Craig Dilworth

It seems a good time for me to clarify a bit about myself and what I’m up to. I’m 61 years old and have a background in the philosophy of science and human ecology (having published books in both areas), as well as in general philosophy (where I recently completed a 40-year book project). Having said what I have to say in these fields, not too long ago I moved on to another field that has always interested me, and in which I had done some work previously, namely the foundations of physics. My interest in the foundations of physics consists in looking at the subject as a whole, first to understand it, and then, perhaps, to try to improve it. So this means studying electrodynamics, relativity theory, QM and so on, all in a broader perspective in which none of them can be taken for granted. This, of course, is a gigantic undertaking, and if I live long enough to have something to say on the topic, it will undoubtedly be many years from now. This investigation of the foundations of physics has come to include, among many other things, looking at the Doppler effect as it should be conceived on wave as compared to particle theories. In this context, I ran into what seemed to me a problem with regard to the the constancy of the speed of light, and sought help with this problem in Science Forums. Given the equation v = λn, and an instance of light known to be of a constant wavelength but which provides different spectral shifts under different conditions of relative motion, it would appear that the speed of the light ought not be constant. Hm! The first question then becomes: Well, is it constant or isn’t it? If an experiment is to be turned to in this regard, then of course it cannot presuppose either Maxwell’s theory or special relativity, since they both (each in its own way) have the constancy of the velocity of light built into them. And if it turns out that there do exist independent experiments confirming light’s constant velocity, how is it then that that velocity appears to be variable when v = λn is applied to particular instances of the Doppler effect? Is the equation wrong? Or am I making a mistake somewhere here? I’d like to know what’s going on. Note that I’m not making any claims at all! I’m seeking clarification. In this general regard, however, I have much experience of people who thought they were putting me straight when their understanding of the situation turned out to be less sophisticated than my own, and who were just giving knee-jerk reactions to my questioning of the status quo. (Of course any investigation of the foundations of physics must be prepared to question the status quo, even on central points.) This is very tiresome, as you can imagine. To my mind, this sort of reaction is largely what I have experienced in my interactions in Science Forums. This is unfortunate, and I hope it will change!

Well, glad to hear you read it in any case!

Pleased that you accept the vicious circle principle! But it seems to me you have much to learn. You would definitely benefit from reading my Too Smart for Our Own Good!

You'd better check this out. Colour is fcy, not wavelength. Could you please mention for me a few of these expts?

Looking back over my reply, I realise I got off on the wrong foot. I've provided a Darwinian theory of the development of our species, suggesting that according to it we're in for extremely bad times. You reply that times needn't be so bad, but without commenting on the theory. Do you accept the theory but deny the conclusion I draw from it? Or do you disagree with the theory? If the latter, I'd like to know why. And, by the way, it seems to me that common sense suggests this expansion in space business is just science fiction. Please see my reply to Mr Skeptic!

Well, as you use the term, both the special and general relativity theories "contradict" Maxwell; and the special theory "contradicts" the general theory. I don't understand how you can mean that light's having a constant velocity is a theory. Or do you mean the special theory? As I've mentioned elsewhere, all experimental results "supporting" the special theory equally well support the Maxwell-Lorentz theory, with which the special theory is incompatible. I don't believe the special theory has in fact been tested (which tests did you have in mind). The "tests" of the general theory were all second-order and inconclusive, as far as I understand. As I read Otis, that light should have a constant speed relative to its source is quite possible. But its velocity should be affected by the motion of the receiver with respect to it (i.e. to the moving light ray). I don't think SR is based on any facts. As I understand it, it's an attempt to save Maxwell's theory using the Lorentz transformation and at the same time introducing relativity and thereby excluding the ether, which ends up making it incompatible with Maxwell's theory. Which experimental results are you referring to? Great! (Only if it's to refer to me, I've been considering the special theory for more than 30 years ...)

Sorry, this is an ad hominem argument, which doesn't add to the discussion. Otis could be a mystic for all it matters. What you have to do is deal with what he says. And saying "experiment" four times doesn't strengthen your argument. But I'm curious. Which experiments do you have in mind, and do they presuppose a wave theory, or a particle theory, or neither?

When it comes to red- and blue-shift, you have to consider whether it is being understood in terms of a wave or particle theory. On a wave theory, such as Maxwell's, motion of the source is irrelevant. In the case of particle (electrodynamically relativistic) theories, the motion of the source is relevant, but only after the time it takes the radiation to reach the receiver. As I mentioned to Swansont, that the vel. of light should be constant contravenes the general theory of relativity.

Yes, it presents a conundrum. But I'd appreciate your showing how Otis' (and and at least one so-far unmentioned other's) reasoning on this point is mistaken, rather than just referring to "a hundred years of research." Modern physics is a very tricky business, particularly since physicists now seem to accept such things as (Maxwellian, Lorentzian, Hertzian) electrodynamics (your GSP reference), which presupposes the existence of waves in a medium, and at the same time special relativity, which excludes the medium, as well as both the special and general theories of relativity, which are incompatible. By the way, by advocating the constancy of the speed of light you're denying the viability of the general theory of relativity, according to which the speed of light is variable. I think that much of this confusion stems from physicists' inclination to apply either wave or particle thinking whenever convenient (as QM has institutionalised). Your suggestion of re-writing a lot of physics is interesting, since that's precisely what I'm engaged in! As regards the GPS business, of course, logically, the results of Maxwellian electrodynamics could well be right while the theory itself is wrong. Could you please reply to the line of reasoning in my reference to Otis? Thanks! You've got it!

This reply begs the question. In the present context I would benefit most if you directed your comments to the reasoning involved in my Otis reference. Thanks! Could you please meet the line of thinking involved in my reference to Otis? Thanks! (What you present here just side-steps the issue.) Sorry, this isn't an argument, only hand-waving.

The question is whether it is or not. It's not a matter of what either of us say.

No, I should say, fcy and vel are variables; wavelength is not. At least this is what I think I've leared from my study of the subject. Cf e.g Otis (1963), p. 10. The motion of a spectroscope towards or away from a star, caused by the orbital and rotational motions of the earth, cannot in any way affect the ‘wavelength’ (λ) of the light coming from the star. This means that when the motion of the earth causes the spectroscope to approach a star, the shift of the spectrum of the star towards the violet clearly indicates an increase in the frequency (n) of the reception of the constituents of the starlight by the spectroscope. And a red-shift when the spectroscope recedes from the star clearly indicates a decrease in the frequency. “Since velocity equals wavelength multiplied by frequency (v = λn), it follows that when the wavelength of the light coming from a star is unchanged [= the light coming from the star doesn’t change], and its frequency of reception by the spectroscope changes, as indicated by the shift of the spectrum of the light, the velocity (λn) of the light relative to the spectroscope changes.” And it follows further that, more particularly, it is the frequency of the radiation that changes, given that the wavelength of the light emitted is constant, as in the above example. Otis (1963), p. 13. According to the light postulate there is no way by which an observer can detect any difference in the velocity of light relative to him. [so, given the special theory, the postulate that the speed of light is constant cannot be checked?] Nevertheless we see that the shift of the spectrum of light when the spectroscope is moved towards the source provides us with definite empirical evidence that the frequency of reception of the wavefronts by the spectroscope is increased, and hence (l remaining unchanged) the velocity of the light relative to the spectroscope (and relative to the laboratory and observer) is increased, thus contradicting the light postulate.

To start, let's not use c, but v, since c, being a constant, begs the question. Then we get f = v/λ, or, in the notation I'm familiar with, n = v/λ, or v = λn. Thus λ is not, as I'm sure you didn't mean it to be, fcy (colour); n (= f) is fcy (= colour). But then my comments to other contributors should apply.

Of course the velocity of light changes with colour. I don't know where you heard otherwise (since you haven't told me), but it isn't true. If we start with the basic equation v = λn, then with a Doppler effect we get a change in n (fcy/colour), which, given constant λ (wavelength), implies a change in v. Or is v = λn no longer viable?

How can the velocity of light be slower or faster depending on colour (n) and at the same time have a constant vacuum velocity of c? (Answers presupposing special or general relativity not of interest.)