TENDENCIES OF MODERN PHYSICS 51 



is a rather complicated syllogism, so it is better to 

 reduce it to simpler terms, as follows : true matter is a 

 plenum; by definition, a plenum is that which is full of 

 matter ; therefore matter is true matter. Such reason- 

 ing should convince anyone that, no matter how we 

 may wrap up our logic, we cannot explain those things 

 which we must use as a means of explaining other 

 phenomena. The ordinary man expresses this by the 

 saying, we cannot lift ourselves by our own bootstraps. 

 Are not such hypotheses in the same class as perpetual 

 motion and squaring the circle? 



But even on the scientific side, this hypothesis is not 

 satisfactory. Every theorist acknowledges that sci- 

 ence is founded ultimately on our sense perceptions, 

 and this fact should warn us that the attribute elec- 

 tricity is not a substance. The phrase, to electrify 

 matter, has a well-defined meaning, because we know, 

 by experience, that a body when rubbed exhibits a 

 force which was not evident previously. We also know 

 that we may select two different bodies, which will 

 each show this electric force but of such opposite 

 characteristics that their mere contact reduces the 

 whole force to zero. Our knowledge of electricity 

 comes only by this manifestation of electric force, so 

 that if electricity were a substance we are reduced to 

 this anomaly, that the addition of substance to sub- 

 stance may result in less substance. This attractive 

 force is the simple and fundamental fact in regard to 



