Measurement as Criterion for Positive Ontological Status

[ydoaPs]

ajb inspired me to create a thread about the nature of measurement, but the same quote inspired this thread.

 

My philosophy is quite pragmatic here: 'real' things are what I can measure.

As far as measurement as a criterion for ontological reality, I'm even less sure. We can measure energy, but it's not clear that energy exists. Many people are hesitant to give positive ontological status to things which are frame dependent. But energy isn't just frame dependent in that my energy count is different from your energy count. Energy is co-ordinate dependent such that my energy count is different depending on how I count. Wile E Coyote on a cliff is an example. If I count the cliff level as y=0, then Mr Coyote has no gravitational potential energy. If I count the level of the valley as y=0, then he has a bunch. But both of those energies are from the same frame. That's really weird for something that's real.

[moth]

How about: if i can measure it, it represents something real.

temperature is real in the sense that it's caused by mass and motion.

same for mr. coyote, the potential energy represents mass in a "field";

sorry for being dumb. just hoping to get the ball rolling.

Edited November 12, 2015 by moth

[Reg Prescott]

Great idea for a thread, ydoaPs! I thoroughly enjoyed your reading your lengthy and well considered remarks in your "sister" thread, and look forward to watching it develop. I've had the pleasure of discussing certain topics with ajb since joining the site, and almost responded to his quote above myself, wondering if he's prepared to accept (what I take as) the counterintuitive implications of his own philosophy. I hope you won't mind me adding a few remarks here.

 

Firstly, in a recent thread of my own, I was quite fascinated to discover the prevalence of antirealist sentiment among our members. The contributing members were almost all physicists, as far as I can tell, a domain where the kind of verificationist ontology, influenced by positivist philosophy, and by extension, the Copenhagen interpretation of quantum mechanics, does indeed hold sway. Those members, however, seemed committed to the view that all of science is like that; a claim I find implausible, but quite willing to be proven wrong. I'd be very surprised if, say, geologists or evolutionary biologists, endorse the same philosophy, viz., that the only reality is that of the observational consequences of their models, and that quarks et al (assuming they are unobservable) are therefore not real, or else the question of their reality is moot.. Surely few, if any, geologists hold that unobservable theoretical entities such as tectonic plates (if they indeed are considered to be such entities) should be denied bona fide ontological standing.

 

Secondly, I'd like to put the question to ajb: Your philosophy seems to imply there are no verification-transcendent truths. That is to say, only that which can be verified or measured can be considered real, and statements regarding that which is unmeasurable or unverifiable are indeterminate -- they have no truth value. If we can't know about something, or at least garner certain evidence to bear upon it one way or the other, then it's not real.

 

Take a standard philosophers' example such as the question of what Napoleon ate for breakfast before getting his hands dirty (one of them anyway) at Waterloo. Presumably this question transcends any possible means of verification or measurement. Would you then hold, ajb, as I believe your philosophy implies, that the question has no answer?

[Strange]

Firstly, in a recent thread of my own, I was quite fascinated to discover the prevalence of antirealist sentiment among our members. The contributing members were almost all physicists, as far as I can tell, a domain where the kind of verificationist ontology, influenced by positivist philosophy, and by extension, the Copenhagen interpretation of quantum mechanics, does indeed hold sway. Those members, however, seemed committed to the view that all of science is like that; a claim I find implausible, but quite willing to be proven wrong. I'd be very surprised if, say, geologists or evolutionary biologists, endorse the same philosophy, viz., that the only reality is that of the observational consequences of their models, and that quarks et al (assuming they are unobservable) are therefore not real, or else the question of their reality is moot.. Surely few, if any, geologists hold that unobservable theoretical entities such as tectonic plates (if they indeed are considered to be such entities) should be denied bona fide ontological standing.

 

There is a problem deciding where we stop thinking of our observations (measurements) and conclusions as "models" and when they become descriptions of "reality".

 

Common sense tells us that the subjects of geology (whether a grain of sand or a mountain) are real while the status of electrons and, even more so, quarks is less clear. But I'm not sure that common sense view can be rationally defended. For example, how can "real" things (a grain of sand) be made of things which may not exist (quarks).

 

And when it comes to things like the internal structure of the Earth and even plate tectonics, we only have indirect evidence. So does the Earth really have a solid iron core surrounded by a liquid outer core? Or is that just a model?

 

And how can we sure that the way we perceive a mountain represents reality; all we have to compare it against is our own perceptions. Even "objective" measurements confirmed by others are only available via our perceptions (hearing or reading their results). So we don't have any direct access to reality; we only have our measurements (taking that to include informal observations, such as looking at things).

 

I am a naive realist: I believe that when we see a chair or a mountain, or even data suggesting the existence of quarks, then that is what the world is really like. But I also know that this position is as logically unsupportable as arguments for (or against) solipsism.

 

(And, just as an aside, "Those members, however, seemed committed to the view that all of science is like that" was a strawman created by SB.)

 

Presumably this question transcends any possible means of verification or measurement. Would you then hold, ajb, as I believe your philosophy implies, that the question has no answer?

 

Interesting question. There seem to be two meanings to "having no answer". One is cases like this where the "facts" exist (he did have something, or maybe nothing, for breakfast) but not accessible to us. The other case is where the answer doesn't exist (the question has no meaning), such as "which path did an individual photon take".

[Ophiolite]

Disconnected points:

 

No one appears to have defined real, thus far. I would have thought that a suitable starting point.

 

In its first century geology was almost devoid of measurements, and it did quite well.

 

Potential energy is a relative thing and so the OP's concerns on this matter may be set aside as semantics, not science.

 

Since I don't know of any way to determine if any of this is real I just use the working assumption that it is.

 

Full circle: when one does attempt to define real one realises it can be as inclusive or exclusive as one wishes and hence is - in my view - not really worth worrying about.

[Strange]

No one appears to have defined real, thus far. I would have thought that a suitable starting point.

 

Isn't that what the quoted bit from ajb does? (Attempts to do?)

 

 

Full circle: when one does attempt to define real one realises it can be as inclusive or exclusive as one wishes and hence is - in my view - not really worth worrying about.

 

I agree that nearly all such questions really centre on the meaning of the word "real" (or "exist", etc.) - and there are several live threads on this at the moment, with regard to various things, from numbers and the quantum wave equation, to scientific theories in general.

 

It is worth worrying about when the two (or more) sides in a discussion have different assumptions about what it means and so may be in violent agreement.

[Ophiolite]

Isn't that (defining real) what the quoted bit from ajb does? (Attempts to do?)

Yes, you are quite right. I think I overlooked it because I don't find it to be a convincing definition. Whatever definition of real I might have on a particular day it would not insist on measurement, though it might like potential observation.

[MonDie]

ajb inspired me to create a thread about the nature of measurement, but the same quote inspired this thread.As far as measurement as a criterion for ontological reality, I'm even less sure. We can measure energy, but it's not clear that energy exists. Many people are hesitant to give positive ontological status to things which are frame dependent. But energy isn't just frame dependent in that my energy count is different from your energy count. Energy is co-ordinate dependent such that my energy count is different depending on how I count. Wile E Coyote on a cliff is an example. If I count the cliff level as y=0, then Mr Coyote has no gravitational potential energy. If I count the level of the valley as y=0, then he has a bunch. But both of those energies are from the same frame. That's really weird for something that's real.

Is 0 meaningful in this instance? In Kelvins (ratio level), 0 indicates no heat. In Celcius (interval level), 0 is arbitrary. Would it make sense to speak of Wile Coyote as having negative potential energy, sort of like below zero Celcius?

Perhaps a proper 0 would be the center of the earth.

[Strange]

Perhaps a proper 0 would be the center of the earth.

 

But that introduces the problem of potential energy on the Moon or Mars. So, conventionally, 0 is taken to be an infinite distance away (hence gravitational potential energy is negative).

 

But we are getting off topic...

[MonDie]

 

But that introduces the problem of potential energy on the Moon or Mars. So, conventionally, 0 is taken to be an infinite distance away (hence gravitational potential energy is negative).

 

But we are getting off topic...

The pull of the moon is distinct from the pull of Earth. Anyway, ydoaPs thinks PE is relative, but can't I obtain an absolute measure of Coyote's PE by placing a scale beneath him? Suppose Earth is falling into the Sun with Coyote at midnight. My scale won't read Coyote's fall toward the Sun because that's kinetic energy. If my scale has wings to keep Coyote afloat, then my scale exerts a force as it raises him, causing it to give a higher reading as Coyote's kinetic is converted into potential. One way to avoid this is to place the scale beneath the lift, but then I'm measuring Coyote and his lift, not just Coyote.

Edited November 13, 2015 by MonDie

[ydoaPs]

Anyway, ydoaPs thinks PE is relative, but can't I obtain an absolute measure of Coyote's PE by placing a scale beneath him?

No, you can't.

[MonDie]

Alas, Earth is always falling into the Sun.

[MonDie]

No, you can't.

Dang it you're right. As he rises, he'll have more PE but less weight. *embarrassed*

 

If it can't be measured directly, then why is it your example? If something can be measured directly and your measurement is reliable, then the value will be absolute.

How about heat? I suppose I might get a different reading if I move the thermometer quickly enough through its substrate (because heat is kinetic energy?). This is only because I've changed my measurement, but it does challenge whether heat (or temperature) is an absolute property of the substrate.

Edited November 14, 2015 by MonDie

[moth]

can we say "real" means some impetus that has an effect in the objective universe. objective meaning available to anyone who makes the relevant observations.
or is there a contradiction lurking? like is the motivating force "real"?
hope you'll forgive me for being a blind man in the dark here.

[andrewcellini]

If it can't be measured directly, then why is it your example? If something can be measured directly and your measurement is reliable, then the value will be absolute.

there is no preferred or absolute frame of reference, and there's nothing stopping you from analyzing the system where y = 0 other than it's kind of asinine and not as intuitive. the end of the motion wile's at y = -h or y = h depending on what signs you want to use which affects the sign of the potential energy.

Edited November 13, 2015 by andrewcellini

[ydoaPs]

If it can't be measured directly, then why is it your example?

Nothing can be measured directly.

[andrewcellini]

Nothing can be measured directly.

what about length? or is that still interpreted through theory?

[MonDie]

what about length? or is that still interpreted through theory?

You must assume that your reference for length won't contract or expand, so again there are assumptions involved.

 

However, a coherentist might say that it is corroboration from various measurements that exalts a claim.

Edited November 14, 2015 by MonDie

[andrewcellini]

You must assume that your reference for length won't contract or expand, so again there are assumptions involved.

sure

 

also measured lengths are frame dependent, which slipped my mind

Edited November 14, 2015 by andrewcellini

[cladking]

there is no preferred or absolute frame of reference, and there's nothing stopping you from analyzing the system where y = 0 other than it's kind of asinine and not as intuitive. the end of the motion wile's at y = -h or y = h depending on what signs you want to use which affects the sign of the potential energy.

 

 

Indeed.

 

The important thing in calculation is to maintain the same frame of reference.

 

The important thing for Wile E Coyote is to not know there's no longer a cliff under him since there's no acceleration until he does. Fortunately for Acme it requires only a frame or two for even fatal injuries to completely heal.