Space, Time, and Matter: A Note
It is sometimes said, jokingly, that it is fortunate time exists or else everything would happen simultaneously. We could also say, jokingly, that it is fortunate space exists or else everything would have to be in the same place. If space existed but time didn’t, different events could occur at distinct locations but simultaneously, thus allowing for a multiplicity of events; while if time existed but space didn’t, different objects could exist at distinct times but all in the same place, thus allowing for a multiplicity of objects. But if neither space nor time existed, then everything would have to occupy a single place at a single time. All of the physical universe would have to exist at one place, and all of history would have to occur at one time. Of course, this is absurd: there could not be such multiplicities at a single place and time (a space-time point). It is the existence of space and time that makes the multiplicity of objects and events possible; they make room for the Many. When God created space and time he did so in order to allow for the possibility of many objects and many events—since you can’t have the latter without the former.
Part of the humor in the remark is that if there were no space and no time then there would not be oneplace and onetime: there would be noplaces and notimes. If that were so, there would be noobjects and noevents either—not the totality of them squeezed into one spatiotemporal location. Space and time are the preconditions for objects and events to exist at all. But the remark raises the possibility of there being a single place and a single time—which itself sounds fishy. Could there be just one place and one time in isolation? Could there be a world in which the area occupied by my head now exists but no other area of space exists, and in which last Tuesday exists but no other stretch of time? There is just one cubic foot of space and twenty-four hours of time, with nothing, so to speak, on either side.
Surely that is absurd: these entities must be embedded in a wider totality of places and times—the things we call Space and Time. Concerning this particular unit of space and time, itcould not exist without other units of space and time. Indeed, it is plausible to claim that it could not exist without allof space and time. For thispart of space and time to exist therestof space and time must exist. If space and time are infinite as a matter of metaphysical necessity, then the existence of any portion of them implies the existence of an infinite dimension: the being of one unit of space or time requires the being of infinitely many such units. This is a kind of extreme holism, analogous to the (alleged) holism of belief: just as one belief cannot exist in isolation, but requires the existence of many other beliefs, so one place or one time cannot exist in isolation, but require the existence of (infinitely) many other places or times. Places and times are essentially parts of a spatial and temporal totality, not isolable detachable atoms. They cannot wander off on their own.
What about matter? Here we find a sharp contrast: for units of matter canexist in lonely isolation. A particular collection of particles, say a small meteorite, could exist without any other matter existing—it doesn’t need to be surrounded by other small meteorites. Concerning this particular collection, itcould exist without any of the rest of the matter of the universe existing. There is a possible world in which all of the actual world’s matter has been removed leaving only this solitary piece. Bits of matter don’t imply other bits of matter. Bits of matter are not essentially parts of a totality of matter, extending outwards indefinitely. They are not subject to the “holism of the material”, analogous to the “holism of the spatial and temporal”. There is thus a deep ontological difference between matter, on the one hand, and space and time, on the other. Therefore matter cannot be some kind of configuration or condensation of space and time; and space and time cannot be some kind of rarefaction of matter. We cannot reduce one category of being to the other category: matter is not space and time congealed, and space and time are not matter etiolated.
Matter is conceived as an occupantof space and time—something that “takes up” space and time. Matter is not essentially joined to other matter: one occupant does not entail the existence of another occupant. The occupants are separate existences, not just in being numerically distinct, but also in not being necessarily connected. But units of space and time are not separable occupants, modally unconnected: they are essentially elements of a whole and cannot be removed from that whole. It is not an essential property of any piece of matter that neighboring pieces of matter should exist (the existence of Earth does not logically require the existence of Mars), but it is an essential property of places and times that neighboring places and times should exist (the place of my head now implies the existence of contiguous places, and last Tuesday requires Monday and Wednesday). Places don’t occupyspace and moments don’t occupytime: consequently they cannot be sundered from other such occupants. Space and time don’t necessarily contain specific bits of matter, but they do necessarily contain specific bits of space and time—they are made up of places and times. Places and times are not atoms of space and time in the way physical particles are atoms of matter: the latter can be modally separated from each other, but the former cannot. Time is never short and space is never narrow, but matter can be rare and small.