvious that the structure of animals is 

 purposive ; and that many of the actions of mankind are directed 

 to a conscious end. All that we assert is that blind physical 

 forces are the true agency in the production of the phenomena 

 called purposive, as well as of all other phenomena. Their 

 purposive character is no more than a subjective attribute. To 

 other kinds of organic beings, other kinds of physical events 

 would be considered as purposive, while those which we now 

 consider purposive would be regarded as obviously mechanical. 

 Taking a physiological view, Mach observes that " Purposiveness 

 only comes in when the organic functions are resolved into one 

 another, when they are seen as interconnected, as not limited to 

 the immediate, as proceeding by way of detours." " By an 

 imperceptible modification in our thought, we can formulate 

 every teleological question in such a way as complete]}' to 

 exclude the conception of purpose." He points out further that 

 in ancient times purpose filled a much larger sphere than it does 

 at present. " Aristotle, for example, conceives heavy bodies as 

 seeking out their position ; Hero thinks that, from motives of 

 economy, nature conducts light by the shortest paths and in the 

 shortest times." To which we may add, as a more recent 

 example, that Bernardin de Saint-Pierre believed that melons 

 have ribs for the purpose of facilitating their consumption in 

 family circles. Dr. Mach epigrammatically describes animal life 

 as " nothing but combustion in complicated circumstances," for 

 it is a conflagration which " keeps itself going, produces its own 

 combustion-temperature, brings neighbouring bodies up to that 

 temperature and thereby drags them into the process, assimilates 

 and grows, expands and propagates itself." 



The Mirror of Perception, by Mr. Leonard Hall, is a work of 

 originality and ability, though we are wholly unable to agree 

 with its conclusions. He endeavours to show that the physical 

 world is not real, while the psychical world is ; the main object 

 of the book is to show that "the material world does not really 

 exist." It appears, in fact, that he has fallen into a very common 

 misunderstanding of the idealist position ; for the representation 

 of matter in terms of consciousness does not, properly under- 

 stood, involve any falling off in the "reality" of material 

 existence. It would be as reasonable to say that because colour 

 can be represented in terms of ethereal undulation, therefore it 



