320 ON SENSATION AND THE UNITY OF 



possible. All that we know about motion is that 

 it is a name for certain changes in the relations of 

 our visual, tactile, and muscular sensations; and 

 all that we know about matter is that it is the 

 hypothetical substance of physical phenomena 

 the assumption of the existence of which is as 

 pure a piece of metaphysical speculation as is that 

 of the existence of the substance of mind. 



Our sensations, our pleasures, our pains, and 

 the relations of these, make up the sum total of 

 the elements of positive, unquestionable knowl- 

 edge. We call a large section of these sensations 

 and their relations matter and motion; the rest we 

 term mind and thinking; and experience shows 

 that there is a certain constant order of succession 

 between some of the former and some of the 

 latter. 



This is all that just metaphysical criticism 

 leaves of the idols set up by the spurious meta- 

 physics of vulgar common sense. It is consistent 

 either with pure Materialism, or with pure Ideal- 

 ism, but it is neither. For the Idealist, not con- 

 tent with declaring the truth that our knowledge 

 is limited to facts of consciousness, affirms the 

 wholly unprovable proposition that nothing ex- 

 ists beyond these and the substance of mind. 

 And, on the other hand, the Materialist, holding 

 by the truth that, for anything that appears to 

 the contrary material phenomena are the causes of 



