We have as yet invented no instrument that will make directly perceptible to the finger tip an atom of hydrogen or of oxygen, but the man of science conceives of these little things as though they could be perceived.
They and the space in which they move--the system of actual and possible relations between them--seem to be related to the world revealed in touch very much as the space revealed in the field of the microscope is related to the space of the speck looked at with the naked eye.
Thus, when the thoughtful man speaks of _real space_, he cannot mean by the word only the actual and possible relations of arrangement among the things and the parts of things directly revealed to his sense of touch.

He may speak of real things too small to be thus perceived, and of their motion as through spaces too small to be perceptible at all.
What limit shall he set to the possible subdivision of _real_ things?
Unless he can find an ultimate reality which cannot in its turn become the appearance or sign of a further reality, it seems absurd to speak of a limit at all.
We may, then, say that real space is infinitely divisible.

By this statement we should mean that certain experiences may be represented by others, and that we may carry on our division in the case of the latter, when a further subdivision of the former seems out of the question.

But it should not mean that any single experience furnished us by any sense, or anything that we can represent in the imagination, is composed of an infinite number of parts.
When we realize this, do we not free ourselves from the difficulties which seemed to make the motion of a point over a line an impossible absurdity?
The line as revealed in a single experience either of sight or of touch is not composed of an infinite number of parts.

It is composed of points seen or touched--least experiences of sight or touch, _minima sensibilia_.