bd-from-kg

Kenny:

I understand. I’m having the same problem on the Sigh. Lewis quote thread.

I understand that. But my point was that it’s highly implausible that the laws of physics would “just happen” to be invariant with respect to coordinate system if this did not reflect the fundamental nature of things in some way. If there were a “privileged reference frame”, metaphysical or otherwise, it would be natural that the laws of physics would look simpler in this frame than in other ones. There would certainly be no reason to expect them to look the same in all frames.

This is precisely why the concept of the “ether” was eventually abandoned. Even though the “ether” was postulated to be undetectable in itself, it defined a “privileged” reference frame – namely the one in which the ether was at rest. But if there were such a frame, physicists reasoned, it should be possible to distinguish it from “unprivileged” frames by means of some experiment. When it became clear that there was no experimental way to distinguish the supposedly privileged frame from any other inertial frame, the concept of “ether” – and with it the concept of a “privileged frame” - was abandoned. The theory you describe proposes to reintroduce it for no apparent reason – or rather, for metaphysical reasons. This is completely antiscientific.

In science one does not propose a more complicated conceptual framework that has no practical advantage whatever over the “standard” one merely because one likes the supposed metaphysical implications. If philosophers want to speculate about the metaphysical implications of the best theory, they’re welcome to, but this cannot be allowed to drive (or even to influence) the selection of a theory from those that “fit the facts”. This must be done strictly in accordance with Ockham’s Razor.

Also, as I pointed out in my last post, the fact that matter can be converted into energy in accordance with the equation E = mc² seems to show pretty definitively that the equations of GR are not merely a set of instructions for converting measurements in one reference frame to another one. In special relativity this point of view is still plausible; the equation merely indicates that the apparent mass of a moving object (in one frame) appears as kinetic energy in another. But general relativity blows this viewpoint to smithereens; it’s no longer possible to regard the equation in this way. We find that the effects described by the equations are real and not merely disguised descriptions of the different way things “look” in different reference frames.

Ordinarily when one says that a measuring device’s reading are being “distorted” by something, the implication is that there’s a “fix” or a better design that would allow it to yield “true” readings. But that’s not the case here. Any measuring device imaginable would give these same readings unless it’s malfunctioning. Under these conditions it seems meaningless to say that the readings are “wrong” in some sense. How can one distinguish between the hypothesis that the readings are “correct” – in this case, that they’re recording actual time – and the hypothesis that what they’re recording is some sort of “quasi-time”, such that the “real” time could only be measured by some sort of nonexistent “metaphysically privileged” clock? It seems to me that the hypothesis that there is some inaccessible “time” which cannot be measured, even in principle, by any device, and which has no effect whatsoever on anything, is not only not a scientific hypothesis, but isn’t a meaningful hypothesis at all.

Suppose that someone were to propose that a beach ball which appears to be red, and which all measurements indicate reflects only light at wavelengths in the “red” part of the spectrum, is “really” blue. And what if he says that this “blueness” cannot be detected, even in principle, in any imaginable way? What would you make of this? Would you regard this as a serious hypothesis, or even a meaningful one?

Whereas I think that it would be a terrible mistake for a theory about the “real world” to attempt to “take into account” our “qualitative” (read “subjective”) experience at all. This is directly contrary to the whole purpose and function of science. Of course, you could say that this theory isn’t about the real world, but about some sort of “metaphysical reality”, and is therefore outside the domain of science. But in that case I’m at a loss as to why it bothers to talk about things like “privileged frames” and “distorted measurements”. If one is making up a theory that doesn’t even purport to be about the real world, why not let the imagination run completely free, unconstrained by any thought of relating it to the physical world at all?

Subjective experience does not provide access to “metaphysical realities”. It provides some evidence as to what’s going on in one’s brain.

Amen. This sort of thing is not properly “accounted for” by metaphysical theories, but by theories about how the brain is structured to organize and interpret sensory data. If you have a perfectly satisfactory physical theory that doesn’t seem to correspond to our “intuitions”, so much the worse for our intuitions; we’ll just have to learn to think about the world in a different way.

Anyway, we’re getting pretty far afield from the original question, so you’re probably right that it’s time to stop.