Alexander, Samuel (1859-1938) Space, Time and Deity:
The Gifford Lectures at Glasgow, 1916-1918, Vol I.
Book I. Space-Time
Chapter two. Perspectives and Sections of Physical Space-Time
No empty or immoveable Space
...But though empty of qualities Space and Time are always full. Space is full of Time and Time is full of Space, and because of this each of them is a complete or perfect continuum. If this might seem a quibble of words, which it is not, let us say that Space-Time is a plenum. Its density is absolute or complete. There is no vacuum in Space-Time, for that vacuum would be itself a part of Space-Time. A vacuum is only an interval between bodies, material or other, which is empty of body ; but it is full with space-time. Hence the old difficulty that if there were no vacuum motion would be impossible is without foundation, and was disposed of by Leibniz in answering Locke.* If it were completely full of material bodies with their material qualities there would be no room for locomotion of those bodies with their qualities. But it is only full with itself. Material bodies can move in this absolute plenum of Space-Time, because their motion means merely that the time-coefficients of their spatial outlines change.
* Nouveaux Essais, Preface (Erdmann, p. 199b, Latta, p. 385).
...For incompleteness at any moment is of the essence of Time. Neither strictly can the universe be said to be in motion as a whole. It is motion, that is in so far as it is expressed in its simplest terms.
Book I. Space-Time
Chapter two. Perspectives and Sections of Physical Space-Time
No empty or immoveable Space
...But though empty of qualities Space and Time are always full. Space is full of Time and Time is full of Space, and because of this each of them is a complete or perfect continuum. If this might seem a quibble of words, which it is not, let us say that Space-Time is a plenum. Its density is absolute or complete. There is no vacuum in Space-Time, for that vacuum would be itself a part of Space-Time. A vacuum is only an interval between bodies, material or other, which is empty of body ; but it is full with space-time. Hence the old difficulty that if there were no vacuum motion would be impossible is without foundation, and was disposed of by Leibniz in answering Locke.* If it were completely full of material bodies with their material qualities there would be no room for locomotion of those bodies with their qualities. But it is only full with itself. Material bodies can move in this absolute plenum of Space-Time, because their motion means merely that the time-coefficients of their spatial outlines change.
* Nouveaux Essais, Preface (Erdmann, p. 199b, Latta, p. 385).
...For incompleteness at any moment is of the essence of Time. Neither strictly can the universe be said to be in motion as a whole. It is motion, that is in so far as it is expressed in its simplest terms.