ACHILLES AND THE TORTOISE. 



able to understand how the swifter can over- 

 take and pass the slower. Not, remember, to 

 understand that it can do so. That is easy 

 enough. But to understand in detail how it 

 can, in spite of the argument against Achilles. 



The illustration of the field shows us how 

 this can come about by our being so far re- 

 moved from the objects that things and move- 

 ments which are really discontinuous appear to 

 be continuous. 



But this result could equally well be brought 

 about by a sufficient smallness in objects which 

 are near to. A small object near to can sub- 

 tend as small an angle at the eye as a larger 

 object at a distance. It is only necessary, 

 then, to believe that objects consist of very small 

 particles or granules, to understand that changes 

 of state can pass over them which affect our 

 eyes, touch, ears, even aided by the most 

 delicate instruments, as continuous changes, 

 while in reality they are fragmentary and in- 

 terrupted. And this belief is one which science 

 has already, on other grounds, adopted. It is 

 generally accepted now that the particles or 

 granules of which substances consist are ex- 

 cessively small ; and, if not definitely laid 

 down as a conclusion, it is, at any rate, a con- 

 stant postulate of scientific thought, that they 

 are not infinitely small. 



In the preceding discussion one considera- 

 tion has been postponed. Our field consisted 



2*3 



