Explanatory Notes 125 



Page 84 



The ancient arguments of Zeno and other philosophers 

 are of the nature of a reductio ad absurdum, and were di- 

 rected against the trivial arguments of certain opposing 

 philosophers. The contention that motion cannot occur 

 because an object must be in either one place or another, 

 and the contention that a quick runner cannot pass a slow 

 one because the space between them is infinitely subdivis- 

 ible and some time is needed to cover every division were 

 not put forward as statements of fact absurdly contrary to 

 experience, but as arguments in favour of continuity of 

 space and against a static idea of time. All these ancient 

 paradoxes are really ingenious weapons of dialectic, and 

 are not to be taken as a sign of philosophic stultification, as 

 unfortunately they sometimes are. 



Page 86 



By a catalytic agent is signified in Chemistry something 

 which promotes a process or chemical change without 

 taking part in it: that is to say, a material substance which 

 by its presence facilitates a reaction while itself remaining 

 unchanged, apparently, or at any rate ultimately, inert. 

 Such instances are very common; one of the best known 

 being the action of manganese dioxide in the liberation of 

 oxygen from potassic chlorate. If every-day illustrations 

 are helpful, a broker may be called a catalytic agent in a 

 Stock Exchange transaction; and the same epithet might 

 be applied to a parson at a wedding. 



Now in the various interactions which occur between the 

 two great conserved entities, energy and matter, life and 

 living bodies seem to act in a catalytic fashion; for they 

 contribute no energy, but they direct it, and thereby facili- 

 tate operations that without their aid would have been 

 difficult or impossible. The simple act of lifting a fallen 



