Reality: Fundamental Topics is Metaphysics

Chapter IX: Space

My aim in this chapter will be to come to conclusions about the metaphysics of space. One can hardly discuss space at all without in some manner engaging the physics of space. if certain kinds of results were reached, namely, results incompatible with what modern physics says about space, the character of the engagement would be critical, and, as i would see it, the metaphysical account would need to be very much on the defensive. it would be, in fact, almost certainly wrong. in any case, there would be for such an account a heavy burden of argument to try to show how physics has erred. As it happens, no such burden will fall upon the view defended here. (it will be found to be otherwise when i come, in the next chapter, to time.) At least, i think this is the case. the way it is usually put is that objects, or states or events involving them, are to be identified with reference to four dimensions, not three, as common sense and older physics had affirmed. in addition to the three spatial dimensions (intuitively the width, height, and depth the object or event occupies), a fourth temporal dimension is involved that may no more be separated from the three spatial dimensions than any of them may be separated from the other two. Still, even if this is granted, it may be noted that depth, for example, remains a distinct item—a reality distinct—from width, even if inescapably linked to it. But many popular and semi-popular expositions of relativity physics claim that the latter has actually dispensed with space and with time, in favour of space–time. taken strictly or literally, this is evidently to adopt a view analogous to the one taken about mind and matter by some varieties C H A P t e R i X Space 152 ReALitY: Fundamental topics in Metaphysics of neutral monism, according to which there is no such thing as either mind or matter, as supposed by common sense and quotidian experience, but rather a unitary kind of reality (whether a stuff, an event, or a state). (A distinct variety of neutral monism apparently holds that mind and matter are both real, only neither elementally so, for each is a form or case of a single underlying reality, which is itself strictly neither exclusively the one nor the other.) the relations of space, time, and space–time are not as clear as might be desired (or as popular expositions of relativity may suggest). We have provided two options. One is the view that space and time are both unreal, although a distinct item with a displacement “identity”1 to them is in their conceptual vicinity. the second is the view that space and time are both real, but are special cases or manifestations of a single thing, space–time (perhaps like the relations of ice and water vapour to water). Still a third option is a humbler position according to which space and time are interdependently linked so that—even though both are real and distinct—the one cannot be identified and characterized without reference to the other. in this third alternative it is space–time that will be the constructed or derivative entity, not space or time. Space–time would be a sort of aggregate or a codependent pairing of space and time. All of the foregoing will be viewed, largely accurately, as a simplistic and distorted account of what the evidence from common sense and the history of physics should yield. doubtless time-concepts and spaceconcepts arose long ago in the history of our species; and—more doubtfully but possibly—out of them emerged what we could call single concepts of space and time, constitutable as the common-sense notions of these things. these concepts may possibly be underdetermined, like so many common-sense concepts; or they are rounded intuitions of space and time that the folk achieved and that common-sense philosophy could excavate. in any case, newton produced models, a theoretical structure, including space and time conceived as independent items. A considerable measure of fit between folk-space and -time and newton’s theoretical versions was unquestionably intended by newton and accepted tacitly, at least as warranted by the readers of the Principia. newton’s conceptions are by no means conceived to stand or fall as a direct function of a perfect match. indeed, with sufficient general success of newton’s system as a whole, his...