SPACE, TIME 295 



in itself. This is unquestionably due to the intimate associa- 

 tion of both space and time with events, and applies also 

 to extents of space and to durations of time. A mile which is 

 "full," i.e., contains a great variety, seems shorter than a 

 mile which is "empty"; and an hour which contains exciting 

 events seems shorter than an hour which is filled with monot- 

 ony. From the empirical point of view the inch on the end 

 of the nose is actually longer than the inch on the yard- 

 stick; and the one second interval before some impending 

 catastrophe is really longer than a one second interval 

 drawn from ordinary life. Events vary in importance and 

 significance, and space and time take on corresponding 

 heterogeneities. Empirical space and time exhibit hummocks 

 and irregularities, compressions and expansions, twistings 

 and deformations. 



Anisotropy. According to the dimensional interpretation 

 empirical space is probably not isotropic. The conclusion 

 here depends partly upon whether one concerns himself 

 with visual, tactual, auditory, or motor space. Due to the 

 fact of eye convergence, the near-far dimension is probably 

 qualitatively distinct from the up-down dimension or the 

 right-left dimension. The omnipresence of gravitation gives 

 to the up-down dimension a qualitative distinctness. The 

 essential freedom in one's right-left and near-far movements, 

 as compared with the limitations in his movements up 

 and down, contribute further to the anisotropy. Much of 

 the difficulty in one's visualization of the other side of the 

 earth is due to the anisotropy of the up-down dimension. 

 According to the directional interpretation, empirical space 

 is not so clearly anisotropic. It is doubtful whether there 

 is any fundamental distinction between the near-far and the 

 far-near directions, and between the left-right and the right- 

 left. The up-down direction is, I believe, sharply distin- 

 guished from the down-up — due, again, to the fact of gravi- 

 tation; one moves up with great effort, but one moves down 

 with ease. Probably the directional features of space are 

 intimatelv associated with movement; to the extent to 



