Newtonian Relativity: Galilean Relativity & Beyond

[Russell E]

I'll add to that the fact that even one individual may have held different beliefs and opinions over their own life! So when we quote Newton or Einstein, we don't necessarily know which Newton or which Einstein we are quoting anyway.

Yes, Einstein is a good example of someone whose views were constantly evolving, and he frequently repudiated some of his earlier beliefs. He once said about himself (only half joking) that every year he retracts what he wrote the year before.

Generally speaking, modern textbooks are sufficient--

Sufficient for what? Generally speaking, most students don't need or want to understand the subtleties of the foundations of scientific theories, e.g., the circularities lurking in most naive definitions, and the difficult epistemological issues. So the fact that textbooks do an abysmal job of explaining those things may not be a huge drawback, generally speaking. But what we're talking about here is precisely the foundational issues of a scientific theory, such as the possible meaning and significance of the concept of absolute rest in the context of classical mechanics. I don't think very many textbooks on classical mechanics do a good job of explaining that (nor, to be fair, were they intended to).

In contrast, original works by great thinkers tend to at least pay some attention to the foundational issues, because that's what those thinkers have been wrestling with in the formulation of their theories. But of course, being at the earliest stages, they often have confused and emerging ideas, and often change their minds later, so even the original works of great thinkers can't be taken as definitive statements of that individual's views (as you noted above) - let alone as statements of the truth. Many of the great scientists have been likened to "sleepwalkers" who were guided more by spiritual beliefs, instinct, and intuition than by clear-headed ratiocination.

Needless to say, there IS a vast literature on the foundational issues, but it is in books devoted to the foundations of science, and crackpots hardly ever seem to be acquainted with that literature.

I have seen plenty of crackpots who constantly refer to original texts-- the obscurity in the original language helps them create a kind of smokescreen as to why their crackpot idea is more consistent with the "great mind" than is the modern description of the great theory!

Yes, although in most such cases I think the obscurity is more in the mind of the crackpot than in the original text. For example, Einstein says "for ease of reference, let's call this the stationary frame", and the crackpot says "Aha! Busted!" That's just the dementia of crackpots at work, not an obscurity in the text.

Of course, there ARE genuine obscurities and ambiguities in any text, but crackpots rarely notice those. This thread is a case in point. There are certainly obscurities in Newton's Principia, but on the question of absolute rest Newton was extraordinarily careful to consistently equate "rest" with "uniform motion in a straight line", and he explicitly states the complete relativity of his mechanics. And the fleeting mention of absolute position and velocity in the Scholia is carefully labeled by Newton as purely metaphysical ("the places of absolute space do by no means fall under our senses") and religious ("God constitutes space and time"). In addition, he rather carefully discussed the difficult foundational issues in the Scholia, making the crucial case against relationism with his pail and rotating globes examples. All in all, an incredible intellectual feat - which makes it all the more regretable to have it mis-represented by crackpots.

I'm not really distinguishing "philosophy" from "religion" or "metaphysics", because people tend to apply those words differently depending on which view they personally hold. I'm just distinguishing a scientific theory, which is highly objective and subject to the rules of science, from the contextual interpretation attached to it, which is highly subjective and a function of the cultural milieu in which the theory appears, but not subject to the requirements of scientific demonstrability.

I know metaphysics and religion fall withing the realm of philosophy, but my point is that science does too. Saying that Newton's concept of absolute rest was 'philosophical' doesn't really make the distinction you're trying to make (certainly not to antiquarian crackpots), because objective scientific thinking is philosophical too. Indeed, science in Newton's day was called natural philosophy, and even today the modern dictionary definition of 'philosophy' doesn't exclude "objective" thinking "subject to the rules of science". It's true that some people (especially scientists) use the word 'philosophical' in a limited and (dare I say it?) even slightly perjorative sense to mean "metaphyical" or "subjective" or non-scientific, but that's a specialized meaning that only some people have in their minds. (I recall that Feynman used to delight in referring to the Phil-AH-zofers.) And of course the very distinction between objective and subjective is subject to objective debate within philosophy. So, if your concern is to avoid words that "people tend to apply differently depending on which view they personally hold", I think you should avoid vague and all-inclusive words like 'philosophical' that mean different things to different people, and instead use more precise words like 'metaphysical' and 'religious' to signify (respectively) ideas that have no observable physical significance (does not fall under our senses) or are based on religious beliefs (e.g., the sensorium of God).

 

[Ken G]

In Newton's day the argument about absolute rest was cast in terms of the argument about etherism, i.e., the plenum versus the vacuum, which Newton wrote about elsewhere, but kept it out of the Principia.

The other was that, even if we accept complete Lorentz invariance, it is still possible that one particular foliation is the one inhabited by a universal consciousness (God), just like Newton's "sensorium of God", and so we would be justified in calling that the true foliation -even though we can never know it, since we are not God-like.

Thank you for these additional details. These positions seem to confirm that indeed Newton and Lorentz held philosophical views that they clearly distinguished from the stuff of their scientific theories. That seems like a natural state of affairs, and underscores the importance of distinguishing the theories from the mental pictures that their originators may have used for motivation.

The question of the Vacuum will always be at the center of fundamental conceptions of physical theories - as it has been for thousands of years - but whether we will converge on a single stable conception seems doubtful (to me).

I agree-- I think you and I are in the minority of people who don't view the progress of physics as being toward "the answer", but rather simply a progression of current answers that achieve ever-improving accuracy and generality, but that's it. That seems like a bitter pill for many to swallow, but I can't see what evidence anyone can use to support the former over the latter expectation! How ironic that many scientists seem to choose an unscientific abandonment of reliance on evidence whenever they discuss science itself.

 

[Ken G]

Sufficient for what? Generally speaking, most students don't need or want to understand the subtleties of the foundations of scientific theories, e.g., the circularities lurking in most naive definitions, and the difficult epistemological issues.

By "sufficient", I simply mean sufficient to understand and apply the theories in question, from the perspective of currently most-favored pedagogies. On the topic of epistemology, I have to agree that textbooks make little or no effort to elucidate those issues, nor to trace the historical debates that will likely go on forever, as an interesting kind of "back story" to the progress of physics. Most people just don't seem as interested in that as you and I, so that simply gets left out of the story, but I agree with you that this is something of a shame. Closer contact between physics and the ageless philosophical questions seems to me like a good backdrop against which to better understand the ramifications of the various theories (something that students are generally much weaker at than simply amassing a body of cut-and-dried problems that they know how to solve).

In contrast, original works by great thinkers tend to at least pay some attention to the foundational issues, because that's what those thinkers have been wrestling with in the formulation of their theories. But of course, being at the earliest stages, they often have confused and emerging ideas, and often change their minds later, so even the original works of great thinkers can't be taken as definitive statements of that individual's views (as you noted above) - let alone as statements of the truth. Many of the great scientists have been likened to "sleepwalkers" who were guided more by spiritual beliefs, instinct, and intuition than by clear-headed ratiocination.

I think there is a tendency for thinkers on the frontiers to use philosophy more than do the practitioners in their wake. Of course, the Nobel laureate Steven Weinberg doesn't agree-- he sees philosophical thinking as a kind of useless barrier that must first be removed before you can think scientifically. On the other hand, Weinberg may fall into the standard trap that "my metaphysical thinking isn't philosophy, other people's is."

Yes, although in most such cases I think the obscurity is more in the mind of the crackpot than in the original text. For example, Einstein says "for ease of reference, let's call this the stationary frame", and the crackpot says "Aha! Busted!" That's just the dementia of crackpots at work, not an obscurity in the text.

Yes, the "obscurity" is a moving target-- the language becomes more precise when one is a trained scientist who understands its intent, but for the crackpots, a little knowledge is a dangerous thing!

I know metaphysics and religion fall withing the realm of philosophy, but my point is that science does too. Saying that Newton's concept of absolute rest was 'philosophical' doesn't really make the distinction you're trying to make (certainly not to antiquarian crackpots), because objective scientific thinking is philosophical too.

Yes, the lexicon is tricky here. We can adopt the approach that science is a kind of "arm" of philosophy, created to answer certain types of philosophical questions using particularly well-suited means (which is the meaning you take and is certainly historically accurate). Or, we can adopt an approach that is probably more typical, which is to stress the way science has become a "prodigal son" of philosophy, advancing so far along its own independent path that it is no longer considered to be under the influence of its parent (that's certainly Weinberg's approach, though I feel he goes too far).

I see value in either picture, my intention was merely to stress the "two hats" that people like Newton and Lorentz wore, where at one turn they were describing some scientifically testable theory, and at another they were placing that theory into an essentially sociological context to help them understand what lessons they felt we might wish to take from the theory. The former is objective, the latter largely subjective, and since opinions in science are generally considered to be objective and in philosophy are more subjective, that was the distinction I wished to make.

And of course the very distinction between objective and subjective is subject to objective debate within philosophy. So, if your concern is to avoid words that "people tend to apply differently depending on which view they personally hold", I think you should avoid vague and all-inclusive words like 'philosophical' that mean different things to different people, and instead use more precise words like 'metaphysical' and 'religious' to signify (respectively) ideas that have no observable physical significance (does not fall under our senses) or are based on religious beliefs (e.g., the sensorium of God).

Since I agree with you that it is a shame to treat the term "philosophical" as perjorative in the context of scientific thought, I can see the value in this suggestion. It is a somewhat uphill battle however-- the horse may have already left that barn! Many people think science has so eclipsed its philosophical lineage that it should no longer be thought of as a branch of philosophy, rendering philosophy to the "all other" category. Slipping into that kind of language was like sleeping with the enemy, but that view has rather taken hold I would have to say.