• substantivalism
    40
    Dear philosophy forum,

    For a while now i've been trying to better understand the metaphysics surrounding special relativity and other spacetime conceptions in relation to the reality/unreality of those entities. Basically whether I consider spacetime to be a real existent (independent of matter) substance or consider it relationally dependent on physical objects to manifest. Here is a link to the stanford encyclopedia of philosophy article on the topic if this is either new or unfamiliar.

    I've always been rather partial to relationism and in doing so treat spacetime as derivative of physical relations so it couldn't exist separate from them. Though, in the limited literature on the topic i've looked over when it comes to special relativity there is more popularity with a spacetime realist interpretation rather than a relationally reductive one. I find this to be rather strange as special relativity under some people's popular interpretations have talked about how the theory has abolished the absolute ticking throughout the universe that newton was partial too and accept that time or simultaneity needs to be physically defined or clarified. This interpretation, however, seems somewhat rare or purely presented as an analogy as I usually see spacetime realist interpretations of Minkowski spacetime or the Einstein interpretation of special relativity and in the spacetime realist position of Lorentz-Ether theory which changes the structure of spacetime to allow for universal simultaneity but still doesn't question the reality of such an entity.

    Has anyone here come across relational interpretations of special relativity or new theories of time/space that attempt to cement into its mathematics/metaphysics the idea of only relative change/interactions?
    In a sense the interactions between objects and their relative changes are what give rise to defining momentary senses of presentness/simultaneous occurrence but without those interactions it would be indeterminate whether something is present to you or not. Somewhat similar to this article I found on JSTOR where in he try's to clarify similar thoughts about this topic and argue against Sydney Shoemakers argument for time without change.

    Sincerely, a college freshman going on sophomore year
    1. Are you a spacetime realist or antirealist (Substantivalist or Relationist)? (2 votes)
        Substantivalism
          0%
        Relationism
        100%
        Mixture of both positions (feel free to clarify in the comments)?
          0%
        Third option (feel free to clarify in the comments)?
          0%
        I do not know (lack of academic familiarity or philosophical uncertainty)
          0%
  • noAxioms
    875
    I don't do polls, but I'm a relationist is probably far more ways than the one you describe.

    Yes, time has no meaning without regular change to define it. Space has no meaning without at least three locations so that it can be meaningfully expressed that A is closer to B than is C. Without physical objects to anchor those locations, they're just abstract geometry to us. I consider our reality to be 'real' only because it relates directly to me, however I might care to define 'me'.

    As for relational interpretations of special relativity, yes, I tend to favor RQM (Rovelli).
  • substantivalism
    40
    Thank you for the comment noAxioms.

    I agree mostly with what you have said and partially with the idea that the immediate reality we're familiar with is created through sensory inputs as well as processing within my brain/mental substances but I still have to admit that their are things that exist or are 'real' whether I or anyone else is directly experiencing them.

    I'll look into RQM, thank you for noting it.
  • noAxioms
    875
    Under RQM, experiencing something has nothing to do with it being real. There simply needs to be a relation, especially a measurement. So the apple exists relative to the rock iff the rock measures the apple in some way. The rock having conscious experience of the apple has nothing to do with it. That kind of thinking leads to solipsism. Think Wigner interpretation, which many people hold without knowing it, but even Wigner himself abandoned it due to the solipsism thing.
  • substantivalism
    40
    Yeah, solipsism really makes a philosopher run for the hills doesn't it.

    It was just the words being used by you such as 'me' that made me think you were taking a sort of idealist direction for your metaphysics but I was wrong there.

    Right now i'm looking at a cosmology and quantum gravity lecture by the guy you mentioned.
  • noAxioms
    875
    Yeah, solipsism really makes a philosopher run for the hills doesn't it.substantivalism
    Just because it's distasteful doesn't mean it's wrong. But I think there are serious logical problems with the solipsistic view, coupled with a personal bias against any sort of geocentrism, anthropocentrism, or any other view asserting us having a privileged status.

    It was just the words being used by you such as 'me' that made me think you were taking a sort of idealist direction for you metaphysics but I was wrong there.
    If I want to be formal, I had to find a definition of 'me' that didn't violate the law of identity, and it pretty much makes a hash of the way 'me' is used in everyday language. Language is littered with unstated premises, all of which I question (hence my user name), and most of which I cannot justify.
  • Enai De A Lukal
    112
    Wasn't Lee Smolin one of the more prominent/visible proponents of relationism? I seem to remember him citing it as a significant philosophical consideration/foundational principle for his cosmological natural selection hypothesis, in whatever popular work where he discusses it at length (the title escapes me, I read it some time ago). In any case I remember being a fan of his writing style, and being sympathetic to his remarks/arguments on that issue specifically- may be worth a look (if I remember the title I'll post it, but I imagine he covers similar territory in his other works, papers, lectures, etc.)
  • Enai De A Lukal
    112
    Here's a blog post on Smolin's relationism that looks pretty reasonable/serious at first blush (haven't read it yet myself, am in the process now but figured I'd post it)-

    Lee Smolin's Relationist (Meta)Physics
  • substantivalism
    40
    Just because it's distasteful doesn't mean it's wrong. But I think there are serious logical problems with the solopsistic view, coupled with a personal bias against any sort of geocentrism, anthropocentrism, or any other view asserting us having a privileged status.noAxioms

    I mean no disrespect or assume that because its "distasteful" it's therefore wrong but only that most philosophical viewpoints that would hold onto this as the center piece of their metaphysical viewpoint is both arbitrary or up to high scrutiny. We see eye to eye on the geocentrism and anthropocentrism of view points as I also find metaphysics which make us highly centered in the grander scheme of things likewise also highly suspect.

    If I want to be formal, I had to find a definition of 'me' that didn't violate the law of identity, and it pretty much makes a hash of the way 'me' is used in everyday language. Language is littered with unstated premises, all of which I question (hence my user name), and most of which I cannot justify.noAxioms

    It's like a sorites problem of sorts to attempt to specify where you end and the greater worldly environment begins.

    Here's a blog post on Smolin's relationism that looks pretty reasonable/serious at first blush (haven't read it yet myself, am in the process now but figured I'd post it)-

    Lee Smolin's Relationist (Meta)Physics
    Enai De A Lukal

    I sure will read up on this, thank you for your input.
  • Metaphysician Undercover
    7.2k


    Space and time, as well as space-time are the concepts human beings have developed to understand their surroundings. We understand our environment as things which are changing relations to each other, and are also changing in themselves. Since these concepts are derived from the fundamental principles which describe our surroundings as things, it doesn't make any sense to talk about space and time as being independent from things.

    There was a time when things were thought to move in space. Empty space was required in order that a thing could move, otherwise it would have to push on another thing which would push another an another, and nothing could move. But Einsteinian relativity conceives of things as moving relative to light. This allows that things might move through light without necessarily moving through space, and space and time as concepts, refer to the relations between things and light..
  • noAxioms
    875
    I mean no disrespectsubstantivalism
    None perceived. I agree with your comment that there is a general aversion to solipsism among philosophers, and I was just pointing out that the aversion itself is a poor reason to reject any view. I personally find the view self contradictory, and reject it for that reason.

    We see eye to eye on the geocentrism and anthropocentrism of view points as I also find metaphysics which make us highly centered in the grander scheme of things likewise also highly suspect.
    Yes, but again, I identify that as a personal bias, and therefore not good grounds for rejection. Who knows, maybe the universe is made for us. That possibility must be considered, but positing such doesn't seem to explain anything better than more plausible views.

    It's like a sorites problem of sorts to attempt to specify where you end and the greater worldly environment begins.
    Where I end (spatially, not temporally) is an interesting problem. It seems to be a purely abstract thing. The guy in the sci-fi show straps a time travel device to his wrist and it takes him and his clothes and briefcase to some other time, but doesn't take the nearby shrubbery. How does the device know what's you and what's not? It's intuitive to us, but in trying to tell a device how to do it, it turns out it isn't obvious at all.
    Where does a mountain stop? Most of them don't sit nicely on an otherwise flat surface that gives an obvious boundary delimiting mountain from the surface on which it rests.
    All these things are part of exploration of identity, but not particularly important to relationalism, which cares not so much what one defines as a 'system' or not.
  • substantivalism
    40
    Space and time, as well as space-time are the concepts human beings have developed to understand their surroundings. We understand our environment as things which are changing relations to each other, and are also changing in themselves. Since these concepts are derived from the fundamental principles which describe our surroundings as things, it doesn't make any sense to talk about space and time as being independent from things.

    There was a time when things were thought to move in space. Empty space was required in order that a thing could move, otherwise it would have to push on another thing which would push another an another, and nothing could move. But Einsteinian relativity conceives of things as moving relative to light. This allows that things might move through light without necessarily moving through space, and space and time as concepts, refer to the relations between things and light..
    Metaphysician Undercover

    So your perspective is more psychological and related to our conscious experiences. Is this a Berkeley or Kantian strategy you are gleaning from in treating spacetime as a fundamental psychological process but nothing more?

    Technically physical objects in special relativity move relative to other frames of reference and are always going to happen to observe that the top casual speed is c. The way out of a cartesian plenum is merely to assert that the properties inherent in certain physical objects may happen to include being co-present or ghost-like as photons are allegedly supposed to be able to pass right through each other. Though, maybe space is like a constantly changing Heraclitean fire, that in a similar manner to what Descarte had proposed, where in changes in position or form will influence the rest of the system cascading throughout.
  • substantivalism
    40
    None perceived. I agree with your comment that there is a general aversion to solipsism among philosophers, and I was just pointing out that the aversion itself is a poor reason to reject any view. I personally find the view self contradictory, and reject it for that reason.noAxioms

    Self-contradictory? I get that this philosophical viewpoint is not emprically well-founded and never could be (it would be consistent with any personal experience) but it always felt relatively possible.

    Yes, but again, I identify that as a personal bias, and therefore not good grounds for rejection. Who knows, maybe the universe is made for us. That possibility must be considered, but positing such doesn't seem to explain anything better than more plausible views.noAxioms

    I also agree with you on this and also hold this sort of personal bias especially on views of god in which I strongly disagree with anthropomorphic versions of such a concept as has been done in christian traditions.
  • noAxioms
    875
    So your perspective is more psychological and related to our conscious experiences. Is this a Berkeley or Kantian strategy you are gleaning from in treating spacetime as a fundamental psychological process but nothing more?substantivalism
    I said it is a psychological choice when I decide what components comprise a system or not. The physics of the relationalism has zero to do with this choice.

    I get that this philosophical viewpoint is not emprically well-founded and never could be (it would be consistent with any personal experience) but it always felt relatively possible.substantivalism
    I find the acquisition of new information to be a contradiction in the solipsistic idealist view. Say you find a tomb full of Egyptian writing and spend years trying to decipher it. You've memorized every character and could reproduce it at will from memory, yet you cannot read it. After years of study, you finally break the code and learn the language, and suddenly there is information that was always there, but suddenly is meaningful to you. That implies there is something out there that didn't come from you. I cannot dream of a coherent language that I don't yet understand. Something else has to have produced that tomb, which contradicts your experience being more fundamental than the noumena. That contradiction sinks the view in my opinion.
  • Kenosha Kid
    622
    It's weird that I voted relationism pretty much on instinct. GR is obviously a theory that compels a substantive picture of spacetime... the stuff bends, for goodness' sake! And yet, deep down, I've often wondered if the wavefunction of the entire universe gives a crap that we have a positional basis set to describe it with.
  • Enai De A Lukal
    112


    probably also worth noting e.g. "the private language argument" (from Wittgenstein's PI), which some interpretations take to show that solipsism is internally inconsistent or at least severely self-undermining. Its a contentious interpretation (as is whether that form of the argument works), but still probably worth noting in this context nonetheless. See the section on "the incoherence of solipsism" in the IEP entry on Solipsism for a brief (but fairly representative, imo) explication of this view.
  • Metaphysician Undercover
    7.2k
    So your perspective is more psychological and related to our conscious experiences. Is this a Berkeley or Kantian strategy you are gleaning from in treating spacetime as a fundamental psychological process but nothing more?substantivalism

    Sorry, I don't think I can answer this question.

    Technically physical objects in special relativity move relative to other frames of reference and are always going to happen to observe that the top casual speed is c.substantivalism

    Do you apprehend, as I do, that making the "top casual speed" (whatever you mean by "casual") as c, is to posit an absolute?
  • substantivalism
    40
    It's weird that I voted relationism pretty much on instinct. GR is obviously a theory that compels a substantive picture of spacetime... the stuff bends, for goodness' sake! And yet, deep down, I've often wondered if the wavefunction of the entire universe gives a crap that we have a positional basis set to describe it with.Kenosha Kid

    You're definitely not faulted for thinking GR prefers a substantivalist interpretation as Einstein, I believe, once thought his theories of relativity (special and general) vindicated relationism but were still full of situations in which solutions had absences of matter with still existent spacetime geometry so he later somewhat abandoned it I think. Relativity of the spacetime structure in more ways than galilean spacetime sadly did not mean the absence or emergence of spacetime itself. When you bring in quantum mechanics perhaps such a situation is much more amenable to the relationist position. . . depending on whether you adopt a background dependent or independent theory and the interpretation that follows from both camps.
  • substantivalism
    40
    Sorry, I don't think I can answer this question.Metaphysician Undercover

    Why? I mean both Berkeley and Kant held rather intriguing perspectives on the non-reality of spacetime which both were strongly influenced by their subjective and transcendental forms of idealism. Perhaps I was jumping at a collection of positions too quickly and yours is merely a form of naive realism mixed with modern day psychology.

    Do you apprehend, as I do, that making the "top casual speed" (whatever you mean by "casual") as c, is to posit an absolute?Metaphysician Undercover

    You mean an invariant? Special relativity has many invariants in the theory such as the spacetime interval and even the idea that while accelerations maybe feel or appear different depending on the frame of reference there is no question about who is accelerating, no relativity of accelerations. You either are or are not accelerating just like in real life you either are feeling a fictitious force and thusly accelerating or you are not but either way the symmetry of the situations is broken by dynamical considerations. In a sense this could be raised into an argument against a relationist persepctive of special relativity given it keeps that idea that accelerations, rotations, and the spacetime interval as rather asymmetric or invariant so you may be propelled to postulate a real existent spacetime that grounds these dynamical/kinematic invariants of our reality.

    I'll just note that a highly relativistic theory and an absolute theory of spacetime structure (like newtonian spacetime) does not decide or guarantee an answer in the relationist/substantivalist discussion though they do overlap. The first is a discussion of what is to be included in the structure of our spacetime (simultaneity, preferred rest frame, preferred direction, invariant casual speed, etc.) while the later regards the ontological status or grounding of such an entity.
  • litewave
    430
    We find a general definition of a space in mathematics: a space is a set of "points" with some added "structure". The points can be whatever but obviously they are not nothing. The structure (also called topology) is a certain collection of subsets of the underlying set of points, and this collection of subsets must satisfy certain conditions (namely, a union and an intersection of any of the subsets must belong to the collection too).

    The particular kind of space in general relativity (or "spacetime", which is a 4-dimensional space with time as a special 4th dimension) is a space with a curved metric topology where the points seem to be objects with quantitative properties we call energy and momentum, and these quantitative properties of every point are related to the quantitative properties of other points via regularities across space that we call laws of physics (in general relativity, Einstein field equations).

    If we regard objects possessing the properties of energy and momentum as "material" then the space in general relativity is made up of material objects. But apparently there can also be spaces with the same topology but with non-material objects as their points.
  • Kenosha Kid
    622
    When you bring in quantum mechanics perhaps such a situation is much more amenable to the relationist position. . . depending on whether you adopt a background dependent or independent theory and the interpretation that follows from both camps.substantivalism

    Indeed, relationism (of state rather than intervals) is gaining traction among quantum theorists following the recent Wigner's friend experiments, yet, even as a quantum theorist myself, I don't have much of an ontological position on it. Relativity is much more compelling in that regard but it isn't really an argument for substantivism, more a framework for working with models of a substantive-seeming spacetime.

    Even within that framework, there's no obvious reason why the spacetime picture need be fundamental. This is not a counter-argument in itself, but I'm reminded of the holographic principle in which the informational content of a volume, including the entire universe, can be encoded on its surface. (There are theoretical phenomena for which this cannot be true, and it still relies on the existence of a lower-dimensional spacetime.) When one opens the door to the idea that spatial dimensions can arise from more fundamental structures, one struggles to argue that the apparent spacetime we observe is substantive.
  • Enai De A Lukal
    112
    When one opens the door to the idea that spatial dimensions can arise from more fundamental structures...

    Isn't this the case in both string theory and LQG, that spacetime is an emergent feature of more fundamental structures (strings, networks, etc)?
  • Kenosha Kid
    622


    Spacetime is fundamental in string theory still, that is to say that string theory is an N-dimensional theory, with N depending on which flavour of string theory you prefer. The continuum of spacetime in LQG is emergent from networks but spacetime is if anything more substantive, being compromised of atomistic bits. It is the quantized spacetime of general relativity.
  • substantivalism
    40
    We find a general definition of a space in mathematics: a space is a set of "points" with some added "structure". The points can be whatever but obviously they are not nothing. The structure (also called topology) is a certain collection of subsets of the underlying set of points, and this collection of subsets must satisfy certain conditions (namely, a union and an intersection of any of the subsets must belong to the collection too).

    The particular kind of space in general relativity (or "spacetime", which is a 4-dimensional space with time as a special 4th dimension) is a space with a curved metric topology where the points seem to be objects with quantitative properties we call energy and momentum, and these quantitative properties of every point are related to the quantitative properties of other points via regularities across space that we call laws of physics (in general relativity, Einstein field equations).

    If we regard objects possessing the properties of energy and momentum as "material" then the space in general relativity is made up of material objects. But apparently there can also be spaces with the same topology but with non-material objects as their points.
    litewave

    In your interpretation the spacetime points are coexistent, co-present, and coincide ontologically with the objects in question. I would preface that this is an intriguing interpretation as it seems to basically be a form of super-substantivalism in which an entity is exactly identical to that in which it's located at, if i'm getting at your interpretation correctly. It's an intriguing possibility and there is opposition to such a possibility along with other positions in the mereology of location where other interpretations consider it more that there are material objects located at real existent spacetime points but they are not identical to those points. It's the difference between saying objects with energy/momentum permeate spacetime versus having parts of spacetime itself behave in certain ways that mimic the energy/momentum/behavior of fundamental particles.
  • substantivalism
    40
    Indeed, relationism (of state rather than intervals) is gaining traction among quantum theorists following the recent Wigner's friend experiments, yet, even as a quantum theorist myself, I don't have much of an ontological position on it. Relativity is much more compelling in that regard but it isn't really an argument for substantivism, more a framework for working with models of a substantive-seeming spacetime.

    Even within that framework, there's no obvious reason why the spacetime picture need be fundamental. This is not a counter-argument in itself, but I'm reminded of the holographic principle in which the informational content of a volume, including the entire universe, can be encoded on its surface. (There are theoretical phenomena for which this cannot be true, and it still relies on the existence of a lower-dimensional spacetime.) When one opens the door to the idea that spatial dimensions can arise from more fundamental structures, one struggles to argue that the apparent spacetime we observe is substantive.
    Kenosha Kid

    Special relativity alone is not an argument for a substantival spacetime but taken with other philosophical considerations such as assuming the non-existence of spacetime would entail there being few absolute or invariant dynamical asymmetries/invariants to physics. This is because these features could then be argued to be grounded in something other than matter itself.

    Of course there doesn't seem to be any conceptual necessity that spacetime be fundamental in any sense of the word nor possess certain exact features. It's not logically necessary and is a rather contingent affair in general.

    Though, it may be difficult to say in what manner spacetime is not substantive because if spacetime truly is emergent or reductive to other fundamental properties then it's perhaps truly non-existent in an eliminativist sense. If we cannot reduce spacetime to physical properties but the two always seem to have to coexist the discussion then becomes much vaguer.
  • Kenosha Kid
    622
    Though, it may be difficult to say in what manner spacetime is not substantive because if spacetime truly is emergent or reductive to other fundamental properties then it's perhaps truly non-existent in an eliminativist sense.substantivalism

    I wouldn't go that far. Spacetime is at least well-defined, indeed a lot of mathematics depends on it, so I think at worst emergent.

    One thing that popped into my head was that in non-relativistic QM, position is an operator (a thing you physically measure) and time is a parameter (a thing you specify). There are time operators but they do not enter into the evolution of the wavefunction.

    In relativity, space and time are on equal footing, so in relativistic QM, position is demoted from an operator to a parameter. One could read that as meaning that spacetime is less physical in relativity than Newtonian mechanics perhaps.
  • substantivalism
    40
    In relativity, space and time are on equal footing, so in relativistic QM, position is demoted from an operator to a parameter. One could read that as meaning that spacetime is less physical in relativity than Newtonian mechanics perhaps.Kenosha Kid

    Less physical in QM but not exactly the case in special relativity simpliciter. If anything special relativity alone is just as substantivalist as newtonian spacetime was interpreted to be long ago barring any other dynamically focused interpretations of the theories in question.
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