Let us always take the last co-ordinate to represent the time-measurement.

Then we should naturally say that (p_1, p_2, p_3) determined a point in space and that the event-particle happened at that point at the time p_4.

But we must not make the mistake of thinking that there is a space in addition to the space-time manifold.

That manifold is all that there is for the determination of the meaning of space and time.

We have got to determine the meaning of a space-point in terms of the event-particles of the four-dimensional manifold.