Instantaneous space must be an assemblage of abstractive elements considered in their mutual relations.

Thus an instantaneous space is the assemblage of abstractive elements covered by some one moment, and it is the instantaneous space of that moment.
We have now to ask what character we have found in nature which is capable of according to the elements of an instantaneous space different qualities of position.

This question at once brings us to the intersection of moments, which is a topic not as yet considered in these lectures.
The locus of intersection of two moments is the assemblage of abstractive elements covered by both of them.

Now two moments of the same temporal series cannot intersect.

Two moments respectively of different families necessarily intersect.