OF SPACE 23.

WHAT ARE WE SUPPOSED TO KNOW ABOUT IT .-- The plain man may admit that he is not ready to hazard a definition of space, but he is certainly not willing to admit that he is wholly ignorant of space and of its attributes.

He knows that it is something in which material objects have position and in which they move about; he knows that it has not merely length, like a line, nor length and breadth, like a surface, but has the three dimensions of length, breadth, and depth; he knows that, except in the one circumstance of its position, every part of space is exactly like every other part, and that, although objects may move about in space, it is incredible that the spaces themselves should be shifted about.
Those who are familiar with the literature of the subject know that it has long been customary to make regarding space certain other statements to which the plain man does not usually make serious objection when he is introduced to them.

Thus it is said:-- (1) The idea of space is _necessary_.

We can think of objects in space as annihilated, but we cannot conceive space to be annihilated.