But we are not thinking of logical definition so much as the formulation of the results of direct observation.

There is a certain continuity inherent in the observed unity of an event, and these two definitions of junction are really axioms based on observation respecting the character of this continuity.
[7] Cf.

_Enquiry_.
The relations of whole and part and of overlapping are particular cases of the junction of events.

But it is possible for events to have junction when they are separate from each other; for example, the upper and the lower part of the Great Pyramid are divided by some imaginary horizontal plane.
The continuity which nature derives from events has been obscured by the illustrations which I have been obliged to give.

For example I have taken the existence of the Great Pyramid as a fairly well-known fact to which I could safely appeal as an illustration.