The Logical Leap: Induction in Physics

[George H. Smith]

Suppose every existent in the universe, whether in the form of matter or energy, were to disappear. What would be left? By the terms of this hypothetical, we would have to say "nothing." Another way of putting this, for many people, would be to say, "Only empty space would remain."

I would call *that* careless use of language, equating "nothing" with "empty space," as if "space" is being thought of as a container into which stuff is put. If there's "nothing," there isn't "space" either.

"Space" in "space-time" is thought of as a something, an existent, not merely a measurement of relationships between existents.

If you say that space is an existent, and if I want to verify that space really does exist and is not merely a figment of your imagination, what attributes should I look for? And where should I look?

Will I be looking for one gigantic existent, or are there many different spaces? Is space stationary, or can it move around? Is space composed of something, such as matter or energy? Or is it sui generis?

Ghs: Physicists, like everyone else, are obliged to make sense when they use conventional language. They are not the high priests of the modern world with a privileged knowledge of "ultimate reality" that exempts them from the responsibility of speaking intelligibly when explaining their results to laypersons.

ES: Is the obligation like a categorical imperative? Are physicists permitted to use "mass" with a technical meaning which isn't the conventional meaning? "Energy"? "Weight"? Etc. Probably almost all, if not all, the terms used in physics are also used with different meanings in common parlance. And it's not as if there aren't sources where laypersons can find explanations of the physics meaning of terminology. The meanings aren't being hidden as if by a priesthood keeping secrets.

Ellen

The obligation to speak intelligibly is more like a hypothetical imperative, to wit: Physicists should pay attention to the meaning of words if they don't want to utter gibberish.

I have no problem if physicists assign different meanings to common words, so long as they are clear that this is what they are doing. And if they are clear about this, then they will need to exercise extreme caution when announcing their conclusions to a lay audience, making grand pronouncements to the effect that physics has shown that our commonsense notions about "space" and "time" are wrong. (Claims like this have been made on OL.) Physics has shown no such thing, if the words "space" and "time" mean something different to a physicist than they do to a layperson. These two groups are talking about different things.

It is not my intention to denigrate physics; far from it. My problem is with those physicists, or those people who claim to know something about physics, who draw unwarranted conclusions -- many of them philosophical -- from the findings of physics.

My point about high priests had nothing to do with secrets. Rather, I simply wished to emphasize what I have stated before, viz., that when physicists leave their area of expertise, they are bound by the same canons of intelligibility that apply to everyone else. A physicist, however brilliant, does not have a special epistemological warrant to speak nonsense and then, when a layperson points out that he is speaking nonsense, flash his scientific credentials, while claiming that nonspecialists cannot understand the profundity of his statements.

If a physicist believes that he cannot adequately express his conclusions in conventional language, because they would make no sense, then he should candidly admit this. In this case we would be confronted with one of two possibilities: either the mysteries of physics are inexpressible (rather like the Trinity and other "truths" of theology), or the physicist has not learned how to express himself intelligibly. I would always wager on the latter possibility.

Ghs

[James Heaps-Nelson]

Suppose every existent in the universe, whether in the form of matter or energy, were to disappear. What would be left? By the terms of this hypothetical, we would have to say "nothing." Another way of putting this, for many people, would be to say, "Only empty space would remain."

I would call *that* careless use of language, equating "nothing" with "empty space," as if "space" is being thought of as a container into which stuff is put. If there's "nothing," there isn't "space" either.

"Space" in "space-time" is thought of as a something, an existent, not merely a measurement of relationships between existents.

If you say that space is an existent, and if I want to verify that space really does exist and is not merely a figment of your imagination, what attributes should I look for? And where should I look?

Will I be looking for one gigantic existent, or are there many different spaces? Is space stationary, or can it move around? Is space composed of something, such as matter or energy? Or is it sui generis?

Ghs: Physicists, like everyone else, are obliged to make sense when they use conventional language. They are not the high priests of the modern world with a privileged knowledge of "ultimate reality" that exempts them from the responsibility of speaking intelligibly when explaining their results to laypersons.

ES: Is the obligation like a categorical imperative? Are physicists permitted to use "mass" with a technical meaning which isn't the conventional meaning? "Energy"? "Weight"? Etc. Probably almost all, if not all, the terms used in physics are also used with different meanings in common parlance. And it's not as if there aren't sources where laypersons can find explanations of the physics meaning of terminology. The meanings aren't being hidden as if by a priesthood keeping secrets.

Ellen

The obligation to speak intelligibly is more like a hypothetical imperative, to wit: Physicists should pay attention to the meaning of words if they don't want to utter gibberish.

I have no problem if physicists assign different meanings to common words, so long as they are clear that this is what they are doing. And if they are clear about this, then they will need to exercise extreme caution when announcing their conclusions to a lay audience, making grand pronouncements to the effect that physics has shown that our commonsense notions about "space" and "time" are wrong. (Claims like this have been made on OL.) Physics has shown no such thing, if the words "space" and "time" mean something different to a physicist than they do to a layperson. These two groups are talking about different things.

It is not my intention to denigrate physics; far from it. My problem is with those physicists, or those people who claim to know something about physics, who draw unwarranted conclusions -- many of them philosophical -- from the findings of physics.

My point about high priests had nothing to do with secrets. Rather, I simply wished to emphasize what I have stated before, viz., that when physicists leave their area of expertise, they are bound by the same canons of intelligibility that apply to everyone else. A physicist, however brilliant, does not have a special epistemological warrant to speak nonsense and then, when a layperson points out that he is speaking nonsense, flash his scientific credentials, while claiming that nonspecialists cannot understand the profundity of his statements.

If a physicist believes that he cannot adequately express his conclusions in conventional language, because they would make no sense, then he should candidly admit this. In this case we would be confronted with one of two possibilities: either the mysteries of physics are inexpressible (rather like the Trinity and other "truths" of theology), or the physicist has not learned how to express himself intelligibly. I would always wager on the latter possibility.

Ghs

George, I disagree with this. The reason we have physicists and popularizers who spout nonsense is that the public pays more for nonsense. The public will pay more for the Dancing Wu Li Masters than a book by Sheldon Glashow or Albert Einstein. Spacetime is a construct to describe how dimensions and times are variable with respect to velocities and mass/energy densities. The reason this construct is unfamiliar to the public is not that the best physicists are, on average,explaining it poorly, it's that the public has no contextual experience of it. The reason most people aren't able to conceive of length contraction, time dilation and the curvature of a four-dimensional representation of space and time variance on mass/energy density is that we have a local rather than universal context. The only way to get a universal context is go into a laboratory and measure extreme and disparate conditions or collect reports from the laboratory. It is much easier to do folk physics and let ourselves be fooled because that's the evolutionary default.

It isn't that our commonsense notions of space and time are wrong, it's that they are local and not universal.

When Euler made his ridiculous statement, he left the realm of mathematics and entered the realm of spirituality. Given that his world was mostly mathematics, it's not surprising that he found his spirituality there. No doubt that was something he couldn't communicate.

Jim

Edited July 29, 2010 by James Heaps-Nelson

[9thdoctor]

When Euler made his ridiculous statement, he left the realm of mathematics and entered the realm of spirituality.

According to Wikipedia the Euler/Diderot story is apocryphal (see near the bottom of the page).

[James Heaps-Nelson]

When Euler made his ridiculous statement, he left the realm of mathematics and entered the realm of spirituality.

According to Wikipedia the Euler/Diderot story is apocryphal (see near the bottom of the page).

Thanks, I was taking George's statement at face value. In any case, the apocryphal story does encapsulate the point he was trying to make.

Jim

[BaalChatzaf]

Just a word on that story about Euler in Queen Catherine's court: It was probably just a story, but even if true, Euler was busting Diderot's chops. Diderot was a mathematical ignoramus and Euler was ragging on him. Euler was never a mystic, at least not a mystic to the extent Newton was. In addition Euler was one of the ten best mathematicians of all time since the beginning of the world. Also consider, that in Euler's time all the intellectuals with few exceptions (for example Diderot - who was an atheist) were believers to one degree or another. Science has not progressed far enough to completely discredit the idea of God, god or the gods. That did not happen until the 19th century. Most people prior to the very late 18th century (when certain geological discoveries were made) believed the Earth was only a few thousand years old and that man was created specially by God. Evolution did not catch on until the 19th century.

Ba'al Chatzaf

[merjet]

If n = 0, the left side becomes undefined. Looks good to me!

[Brant Gaede]

Suppose every existent in the universe, whether in the form of matter or energy, were to disappear. What would be left? By the terms of this hypothetical, we would have to say "nothing." Another way of putting this, for many people, would be to say, "Only empty space would remain."

I would call *that* careless use of language, equating "nothing" with "empty space," as if "space" is being thought of as a container into which stuff is put. If there's "nothing," there isn't "space" either.

"Space" in "space-time" is thought of as a something, an existent, not merely a measurement of relationships between existents.

If you say that space is an existent, and if I want to verify that space really does exist and is not merely a figment of your imagination, what attributes should I look for? And where should I look?

Will I be looking for one gigantic existent, or are there many different spaces? Is space stationary, or can it move around? Is space composed of something, such as matter or energy? Or is it sui generis?

Ghs: Physicists, like everyone else, are obliged to make sense when they use conventional language. They are not the high priests of the modern world with a privileged knowledge of "ultimate reality" that exempts them from the responsibility of speaking intelligibly when explaining their results to laypersons.

ES: Is the obligation like a categorical imperative? Are physicists permitted to use "mass" with a technical meaning which isn't the conventional meaning? "Energy"? "Weight"? Etc. Probably almost all, if not all, the terms used in physics are also used with different meanings in common parlance. And it's not as if there aren't sources where laypersons can find explanations of the physics meaning of terminology. The meanings aren't being hidden as if by a priesthood keeping secrets.

Ellen

The obligation to speak intelligibly is more like a hypothetical imperative, to wit: Physicists should pay attention to the meaning of words if they don't want to utter gibberish.

I have no problem if physicists assign different meanings to common words, so long as they are clear that this is what they are doing. And if they are clear about this, then they will need to exercise extreme caution when announcing their conclusions to a lay audience, making grand pronouncements to the effect that physics has shown that our commonsense notions about "space" and "time" are wrong. (Claims like this have been made on OL.) Physics has shown no such thing, if the words "space" and "time" mean something different to a physicist than they do to a layperson. These two groups are talking about different things.

It is not my intention to denigrate physics; far from it. My problem is with those physicists, or those people who claim to know something about physics, who draw unwarranted conclusions -- many of them philosophical -- from the findings of physics.

My point about high priests had nothing to do with secrets. Rather, I simply wished to emphasize what I have stated before, viz., that when physicists leave their area of expertise, they are bound by the same canons of intelligibility that apply to everyone else. A physicist, however brilliant, does not have a special epistemological warrant to speak nonsense and then, when a layperson points out that he is speaking nonsense, flash his scientific credentials, while claiming that nonspecialists cannot understand the profundity of his statements.

If a physicist believes that he cannot adequately express his conclusions in conventional language, because they would make no sense, then he should candidly admit this. In this case we would be confronted with one of two possibilities: either the mysteries of physics are inexpressible (rather like the Trinity and other "truths" of theology), or the physicist has not learned how to express himself intelligibly. I would always wager on the latter possibility.

Ghs

George, I disagree with this. The reason we have physicists and popularizers who spout nonsense is that the public pays more for nonsense. The public will pay more for the Dancing Wu Li Masters than a book by Sheldon Glashow or Albert Einstein. Spacetime is a construct to describe how dimensions and times are variable with respect to velocities and mass/energy densities. The reason this construct is unfamiliar to the public is not that the best physicists are, on average,explaining it poorly, it's that the public has no contextual experience of it. The reason most people aren't able to conceive of length contraction, time dilation and the curvature of a four-dimensional representation of space and time variance on mass/energy density is that we have a local rather than universal context. The only way to get a universal context is go into a laboratory and measure extreme and disparate conditions or collect reports from the laboratory. It is much easier to do folk physics and let ourselves be fooled because that's the evolutionary default.

It isn't that our commonsense notions of space and time are wrong, it's that they are local and not universal.

When Euler made his ridiculous statement, he left the realm of mathematics and entered the realm of spirituality. Given that his world was mostly mathematics, it's not surprising that he found his spirituality there. No doubt that was something he couldn't communicate.

Jim

Why not just refer to the speed of light as "the cosmological constant" thus getting rid of all that relativity stuff?

--Brant

[George H. Smith]

Spacetime is a construct to describe how dimensions and times are variable with respect to velocities and mass/energy densities.

This is my understanding as well. My problem is whether the theoretical construct known as space-time should be described as an "existent." This strikes me as the reification of an abstraction.

Ghs

[merjet]

Why not just refer to the speed of light as "the cosmological constant" thus getting rid of all that relativity stuff?

Lesson #2. Why not just refer to the post # and avoid wasting space and others' time scrolling?

[Brant Gaede]

Why not just refer to the speed of light as "the cosmological constant" thus getting rid of all that relativity stuff?

Lesson #2. Why not just refer to the post # and avoid wasting space and others' time scrolling?

Lesson #3. The only people who need to scroll are those who haven't been reading this thread.

--Brant

Edited July 29, 2010 by Brant Gaede

[James Heaps-Nelson]

Spacetime is a construct to describe how dimensions and times are variable with respect to velocities and mass/energy densities.

This is my understanding as well. My problem is whether the theoretical construct known as space-time should be described as an "existent." This strikes me as the reification of an abstraction.

Ghs

That's an open question. In order to answer it, we would have to have direct physical evidence of how the gravitational force is mediated. As mentioned by Dragonfly earlier in the thread, there is compelling indirect evidence from the Hulse-Taylor binary star system. Scientists are trying to detect gravity waves to confirm it.

Jim

[merjet]

Lesson #3. The only people who need to scroll are those who haven't been reading this thread.

Lesson #3a. Not true if I click to see a long post while on the Today's Active Topics page. Doing so navigates to the top of the post. If the post is long enough, I need to scroll down to see the latest reply.

[Brant Gaede]

Lesson #3. The only people who need to scroll are those who haven't been reading this thread.

Lesson #3a. Not true if I click to see a long post while on the Today's Active Topics page. Doing so navigates to the top of the post. If the post is long enough, I need to scroll down to see the latest reply.

I'm sorry; I wasn't sensitive to that.

--Brant

[merjet]

Brant, apology accepted. Also, I use a large monitor (11.4 x 20 in.) most of time. Imagine somebody using a smart-phone.

[Brant Gaede]

Brant, apology accepted. Also, I use a large monitor (11.4 x 20 in.) most of time. Imagine somebody using a smart-phone.

It's not smart to use a smart phone: DO YOU HEAR ME USERS!!?? (envy)

--Brant

[Robert Campbell]

There's a really meaty reader review of the Harriman book at amazon now, by one Travis Norsen:

http://www.amazon.co...=cm_cr_rdp_perm

In this extended passage, Norsen makes a number of key points:

Let me now, more briefly, indicate some further problems I see with the book. In contrast to the three points raised and discussed in detail above, which I see as fundamental by the standards of the overall structure and purpose of the book itself, the following are in various ways more marginal (though still sufficiently important to warrant mentioning).

First, there is a recurring ambiguity between two very different senses in which a concept or other idea can be said to be "invalid." That is: some concepts (e.g., "angel") are invalid in the sense that their very formation rests on something irrational such that they in fact never should have been formed in the first place. But others (e.g., at least arguably, "impetus" and "phlogiston") are invalid in the sense that they turn out to involve classification by non-essentials or to refer to hypothesized entities or substances which turn out in fact not to exist. Such concepts can be said to be invalid from the point of view of our present, more sophisticated context of knowledge, but were -- despite this -- perfectly rational to form (at least with some hypothetical status) in the earlier, more primitive context. But in claiming that invalid concepts are "red lights" to induction -- a central thesis of the book -- it is clearly important to distinguish these two senses of "invalid." The point of trying to construct a theory of induction, after all, is to help us -- in the present -- become better inducers. And it is obviously vacuous to advise somebody to base inductive generalizations only on those concepts which it is not only rational to have formed, but which -- in addition -- will turn out to remain "valid" in the presently-unknowable context of future centuries.

Speaking more generally, the complaint about the book here is that sometimes the history suffers from an element of Whiggishness -- i.e., using the benefit of hindsight from our contemporary perspective to present a story of good guys doing exclusively rational things and thereby discovering truths which stand the test of time, and bad guys doing exclusively irrational things and thereby arriving only at falsehoods. One example of many that could be given is Harriman's account of the debates over assigning relative atomic weights to the chemical elements. He dismisses Dalton's scheme for assigning atomic weights as based merely on "simplicity" arguments, and praises Avogadro's alternative scheme as leading to "unambiguous" results. (page 162) But in fact both schemes were argued for on the basis of "simplicity" -- just applied to different sets of phenomena -- and both led to atomic weight assignments that were relatively unambiguous. Of course, we know, today, that Avogadro's scheme leads to the *correct* atomic weights. But nobody at the time, Avogadro himself certainly included, was in a position to know this. (That is why these particular debates existed, and why Avogadro's hypothesis was for several decades regarded as hypothetical.) Anyway, this sort of bias sometimes renders Harriman's accounts bad as history -- and bad in a way that matters in the context of the role that the history is supposed to be playing in this book.

A second marginal problem I see with the book is a kind of sustained confusion about the relationship between causality and math in physics. Harriman stresses that "it is by means of relating quantities that scientists grasp and express causal relationships" (page 84), lobbies for the relative importance of the quantitative over the qualitative (page 181), and indeed suggests that physics should be understood as (merely?) the process of re-introducing measurements that were omitted in the process of originally-forming the involved concepts (page 231-2). All of this strikes me as very floaty and rationalistic (and also inconsistent!), and it just profoundly fails to resonate with my own understanding of how physicists unravel causal connections and formulate mathematical laws. Some examples will have to suffice to indicate my discomfort here. Thus: Max Planck famously stumbled on the correct formula for the spectral intensity of blackbody radiation, but (by his own explicit and indeed impassioned admission) did so without knowing what it meant physically or causally; it was only subsequently that Einstein suggested the particulate-character of electromagnetic radiation as the relevant causal/physical meaning of the formula -- a chronology that strikes me as rather typical in the history of physics. And: it seems to me, contrary to Harriman's explicit statement on page 112, that astronomers *did* precisely "begin by grasping the structure of the solar system in some rough, qualitative way [Copernicus!] and then use mathematics merely to fill in the quantitative details [Kepler!]" -- just as Faraday first grasped in a qualitative way that electromagnetic phenomena should be understood in terms of continuous *fields* before Maxwell could discover his eponymous equations, and just as de Broglie's suggestion that electrons were (qualitatively) wave-like preceded Schroedinger's discovery of the appropriate (quantitative) wave equation. Thus, I see important causal relationships being discovered in a purely qualitative form, equations being put forward in the absence of any relevant causal understanding, and (therefore also) equations that do *not* represent the re-introduction of quantitative measurements to already-grasped causal connections. I will also just note here in passing that almost everything in Chapter 7 about the role of math in physics and the reasons for its not playing that same role in philosophy, strike me as incomprehensibly rationalistic and fundamentally misguided.

A third "marginal" issue pertains to a question of the domain of applicability or scope of inductive generalizations -- mathematical laws in physics in particular. Unlike some issues mentioned earlier, this issue does actually get addressed at several places in the book. It comes up, for example, with Galileo's "discovery" that the period of a simple pendulum is independent of amplitude (or more precisely would be in the absence of air resistance -- or so Galileo thought), and also with the question (already mentioned) of whether Kepler was entitled, having shown that Mars moves in an ellipse, to infer that *all* planets move in ellipses. On both of these examples, I see problematic inconsistencies in the text. But let us focus here on a kind of paradigm example for the kind of issue I'm worried about: Newton's inverse square law of universal gravitation. Harriman is adamant that "Newton's laws are not contradicted by Einstein's discovery of relativity theory" (page 20). He repeats again later that "Newton's laws have not been contradicted by any discoveries made since the publication of the Principia" (page 146). Yet it is known that, for example, Newton's inverse square law makes predictions for the orbit of Mercury that are inconsistent with its actual orbit. How does Harriman propose to reconcile the relevant facts here?

This is not too clear. For example, Harriman asserts that "Newton ... *never* said, 'My laws apply without modification not only to all that is currently known in physics and astronomy...'." (page 146) That is certainly true. But the question is: what *should* he have said? That is -- granted Newton was entitled to infer an inverse-square gravitational force that applied not just to the particular objects he had studied, but one that was in some sense *universal* -- what, precisely, is the relevant sense of "universal"? Was there, for example, some range of distances over which he was in a position to assert the universal applicability of the inverse square law? (At least for objects whose masses lie in a certain range, perhaps? And/or to a certain degree of accuracy, perhaps?) Such questions are nowhere answered, which leaves one wondering if the only universality Newton was entitled to assert was the vacuous: this will apply wherever it does, in fact, turn out to apply. Harriman does suggest an alternative -- but very dubious -- answer in Chapter 1, where he asserts that "Newton's science remains absolute within Newton's context." Here Harriman's intended meaning is unclear. If this means that Newton was entitled to believe only that his laws were true in the domain of situations he had studied (an interpretation that is perhaps supported by Harriman's comments on Galileo's theory of projectiles on page 190), then one must address the kinds of questions I was just raising: what *is* this domain, exactly, and why was Newton (in his context of knowledge) entitled to generalize within it (but not outside it)? But if Harriman's remark means instead that Newton's laws were -- and remain -- "true for Newton" in the sense that Newton, due to his relatively limited context of knowledge, didn't know about the kinds of situations where those laws fail to apply, I would regard that as a profoundly wrong and indeed a profoundly misguided defense of the expansive/cumulative/hierarchical character of knowledge.

Again, on this kind of issue, I find that where Harriman should take advantage of the opportunity to shed light on an important and admittedly difficult set of issues, he instead retreats to vague (but also vaguely Objectivist-sounding) slogans, and windy assertions (one might call them arguments from intimidation) like that which concludes Chapter 5: "The nature of the inductive method is now clear." (page 188)

Robert Campbell

[BaalChatzaf]

Norsen also thoroughly trashed Lewis Little's nonsensical Theory of Elementary Waves, a favorite of the late Stephen Speicher (Betsy's husband).

Ba'al Chatzaf

Edited July 30, 2010 by BaalChatzaf

[tjohnson]

Have you considered the possibility that physicists use the words "space" and "time" with different meanings than we find in ordinary language?

Ghs

Indeed they do and they define their usage with ultra precision. Which is why physics succeeds and philosophy fails (among other reasons).

Ba'al Chatzaf

Okay, so give us an ultra precise definition of "space" and an ultra precise definition of "time."

If by "space" and "time" physicists mean something different than what people mean in ordinary discourse, then why do physicists use those words? Why didn't physicists choose other words, such as "ham" and "eggs," and redefine those words instead? Then they could explain, with ultra precision, the details of the ham and eggs manifold.

If you are going to use stipulative definitions to change the meaning of words, then what difference does it make which words you use?

Ghs

First of all, physicists don't use the word 'space' and 'time' by themselves anymore, they use 'space-time'. Secondly, it's not that they have an "ultra precise" definition of space-time, its just that they know quite a bit about it. Scientists are not very concerned with definitions, they are more interested in phenomena.

[Ellen Stuttle]

Norsen also thoroughly trashed Lewis Little's nonsensical Theory of Elementary Waves, a favorite of the late Stephen Speicher (Betsy's husband).

Ba'al Chatzaf

Quick questions of an "O'ist schisms" curiosity sort. Has anyone heard "boo" about Harry Binswanger's opinion of the Harriman? I think Norsen is still a regular on HBL.

Does anyone know of any public opinion being expressed from Leonard Peikoff or other official ARIans about TEW?

Ellen

[Ellen Stuttle]

If you are going to use stipulative definitions to change the meaning of words, then what difference does it make which words you use?

First of all, physicists don't use the word 'space' and 'time' by themselves anymore, they use 'space-time'.

They still use "space" and "time" in contexts more like standard parlance (though I hope "standard parlance" doesn't, as George indicated he thinks of the standard meaning of "space," generally mean what's left when there's "nothing"). They speak of "space," "time," and "space-time."

Secondly, it's not that they have an "ultra precise" definition of space-time, its just that they know quite a bit about it. Scientists are not very concerned with definitions, they are more interested in phenomena.

That, in my experience of knowing and reading physicists, I'd say is true. I don't know of any physicists consulting the verdict of philosophers before starting to use terminology in a particular way. (E.g., Faraday and the meaning of "field," which might cause even more troubles for non-physicists' understanding the physics meaning than "space-time.")

Ellen

Edited July 30, 2010 by Ellen Stuttle

[tjohnson]

If you are going to use stipulative definitions to change the meaning of words, then what difference does it make which words you use?

First of all, physicists don't use the word 'space' and 'time' by themselves anymore, they use 'space-time'.

They still use "space" and "time" in contexts more like standard parlance (though I hope "standard parlance" doesn't, as George indicated he thinks of the standard meaning of "space," generally mean what's left when there's "nothing"). They speak of "space," "time," and "space-time."

Secondly, it's not that they have an "ultra precise" definition of space-time, its just that they know quite a bit about it. Scientists are not very concerned with definitions, they are more interested in phenomena.

That, in my experience of knowing and reading physicists, I'd say is true. I don't know of any physicists consulting the verdict of philosophers before starting to use terminology in a particular way. (E.g., Faraday and the meaning of "field," which might cause even more troubles for non-physicists' understanding the physics meaning than "space-time.")

Ellen

I think this all gets back to the idea that there is a "correct" definition for each of our words, which causes interminable confusion and arguments. When a farmer talks about his field of corn he obviously doesn't think its the same kind of field as the electromagnetic one around the power lines. The fact is there are phenomena "out there", whether its the space between your teeth or the space-time continuum, and whats really important is what we can learn about these phenomena, not what we call them. Language has its own evolution and there's not much we can do about that, unless we want to start over and create a synthetic language. The term 'heat' appears to represent a substance and so alot of time and energy was put into isolating this 'substance', which turned out not to be a substance at all. In fact, even the word 'matter' is ambiguous on some level since by virtue of E=mc^2, matter is simply energy somehow "knit" together. All of these words are merely placeholders for some phenomena which we learn more about as "time" goes on.

[BaalChatzaf]

If you are going to use stipulative definitions to change the meaning of words, then what difference does it make which words you use?

First of all, physicists don't use the word 'space' and 'time' by themselves anymore, they use 'space-time'.

They still use "space" and "time" in contexts more like standard parlance (though I hope "standard parlance" doesn't, as George indicated he thinks of the standard meaning of "space," generally mean what's left when there's "nothing"). They speak of "space," "time," and "space-time."

Secondly, it's not that they have an "ultra precise" definition of space-time, its just that they know quite a bit about it. Scientists are not very concerned with definitions, they are more interested in phenomena.

That, in my experience of knowing and reading physicists, I'd say is true. I don't know of any physicists consulting the verdict of philosophers before starting to use terminology in a particular way. (E.g., Faraday and the meaning of "field," which might cause even more troubles for non-physicists' understanding the physics meaning than "space-time.")

Ellen

I think this all gets back to the idea that there is a "correct" definition for each of our words, which causes interminable confusion and arguments. When a farmer talks about his field of corn he obviously doesn't think its the same kind of field as the electromagnetic one around the power lines. The fact is there are phenomena "out there", whether its the space between your teeth or the space-time continuum, and whats really important is what we can learn about these phenomena, not what we call them. Language has its own evolution and there's not much we can do about that, unless we want to start over and create a synthetic language. The term 'heat' appears to represent a substance and so alot of time and energy was put into isolating this 'substance', which turned out not to be a substance at all. In fact, even the word 'matter' is ambiguous on some level since by virtue of E=mc^2, matter is simply energy somehow "knit" together. All of these words are merely placeholders for some phenomena which we learn more about as "time" goes on.

Definitions are conventions in the use of language. There are no "correct" definitions, only definitions agreed upon in various contexts and situations. The is no God of Languages handing down Definitions scribed on tablets of stone.

Ba'al Chatzaf

[George H. Smith]

Definitions are conventions in the use of language. There are no "correct" definitions, only definitions agreed upon in various contexts and situations. The is no God of Languages handing down Definitions scribed on tablets of stone.

Ba'al Chatzaf

I think I will define "physics" as the discipline that claims mystical insight, based on faith, into the nature of reality. Yeah, that's the ticket. No one can legitimately call my definition "incorrect." It may be unconventional, but so what? There is no God of Language that I need worry about, after all.

“I don’t know what you mean by ‘glory,’ ” Alice said.

Humpty Dumpty smiled contemptuously. “Of course you don’t -- till I tell you. I meant ‘there’s a nice knock-down argument for you!’ ”

“But ‘glory’ doesn’t mean ‘a nice knock-down argument’,” Alice objected.

“When I use a word,” Humpty Dumpty said, in a rather a scornful tone, “it means just what I choose it to mean -- neither more nor less.”

“The question is,” said Alice, “whether you can make words mean so many different things.”

“The question is,” said Humpty Dumpty, “which is to be master -- that’s all.”

--Lewis Carroll, Through the Looking Glass

Ghs

[Xray]

In that context, it would interest me if you were born into and brought up in a religion.

No. I remember that when I was a toddler, my mother told me a bit about our good Lord in heaven (I also remember that I tended to confuse him with a pilot) and I've been baptized ("you never know"), but that's all, no prayers, no church and all that jazz. Today I think my parents were at most some kind of deists. When I was about 12 years old, I'd left all that behind me.

So you were never confronted with the interfering doctrine and dogma of a faith directing your life.

I was born and raised a a catholic, and although my parents were religiously not very interested, the catholic church had its strong grip on the school system. Looking back, I ask myself how I managed to live with the idea of this "ever-present voyeur", the "god" of the catholic church. (The credit for the apt expression "ever-present voyeur" goes to George H. Smith who used it in his book "Why Atheism").

Definitions are conventions in the use of language. There are no "correct" definitions, only definitions agreed upon in various contexts and situations. The is no God of Languages handing down Definitions scribed on tablets of stone.

Ba'al Chatzaf

I think I will define "physics" as the discipline that claims mystical insight, based on faith, into the nature of reality. Yeah, that's the ticket. No one can legitimately call my definition "incorrect." It may be unconventional, but so what? There is no God of Language that I need worry about, after all.

You have disregarded the key element "agreed upon" in Ba'al's post. That is, you can't just define e. g. "butter" as something it is not without running into substantial problems in communication.

Imagine your wife at table asks you to pass her the butter, and you hand her a fork instead; after her puzzled look, you reply "My definition of "butter" is this: 'a tool for eating, with tines'."

So while there exists no God of language, there exists convention in language and there is not much room for arbitrary definitions.

What you personally connote with a word is another issue. Connotations and associations are virtually limitless.

Rand often made the mistake of presenting as "objective" definition what was in fact her personal association/connotation with a term (as e. g. with "sacrifice").

I have no problem if physicists assign different meanings to common words, so long as they are clear that this is what they are doing. And if they are clear about this, then they will need to exercise extreme caution when announcing their conclusions to a lay audience, making grand pronouncements to the effect that physics has shown that our commonsense notions about "space" and "time" are wrong. (Claims like this have been made on OL.)

If it was a physicist who claimed that on OL, imo his/her intention was to direct our attention to complexities we are not aware of.

It is not my intention to denigrate physics; far from it. My problem is with those physicists, or those people who claim to know something about physics, who draw unwarranted conclusions -- many of them philosophical -- from the findings of physics.

The far more problematic group are those believers/ideologists who reject scientific findings which don't fit their belief/philosophy/ideology.

A physicist, however brilliant, does not have a special epistemological warrant to speak nonsense and then, when a layperson points out that he is speaking nonsense, flash his scientific credentials, while claiming that nonspecialists cannot understand the profundity of his statements.

How can a layerson having only little or no knowledge in a physicist's field of expertise assess that the physicist "speaks nonsense"?

If a physicist believes that he cannot adequately express his conclusions in conventional language, because they would make no sense, then he should candidly admit this. In this case we would be confronted with one of two possibilities: either the mysteries of physics are inexpressible (rather like the Trinity and other "truths" of theology), or the physicist has not learned how to express himself intelligibly. I would always wager on the latter possibility.

There exist enough books written for interested laypersons by world-famous physicsts who are perfectly able to "express themselves intelligibly".

Edited July 30, 2010 by Xray

[George H. Smith]

You have disregarded the key element "agreed upon" in Ba'al's post. That is, you can't just define e. g. "butter" as something it is not without running into substantial problems in communication.

I have made the same point several times in previous posts.

Rand often made the mistake of presenting as "objective" definition what was in fact her personal association/connotation with a term (as e. g. with "sacrifice").

If physicists can redefine words, then why can't philosophers?

Rand's theory of definitions is very good. It leaves ample room for different definitions of the same word, depending on the context.

How can a layperson having only little or no knowledge in a physicist's field of expertise assess that the physicist "speaks nonsense"?

Use the same standards that you would apply to anyone else. For example, you don't need to be an expert in physics to realize that attributing "free will" to subatomic particles is nonsense.

There exist enough books written for interested laypersons by world-famous physicists who are perfectly able to "express themselves intelligibly".

I never denied this. But if you read such books, you will find that these physicists sometimes reach different philosophical conclusions, and they also disagree about the nature of the concepts and theoretical models used in physics. So be careful: Given your propensity to genuflect before scientific "experts," all that twisting and turning might throw your back out.

Ghs