ajb Posted June 25, 2016 Posted June 25, 2016 The paper would bend but would the lines on it bend with respect to the paper? The lines are part of the paper. Strange's idea is better. You can use lasers to 'track out' the curvature of space-time.
swansont Posted June 25, 2016 Posted June 25, 2016 The lines are part of the paper. Strange's idea is better. You can use lasers to 'track out' the curvature of space-time. But the best you can say is that it acts like it is curved. Not that it actually is curved.
StringJunky Posted June 25, 2016 Posted June 25, 2016 (edited) The only access to what "physically exists" is through our measurements and observations. If our measurements and observations are consistent with curvature, then that is the closest we can get to saying curvature is "real". To get any further than that, you would have to define more precisely what you mean by "physically exists" or "real" if they don't mean "what we observe and measure". Asking if curvature 'exists' is the same as asking if distance exists or voltage. More generally, one could ask "Do properties exist". Edited June 25, 2016 by StringJunky
Strange Posted June 25, 2016 Posted June 25, 2016 Asking if curvature 'exists' is the same as asking if distance exists or voltage. Indeed. They are all things we can measure. "Reality" is something else. Maybe.
StringJunky Posted June 25, 2016 Posted June 25, 2016 Indeed. They are all things we can measure. "Reality" is something else. Maybe. Therefore, curvature of spacetime exists; light bends. The underlying reality of what causes that is, as you say, something else.
swansont Posted June 25, 2016 Posted June 25, 2016 Indeed. They are all things we can measure. "Reality" is something else. Maybe. Measure, and interpret using a model. Which is why reality may be something else.
Strange Posted June 25, 2016 Posted June 25, 2016 How unsatisfying Can you explain why? I'm not sure what else you expect. This is just a fact of life: we can only ever know about the world by what we measure - that might just be using our eyes and ears to interpret our surroundings, or taking accurate measurements with instruments to test a theory. All we have, in both cases is our observations. That is as close to reality as we can ever get.
geordief Posted June 25, 2016 Author Posted June 25, 2016 Measure, and interpret using a model. Which is why reality may be something else. Is it important for a theoretical scientist to have a grasp of the two concepts ,the "model" and the "modelled" ? Can a confusion of the two cloud the thought process or is this not an important consideration aside from being interesting in its own right? Can you explain why? I'm not sure what else you expect. This is just a fact of life: we can only ever know about the world by what we measure - that might just be using our eyes and ears to interpret our surroundings, or taking accurate measurements with instruments to test a theory. All we have, in both cases is our observations. That is as close to reality as we can ever get. No one has mentioned that the sensory equipment of the body can be considered as a biological measuring machine? Is that a consideration?
Strange Posted June 25, 2016 Posted June 25, 2016 No one has mentioned that the sensory equipment of the body can be considered as a biological measuring machine? Is that a consideration? Absolutely. I see no difference between our daily experience and science in this respect. They both use observations to build models of the world around us. Science is just a bit more rigorous about accuracy and subsequent testing of the model.
swansont Posted June 25, 2016 Posted June 25, 2016 Is it important for a theoretical scientist to have a grasp of the two concepts ,the "model" and the "modelled" ? Can a confusion of the two cloud the thought process or is this not an important consideration aside from being interesting in its own right? I'm not a theorist, so I have no idea how much this comes into play. For someone doing science, success is having a model work. So I imagine any thoughts along those lines are important if they help construct the model. No one has mentioned that the sensory equipment of the body can be considered as a biological measuring machine? Is that a consideration? We already know that the human is a basic measuring machine, but limited in usefulness. In most cases we can only sample a narrow range of events and it's hard to calibrate us.
geordief Posted June 25, 2016 Author Posted June 25, 2016 We already know that the human is a basic measuring machine, but limited in usefulness. In most cases we can only sample a narrow range of events and it's hard to calibrate us. But it does feed into our perception of what is ..."what" and so ,although rudimentary in comparison to our exquisite machines does occupy an extraordinarily "strategic" position .
swansont Posted June 25, 2016 Posted June 25, 2016 But it does feed into our perception of what is ..."what" and so ,although rudimentary in comparison to our exquisite machines does occupy an extraordinarily "strategic" position . I think most scientists and many non-scientists are fully aware of the fact that things exist that we can't see or otherwise perceive. So from a data collection standpoint, there is nothing extraordinary about humans. It's far easier to fool a human than to fool the tools we regularly use to do measurements.
geordief Posted June 25, 2016 Author Posted June 25, 2016 I think most scientists and many non-scientists are fully aware of the fact that things exist that we can't see or otherwise perceive. So from a data collection standpoint, there is nothing extraordinary about humans. It's far easier to fool a human than to fool the tools we regularly use to do measurements. The tools are just extensions of our biological sensory apparatus. Without this biological sensory apparatus to interpret* the measurements the tools are just so many assemblies of objects.....The biological apparatus is like the gate keeper.,or perhaps the slowest marcher at whose pace the army marches. * and to build the tools
Thorham Posted June 25, 2016 Posted June 25, 2016 Can you explain why? That at some point you're going to have to accept that things are simply as they are seems obvious, but I don't like the idea of us already being at that point. We've only just gotten started! It would sure be nice to know a little more.
swansont Posted June 25, 2016 Posted June 25, 2016 The tools are just extensions of our biological sensory apparatus. Without this biological sensory apparatus to interpret* the measurements the tools are just so many assemblies of objects.....The biological apparatus is like the gate keeper.,or perhaps the slowest marcher at whose pace the army marches. * and to build the tools Extensions, yes. That *massively* extend the capabilities of our biological sensory apparatus. Without which we would be stuck without the last 100 years or more of scientific achievement.
Strange Posted June 25, 2016 Posted June 25, 2016 That at some point you're going to have to accept that things are simply as they are seems obvious, but I don't like the idea of us already being at that point. We've only just gotten started! It would sure be nice to know a little more. We have always been at that point and always will be. When people first saw the stars as lights on a sphere, that was reality for them. When we have a deeper theory of quantum gravity, then that will be our reality.
Thorham Posted June 25, 2016 Posted June 25, 2016 (edited) We have always been at that point and always will be. When people first saw the stars as lights on a sphere, that was reality for them. When we have a deeper theory of quantum gravity, then that will be our reality. What I mean is the point where there isn't anything more to figure out. Edited June 25, 2016 by Thorham
Strange Posted June 25, 2016 Posted June 25, 2016 What I mean is the point where there isn't anything more to figure out. I don't think we will ever get to that point.
StringJunky Posted June 25, 2016 Posted June 25, 2016 What I mean is the point where there isn't anything more to figure out. Getting a grip on a reality is like chasing a rainbow; it will always be out of reach but we can get closer. That will keep everybody busy.
Strange Posted June 25, 2016 Posted June 25, 2016 Getting a grip on a reality is like chasing a rainbow; it will always be out of reach but we can get closer. That will keep everybody busy. We can get more accurate models, but that doesn't necessarily mean we are closer to "reality".
StringJunky Posted June 25, 2016 Posted June 25, 2016 We can get more accurate models, but that doesn't necessarily mean we are closer to "reality". But the more accurate the model and the wider the domain it can accurately describe it's probably going in the right direction to get nearer the underlying nature. I don't think one can get closer than what one measures and the more parameters that are discovered the better the description. The more complete the description the closer one is. When you think fundamentally about the real world what is reality but the sum of its behaviour; there's no actual physicality in the classical sense is there at that depth of enquiry?
TakenItSeriously Posted June 25, 2016 Posted June 25, 2016 (edited) ...In my opinion the answer to this question is, briefly, this: as far as the propositions of mathematics refer to reality, they are not certain; and as far as they are certain, they do not refer to reality. ...Albert Einstein, "Geometry and Experience", 1921Wow, Ive been looking for a quote ever since I saw that documentary but searching for quotes without knowing how it was stated is next to impossible for someone who's been quoted probably more than any man in history. Edited June 25, 2016 by TakenItSeriously
Thorham Posted June 26, 2016 Posted June 26, 2016 I don't think we will ever get to that point. Let's hope not.
disarray Posted June 26, 2016 Posted June 26, 2016 (edited) Kant too, as I recall, thought we could get closer and closer to reality, the noumena, as opposed to our "phenomena", without ever being able to experience "it." given current ideas about the ephemerality of an electron, for example, with it's "superposition" and wave/particle states, etc., that should not surprise us. But whatever is beyond the reach of our senses and sensory aids (e.g. particle accelerators and electron microscopes)is still as real and "physical" as the "things" we assume we experience directly, or rather, as physical as our mental images, which is , in the final analysis, all we ever have. But perhaps one limit will be that our aiding tools use (or rather"are")similar subatomic or submolecular things as the things we are attempting to describe and measure, e.g., trying to see an electron with electron microscope or "measure/observe" electrons in double slit experiment without our instrument disturbing the electron. It is a tautology that we can't see, hear (etc.) that which we can't. Nor can we assume that it would be possible for some animal or creature to experience things that we can't now. For example, we might assume that because a dog can hear higher pitched sounds than we can, or that if only we were like some snakes or bats or deep ocean creatures we could detect infrared heat. Perhaps, we then assume that some living creature (or perhaps a hypothetical god) could experience anything that exists, even though our senses only allow us to experience a slice....about a trillionth (I have read, can't find quote right now) of the electromagnetic spectrum. But even if we could experience every possible wave buzzing around in the universe, we still would not experience more than our senses allow us to....and as Kant seminally pointed out, our brain reorganizes and projects information on to what we experience anyway so that there is always the sunglasses (my example) between us and what we are trying to experience (e.g., there is no color 'pink' in nature...our mind constructs it, as does it the other colors it experiences). So the question about some ultimate reality becomes what things look like, or sound like or smell like, etc. to some hypothetical God who has no filters and sees things as they really are because he is pure spirit and thus not limited by physical eyes and ears and noses, etc, or that can see everything from all possible directions at once. The answer is that the question is meaningless confabulation....What we cannot experience (be it with our eyes, or through our microscopes, or with our various measuring tools) we cannot experience...end of story. Edited June 26, 2016 by disarray
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