Maudlin and the spatiotemporal shifts

Hello all, 

I've limited the scope of this post to Maudlin's conception of Newtonian substantivalism and how it copes with the static and kinetic spatiotemporal shift arguments. I had difficulty grasping the content of sct. 4, and as such I think it would be more productive to focus on sct. 3, which is relatively straight forward but yields some interesting questions and responses. I'm not entirely sure of the best way to structure this, so I will briefly summarise the text, highlighting any questions or concerns that occurred to me. 

Maudlin offers a view on the classical debate of which holds that the key issue under consideration, the fact that Newtonian absolute space has a "metaphysically distasteful" character of ontologically distinct but empirically identical circumstances, is brought about by a fundamental misunderstanding and subsequent misuse of the arguments. He claims that the weight of Leibniz' spatiotemporal shift arguments is down to a fallacious equivocation, and that upon investigation into their structures, one finds that they are essentially different, and therefore cannot be legitimately appealed to. 

The arguments in brief: In a substantivalist universe, where spatiotemporal properties of objects are defined absolutely in relation with absolute space, and defined locally in relation with one another, a static shift in time and/or space would essentially be unnoticeable, since every observation made before and after the shift would be identical. Similarly, a kinematic shift, in which the universe in its entirety would undergo motion with repeat to absolute space, would also be unnoticeable for the same reason. If the relations between bodies would not change, the observations made within such a shifted universe would still hold as they had before, and therefore the two universe pre-and-post-shift would be indiscernible from one another. Following the Principle of the Identity of Indescernibles, the two universes would be identical. "In short, both the static and kinematic shifts (...) would result in ontologically distinct but observationally indistinguishable states of affairs."

Maudlin goes on to expose the failure of the argument, which rests in an “illusions engendered by imprecision concerning the notion of observationally indistinguishable states of affairs.” The key here is that what is observationally indistinguishable in the case of the kinematic shift is not necessarily so in the case of the static shift. Essentially, within Newtonian space-time, observation is possible if there is a change in spatiotemporal property with respect to anything other than absolute space, so if two shifted universe states differ only with respect to absolute space, the difference will not be observable, and therefore the states will be observationally indistinguishable. What this seems to come down to is that in the case of a kinematic shift, we can say that we part of the actual world, but there are certain aspects of it that are unknowable.

Similarly, in the case of the static shift, there will be no way to observe certain spatiotemporal properties that would help us identify which state of affairs we are part of. Maudlin then poses the following question: if the entire universe were to shift statically in space or time, what could we say about the actual state of the universe? In the kinematic case, he says, physical questions about the actual nature of the universe can be asked but not necessarily answered, whereas in the static case they cannot even be asked in the first place without indexically picking out a spatiotemporal location, and identifying the occupant of that location is a physical question that can be answered.

Maudlin provides an example for this which amounts to the claim that it knowledge of the spatiotemporal locations of things is presupposed in referring to them. Were the universe shifted statically 15 billion years into the future, he says, it is possible that someone just like him would be sitting in the same place writing the same words, however the indexicals used in his writing would ensure that the referents of his utterances would not be the same. In that sense, it is an error on the part of Leibniz to assume that a static shift would be undetectable; not because it could be observed, but because the observer would no longer be around to observe it.

I agree with this to some degree in the case of a temporal shift, but I am not convinced the same applies in the spatial shift. It is possible that the entire universe from my point of view could shift spatially billions of lightyears to the left, but if the relative distances and positions between the occupants of the universe do not change, that is, were their positions to change only with respect to “absolute” space, then the spatial location contained in the meaning of my utterances of “here” or “there” would also have to change, and there would be no observation possible that would make me aware of that. In other words, it is true that “here” means two different things pre-and-post-shift, but it seems dubious that my knowledge of that should track the shift, as it were. In Maudlin’s words, “We can (…) formulate meaningful counterfactuals about worlds where everything would be displaced from its actual location, but we can also be assured that they are counterfactuals.” Where does this assurance come from? It seems to me that taking spatiotemporal properties as counterfactuals presupposes that the actual state can be discerned through observation, which is precisely what remains to be shown.

Where Maudlin loses me is in his conception of what a static shift would be like, so to close this post I would like to examine the ways in which this is conceivable. The point of the static shift argument is to show that in absolute space, a spatiotemporal change of position of the entirety of the universe, that is, everything that exists within it, with respect to absolute space, would be unnoticeable, and that therefore a view of space-time which holds on to absolute space but admit the possibility of an infinity of possible universes. But if we ignore PII (which, as Maudlin notes, is no longer taken seriously), it seems that this is not a problematic consequence.