• andrewk
    2.1k
    Sure, if one adopts an ontological perspective that says there is such a thing as absolute motion, rather than just relative motion, then one will have a problem. That seems a good reason not to adopt such a perspective.
  • Metaphysician Undercover
    5.5k

    I don't know what "absolute motion" would be, perhaps you mean absolute rest? In any case, it's a matter of a preferred perspective, the preferred rest frame. Do you agree that it's better to model the movement of the planets as movements relative to the sun as the rest frame, rather than as movements relative to the earth as the rest frame? If the preferred rest frame makes sense to you, then why not allow that there is an ideal, or best rest frame (absolute rest)?
  • andrewk
    2.1k
    If the preferred rest frame makes sense to you, then why not allow that there is an ideal, or best rest frame (absolute rest)?Metaphysician Undercover
    'Preferred' is a function of someone's mind - the person that prefers it. It is not ontological. For a given calculation there will often be a frame that makes the calculation simplest. Indeed, in GR, the biggest challenge is often in finding a frame that makes the calculations manageable. Again, that is a pragmatic, rather than an ontological consideration. There will be no universally preferred frame because a frame that is best for one purpose may be terrible for another. A laboratory-based frame is best for lab-based experiments. An Earth-centred frame is best for satellite management. A sun-centred frame is best for long-range space missions and predicting movements of solar system bodies other than the moon.

    For a cabin attendant serving meals in a commercial jet, the preferred frame is that of the jet, but for an air traffic controller directing the flight paths for the jet and other planes, the preferred frame is that of the control tower. Neither would want to use the frame of the other.
  • Metaphysician Undercover
    5.5k
    'Preferred' is a function of someone's mind - the person that prefers it. It is not ontological. For a given calculation there will often be a frame that makes the calculation simplest. Indeed, in GR, the biggest challenge is often in finding a frame that makes the calculations manageable. Again, that is a pragmatic, rather than an ontological consideration.andrewk

    The point though, is that "rest" is an ontological principle. Therefore the reason why one rest frame is preferred over another ought to be ontological rather than pragmatic. In scientific endeavours we ought to choose the best in relation to determining the truth, rather than what makes the calculations easiest..

    There will be no universally preferred frame because a frame that is best for one purpose may be terrible for another. A laboratory-based frame is best for lab-based experiments. An Earth-centred frame is best for satellite management. A sun-centred frame is best for long-range space missions and predicting movements of solar system bodies other than the moon.andrewk

    Now you base "best" in what "makes the calculations simplest" rather than true ontology. As I said, the easiest is not necessarily "the best". Your use of "best" here is not based in the intent of finding truth, but in the intent of making calculations easier.

    For a cabin attendant serving meals in a commercial jet, the preferred frame is that of the jet, but for an air traffic controller directing the flight paths for the jet and other planes, the preferred frame is that of the control tower. Neither would want to use the frame of the other.andrewk

    In many of our day to day procedures we settle for less than the best, that is obvious. But science ought to strive for nothing less than the best understanding of nature, and that is the truth. This requires adherence to solid ontological principles rather than pragmatic principles.
  • andrewk
    2.1k
    The point though, is that "rest" is an ontological principle. Therefore the reason why one rest frame is preferred over another ought to be ontological rather than pragmatic.Metaphysician Undercover
    Your claim that it is an ontological principle is what creates your problem. That's why it is unhelpful to adopt an ontology that includes such a principle, and unhelpful to regard 'rest' as an ontological concept instead of a scientific one that is used for calculations and predictions.
  • Metaphysician Undercover
    5.5k

    "Rest" is not a scientific principle. What rest is, has never been demonstrated empirically. That "rest" is relative to a frame of reference is an ontological principle adopted by relativity theorists, for the purpose of ease in calculations (as you described). That this is what "rest" really is has never been scientifically proven and therefore it is false to claim that this is a scientific principle.
  • andrewk
    2.1k
    I didn't say it was a scientific principle. I said it was a scientific concept. Rest is a definition. We say an object is at rest relative to another if the displacement vector from the first to the second is constant over time.

    Perhaps what you are challenging is whether it is ever possible for two objects to be perfectly at rest relative to one another. If so, fair enough. There will always e some tiny degree of relative movement, albeit imperceptible. All that matters in physics is whether such imperceptible movement can affect the predictions made by calculations based on an assumption that the object is at rest. In almost all cases, it doesn't.
  • Metaphysician Undercover
    5.5k
    Perhaps what you are challenging is whether it is ever possible for two objects to be perfectly at rest relative to one another. If so, fair enough.andrewk

    Yes, that's the issue, the inertial frame of reference is essentially arbitrary. Yet it is extremely important because inertia under Newton's first law represents the temporal continuity of existence, i.e. things that do not change as time passes. Newton's concept assumes that there is such a thing as an object with no forces acting on it, and this object will continue in time to be as it was. This a completely unrealistic assumption.

    The opposite perspective (which I believe is more realistic), is that the temporal continuity of existence requires an acting force (traditionally that would be God). So the law of inertia, upon which the "scientific" definition of rest is based, takes what had been attributed to the act of God, the temporal continuity of existence (things which stay the same as time passes), for granted. This taking inertia for granted, assumes that the temporal continuity of mass is necessary (cannot be otherwise), requiring no forces, while the opposite perspective assumes that a force is required for temporal continuity. But if the temporal continuity of mass is not necessary, (and there may be good evidence that it is not, in QM), then this so-called "scientific" definition of rest is completely off track. And so we would need to assume some force to fill the place of "the Will of God", in order to account for what we observe as rest.
  • andrewk
    2.1k
    The opposite perspective (which I believe is more realistic), is that the temporal continuity of existence requires an acting force (traditionally that would be God).Metaphysician Undercover
    That is a metaphysical perspective, not a physical one, and what you refer to as a force there is completely different from what a force means in physics.

    What you describe is Aquinas' belief that objects require a constant act of will to sustain their existence. I have no objection to that belief, but it is a belief that some hold and some do not, and that cannot be proved or disproved. Further, the act of will to which it refers is nothing like what Newton means by a force.
  • Metaphysician Undercover
    5.5k
    That is a metaphysical perspective, not a physical one, and what you refer to as a force there is completely different from what a force means in physics.andrewk

    The two distinct perspectives of temporal continuity, which I described, are both metaphysical perspectives, that's the point. That "inertia" is the one adopted by physics doesn't make it any less metaphysical.
12Next
bold
italic
underline
strike
code
quote
ulist
image
url
mention
reveal
youtube
tweet
Add a Comment

Welcome to The Philosophy Forum!

Get involved in philosophical discussions about knowledge, truth, language, consciousness, science, politics, religion, logic and mathematics, art, history, and lots more. No ads, no clutter, and very little agreement — just fascinating conversations.