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Thread: The speed of light - 299,792,458 m/sec - why that number.

  1. #31
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    Quote Originally Posted by grapes View Post
    Rather than measuring the speed of the propagation of electromagnetic waves, I would say he calculated what it would be, given his "laws".

    There has been a recurrent question in this thread about what it means to measure, and that certainly comes into play here, but not having actually witnessed the propagation of waves, I would tend to say that he didn't measure the propogation of waves, per se.
    Yes, Maxwell himself did not carry out those observations personally, but he used them to set the parameters in his theory. That's the only point I'm making-- the parameters in a theory are just critically positioned placekeepers, only observations can fill in those blanks with actual values. So Maxwell did not predict the speed of light, he predicted that the speed of light (or its correlates in the shell game) is one of those important blanks, appearing in electromagnetic theory. Indeed, I have seen it argued that mostly he borrowed from the work of others, and took most of the credit, kind of like how Brutus gets the credit for assassinating Caeser.

  2. #32
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    Quote Originally Posted by Jeff Root View Post
    In this case, it is especially meaningful to say that Maxwell
    predicted the speed of light, because (as I understand it), he
    had no idea that the equation involving permeability and
    permittivity would result in that speed. When he got a value,
    he saw that it was close to the measured speed of light, and
    realized that that is what he had calculated.

    -- Jeff, in Minneapolis
    Yes, I think your example is a valid application of retrodiction along with the other appropriate comments that followed.

  3. #33
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    Quote Originally Posted by forrest noble View Post
    Yes, I think your example is a valid application of retrodiction
    But why retrodiction? In the discussion (with all the caveats), he calculated that the speed of electromagnetic waves would be the same as the speed of light. How is that a retrodiction?

    Would you consider it a retrodiction if the calculation had shown that the speed of electromagnetic waves was different from the speed of light? How is that any different?

  4. #34

    Oh, really?

    Quote Originally Posted by Ken G View Post
    {Snip!} Making after-the-fact claims is actually more the domain of science than philosophy. Philosophy is the effort to make before-the-fact claims, which is indeed quite a difficult challenge.
    Oh, really? Can you please give a few examples of successful before-the-fact claims made by philosophers? Other than Kant's lucky guess about the nature of galaxies?

  5. #35
    Quote Originally Posted by Celestial Mechanic View Post
    Oh, really? Can you please give a few examples of successful before-the-fact claims made by philosophers? Other than Kant's lucky guess about the nature of galaxies?
    I can't see the justification for the red flag response based on the word "effort". How is a true statement of the Philosophers' effort a claim at successful prophesies by philosophers?

  6. #36
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    Quote Originally Posted by a1call View Post
    I can't see the justification for the red flag response based on the word "effort". How is a true statement of the Philosophers' effort a claim at successful prophesies by philosophers?
    I think CM is just pointing to whether or not the effort is justified.

    I, of course, think it is.

  7. #37
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    Quote Originally Posted by Celestial Mechanic View Post
    Oh, really? Can you please give a few examples of successful before-the-fact claims made by philosophers? Other than Kant's lucky guess about the nature of galaxies?
    Of course philosophers have anticipated essentially every basic principle that science has ever discovered, just as science fiction writers have anticipated virtually every technology. They also anticipated everything that was not discovered. My point was merely in clarifying the attempts, not gauging the success. Indeed, I would point out that science never predicts the future, it always predicts the past before it happened (just look at how science works). Using science to predict the future is always an exercise in philosophy, and a rather important one at that.

  8. #38
    Quote Originally Posted by Ken G View Post
    Of course philosophers have anticipated essentially every basic principle that science has ever discovered, just as science fiction writers have anticipated virtually every technology.
    "Philosophers take credit for everything ...", check.
    Quote Originally Posted by Ken G View Post
    They also anticipated everything that was not discovered. My point was merely in clarifying the attempts, not gauging the success.
    "... and responsibility for nothing.", check. Thank you for making my case.
    Quote Originally Posted by Ken G View Post
    Indeed, I would point out that science never predicts the future, it always predicts the past before it happened (just look at how science works). Using science to predict the future is always an exercise in philosophy, and a rather important one at that.
    Science is very bad at predicting futures full of flying cars and 20-hour work weeks, that is true. But predicting eclipses years in advance is hardly "an exercise in philosophy".

    But back to the topic (remember the topic?): I think that what we have in the case of Maxwell's electromagnetism is a case, not of prediction or retrodiction, but of identification. The theory predicted waves, true, but calculation showed that their speed was (to within the precision of the time) identical to the measured speed of light. A new description (or model if you prefer) was found for something long known.

  9. #39
    Quote Originally Posted by a1call View Post
    Since 1983 that speed is a matter of convention.
    I concur with a1call on this. I imagine that the particular number chosen represented some number that was a weighted average of the (then) most recent results for the measurement of the speed of light.

    Spacetime is a unified object, there is no separate time or space. The problem is that we perceive and measure both very differently, and that reasonable measures of distance are too small compared to everyday time measures and that reasonable measures of time are too large compared to everyday distance measures. The speed of light (in a vacuum) represents a conversion factor between two ways of measuring intervals in spacetime.

  10. #40
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    Quote Originally Posted by Celestial Mechanic View Post
    "Philosophers take credit for everything ...", check.
    It is only a fundamental misunderstanding what philosophy is for that leads to the entire concept of "credit" in the first place. Philosophy is not a grab for credit, it is an exercise in understanding thought, discourse, and reason itself. Smaller minds worry about the credit, even men like Galileo, Newton, and Einstein tended to cast their accomplishments in humble terms, along the lines of "don't be too impressed by my genius, because above all what it lets me see is how little I really understand." They were all philosophers, in addition to scientists, as any cursory examination of their most famous quotes quickly demonstrates.
    "... and responsibility for nothing.", check. Thank you for making my case.
    Your case is going on inside your own head-- it has nothing to do with what philosophy actually is. Don't worry, your misunderstanding of the purpose of philosophy is not your own fault, it is extremely widespread. It happens when people ask philosophy to do what science does, and science to do what philosophy does. I see it all the time.
    Science is very bad at predicting futures full of flying cars and 20-hour work weeks, that is true. But predicting eclipses years in advance is hardly "an exercise in philosophy".
    Actually, science does not predict eclipses in the future, it predicts eclipses in the past, but before they happened. That's just what science does-- it looks at the past, finds patterns, hypothesizes rules from those patterns, and checks those rules by looking at past observations. No scientist ever checked the future, they always checked the past, even when they made their prediction even farther in the past. It is philosophy to use that body of information to predict the future-- the philosophy that what has happened in the past is a good bet to happen again. Science can test that bet too-- but only once it is also in the past. This is a classic example of how science and philosophy cooperate, but those who don't notice the differences think it's all science. They use philosophy all the time, yet discredit philosophy, simply because they can't tell when they are using it. It usually boils down to the idea that "philosophy is the way other people think-- the way I think is never philosophy."
    But back to the topic (remember the topic?):
    Yes, let's get away from your excursion (and grapes', who was the first person to mention philosophy) into misconceptions about philosophy, by all means.
    I think that what we have in the case of Maxwell's electromagnetism is a case, not of prediction or retrodiction, but of identification. The theory predicted waves, true, but calculation showed that their speed was (to within the precision of the time) identical to the measured speed of light. A new description (or model if you prefer) was found for something long known.
    I think it's fair to say that the main breakthrough that Maxwell contributed to was the recognition that light could be treated as a wavelike electromagnetic phenomenon, as grapes already pointed out.

  11. #41
    Quote Originally Posted by Ken G View Post
    {Snip!} Actually, science does not predict eclipses in the future, it predicts eclipses in the past, but before they happened.
    So what exactly are all those eclipses predicted for future times in works by Oppolzer and Meeus -- chopped liver? This is murky philosophical word-salad at its worst. I know that there will be a solar eclipse on 2017 August 17 as long as the Solar System still exists then in its current form.
    Quote Originally Posted by Ken G View Post
    That's just what science does-- it looks at the past, finds patterns, hypothesizes rules from those patterns, and checks those rules by looking at past observations. No scientist ever checked the future, they always checked the past, even when they made their prediction even farther in the past. It is philosophy to use that body of information to predict the future-- the philosophy that what has happened in the past is a good bet to happen again.
    {Emphasis mine.}
    But the emphasized part of the quote is really nothing more than a truism, not the sort of deep, world-shaking stuff that is supposed to pass for philosophy.

  12. #42
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    Quote Originally Posted by Celestial Mechanic View Post
    So what exactly are all those eclipses predicted for future times in works by Oppolzer and Meeus -- chopped liver?
    To understand this, all you have to do is keep track of what science actually does, and what philosophy actually does. Philosophy is about making choices about what you will believe to be proper or correct, based on rational thought. That's just exactly what philosophy is, people who bash it just have no idea what it is (since they do it all the time themselves). Science, on the other hand, does something rather different (though there are areas of overlap that are too off topic to mention)-- it notices patterns, finds rules, and checks them. So here's what science does in regard to eclipses: it notices patterns, and predicts a new eclipse. Then it waits to verify the prediction. After the event is in the past, it checks if the prediction was right. If it was, the theory survives to be checked again, if it doesn't, the theory gets modified. So science predicts the past before it happens. When people ask me if I "believe" in some theory, I feel puzzled by such a nonscientific question-- I presume they want me to give my own scientifically informed philosophy on the subject, but I'm not sure they realize that's what they are asking for.

    Now, if one wishes to take a stance that a prescription for predicting eclipses that has worked a thousand times is going to work the next time also, that is a philosophical stance. Science has no idea if it will work again, nor cares-- indeed it generally prefers if it does not-- it's so much more interesting. Making choices about life, based on science, is something very different-- that's philosophy, and that's where it's nice when the scientific predictions are correct. So that's why I said that science is backward-looking, insofar as it is self-correcting, but philosophy is forward-looking, insofar as it is about making choices.

    This is murky philosophical word-salad at its worst.
    One thing I've noticed countless times-- people who use the phrase "word salad" seem to miss how completely self-referential that phrase invariably is. They may as well have said nothing, the words carry no logical content.
    I know that there will be a solar eclipse on 2017 August 17 as long as the Solar System still exists then in its current form.
    Again, a reasonably good definition of philosophy is the prescription for deciding what you believe is true. Look it up.

  13. #43
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    My philosophy:

    I disagree with you about what philosophy is.
    I agree that everyone who is able to think even remotely like normal
    for a human is a philosopher, as a large part of their conscious thought--
    and maybe a large part of their unconscious thought-- is philosophising.
    I'd say that there is a very large area of overlap between science and
    philosophy, since the parts of science that involve thinking consist to a
    large extent of philosophy.
    I consider logic to be pretty much a subset of philosophy. (Though that
    notion was probably influenced by the fact that the course in logic at
    the U of M was part of the philosophy department, which struck me as
    slightly goofy. I figured it wasn't under the math department only for
    historical reasons.)
    I consider mathematics to be largely a subset of logic. And I consider
    the thinking-dependant part of science to also be largely a subset of
    logic.

    I think there is a difference between philosophy and reasoning, but
    I'm not sure what it is. Logic is clearly a subset of reasoning. I think
    there is a difference between philosophy and making judgements,
    but I'm not sure what it is. Making judgements would appear to be
    a subset of philosophy, but not necessarily a subset of reasoning.

    If your impression is that people who use the phrase "word salad"
    seem to miss how completely self-referential that phrase invariably
    is, then that impression is probably based almost entirely on those
    people applying the expression to your words. When I see it applied
    to other people's words, it is almost always spot-on. Your words, on
    the other hand, sometimes (not rarely) seem intended primarily to
    shock, by being exactly the opposite of what most people would
    expect, and when you do that, the reader is presented with a jumble
    of words that seem disorganized. It usually appears at first that you
    misspoke, but that never turns out to be the case. You seem to have
    a supernatural ability to avoid making any kind of error at all, even
    while saying the apparently most outlandish things. It is scary.

    Do people who meet you in person ever tell you anything like this?

    -- Jeff, in Minneapolis
    http://www.FreeMars.org/jeff/

    "I find astronomy very interesting, but I wouldn't if I thought we
    were just going to sit here and look." -- "Van Rijn"

    "The other planets? Well, they just happen to be there, but the
    point of rockets is to explore them!" -- Kai Yeves

  14. #44
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    Quote Originally Posted by Jeff Root View Post
    I disagree with you about what philosophy is.
    If you google "definition philosophy", the first hit is
    http://www.bing.com/Dictionary/searc...ion+philosophy, which defines it as
    "examination of basic concepts: the branch of knowledge or academic study devoted to the systematic examination of basic concepts such as truth, existence, reality, causality, and freedom
    2. school of thought: a particular system of thought or doctrine
    3. guiding or underlying principles: a set of basic principles or concepts underlying a particular sphere of knowledge
    4. set of beliefs or aims: a precept, or set of precepts, beliefs, principles, or aims, underlying somebody's practice or conduct
    5. calm resignation: restraint, resignation, or calmness and rationality in somebody's behavior or response to events"
    I'd say that's just bang-on, though I agree with you that ten philosophers will have ten different angles on what philosophy is. That's not surprising-- ten scientists will have ten angles on what science is too. In a very real sense, there are really two things that are "science" and two that are "philosophy"-- the union of those different angles, and their intersection. I would say the core intersection of science is making predictions and testing them once they are in the past, and the core intersection of philosophy is making rational choices about what you believe (when the rationality constraint is lifted, beliefs enter more into the religious realm-- not to say that religiion is irrational, but rather that it does not invoke rationalism).
    I'd say that there is a very large area of overlap between science and
    philosophy, since the parts of science that involve thinking consist to a
    large extent of philosophy.
    No question, there is that overlap-- by drawing the distinctions I am attempting to tease out the differences rather than the similarities. Just because both involve swallowing does not mean we cannot tell the difference between eating and drinking.
    I consider logic to be pretty much a subset of philosophy. (Though that
    notion was probably influenced by the fact that the course in logic at
    the U of M was part of the philosophy department, which struck me as
    slightly goofy. I figured it wasn't under the math department only for
    historical reasons.)
    Logic is an accepted tool of philosophy, so I'd place it as part of the definitional architecture of philosophy moreso than a subset of it, but I don't think we are disagreeing.
    I consider mathematics to be largely a subset of logic. And I consider
    the thinking-dependant part of science to also be largely a subset of
    logic.
    Logic is an accepted tool in both math and science too, it's the core intersection of all those disciplines. Math is more than logic though, because logic is just a structure for proving-- math also includes the selection of axioms on which to apply logic. The criteria for selecting axioms can be very different in math than in either philosophy or science-- for example, Riemann was interested in relaxing the parallel postulate before there was any reason to think it would be important to do so in science, and it still has no particular importance in philosophy.
    I think there is a difference between philosophy and reasoning, but
    I'm not sure what it is.
    Yes, that's a crucial issue. At the least, I'd say the differences are the goals one has for doing the reasoning, and the criterion used to decide on what axioms are of interest.
    If your impression is that people who use the phrase "word salad"
    seem to miss how completely self-referential that phrase invariably
    is, then that impression is probably based almost entirely on those
    people applying the expression to your words.
    It makes no difference whose words they are applied to, my objection is the absence os logic. Show me the mathematical proof that can be dismissed as incorrect because it is "word salad." The fact is, any idea interesting enough to require more than two sentences to describe can be easily dismissed as "word salad" when that is the only evidence the objectioner can bring to bear on the issue (which it invariably is). I like logic better.

    When I see it applied to other people's words, it is almost always spot-on.
    Again, it makes no difference if the words are saying something or not-- anyone who does not understand them will think they are not. The point of rational discourse it so dissect them and determine their content, not dismiss them without even understanding them because it would take effort.

    You seem to have
    a supernatural ability to avoid making any kind of error at all, even
    while saying the apparently most outlandish things. It is scary.
    Thank you. I must confess that I do cultivate a bit of "shock value" into my points, but frankly, I feel we are all far less shocked by our universe than we ought to be.
    Do people who meet you in person ever tell you anything like this?
    Sometimes, yes. I don't mind a bit of flying fur, but perhaps it happens even more with the written word and the impersonal internet environment.

  15. #45
    Quote Originally Posted by Ken G View Post
    Of course philosophers have anticipated essentially every basic principle that science has ever discovered, just as science fiction writers have anticipated virtually every technology. They also anticipated everything that was not discovered. {Snip!}
    Very well, then. Please tell me which philosophers anticipated the following basic principles:

    . The value of the speed of light. Not the actual value later adopted, but just an order of magnitude value.
    . The equality of the product of the permittivity and permeability being equal to the inverse square of the speed of light for the medium.
    . Constancy of the speed of light in vacuo.
    . Principle of least action.
    . Gauge principle.

    I've never seen the names of Descartes, Kant, Hegel, Schopenhauer, Nietzsche or Sartre linked to any of these things. Aristotle's ideas of mechanics were mostly wrong, Descarte's explanation of celestial mechanics by means of vortices was completely wrong, and Kant's idea of "island universes" was a lucky guess. As for "Mach's Principle", there is no clear statement of it anywhere in Mach's writings for us to judge its validity.

    Or were the philosophers who actually did "anticipate" the stuff on the above list too "humble" to write these things down so they wouldn't be given credit for these things?

  16. #46
    Quote Originally Posted by Celestial Mechanic View Post
    . The value of the speed of light. Not the actual value later adopted, but just an order of magnitude value.
    . The equality of the product of the permittivity and permeability being equal to the inverse square of the speed of light for the medium.
    . Constancy of the speed of light in vacuo.
    . Principle of least action.
    . Gauge principle.
    I'm not entirely clear as to what a "principle" is. In that list, the first item, the speed of light, seems like an observation rather than a principle. Except for the principle of least action, they all seem almost like observations rather than principles. Maybe it's like this, that if you measure the speed of light 100 times and get the same figure, you make a principle that "the speed of light is always this figure."
    As above, so below

  17. #47
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    Quote Originally Posted by Celestial Mechanic View Post
    Very well, then. Please tell me which philosophers anticipated the following basic principles:

    The value of the speed of light. Not the actual value later adopted, but just an order of magnitude value. The equality of the product of the permittivity and permeability being equal to the inverse square of the speed of light for the medium.
    . Constancy of the speed of light in vacuo.
    . Principle of least action.
    . Gauge principle.

    I've never seen the names of Descartes, Kant, Hegel, Schopenhauer, Nietzsche or Sartre linked to any of these things. Aristotle's ideas of mechanics were mostly wrong, Descarte's explanation of celestial mechanics by means of vortices was completely wrong, and Kant's idea of "island universes" was a lucky guess. As for "Mach's Principle", there is no clear statement of it anywhere in Mach's writings for us to judge its validity.

    Or were the philosophers who actually did "anticipate" the stuff on the above list too "humble" to write these things down so they wouldn't be given credit for these things?
    Your entire post is just a repetition of your incorrect ideas that philosophy is just another less successful route to generating scientific theories. That's not what philosophy is, so when I say that philosophy aniticipates science, I do not mean it formulates scientific theories in advance of science. Instead, philosophy has different goals than science, and looks different than science. As I said above, philosophy is about how you will know something, whether it be by trusting your senses (what Kant called a posteriori knowledge) or by trusting pure logic (what Kant called a priori knowledge). This is also the tension between empiricism and rationalism, dating back to debates between Heraclitus and Parmenides (they were ancient Greeks). As science tries to make a unification of the senses and reason (observation and theory), it relies heavily on the groundwork established in both those philosophical camps.

    So if it is not the goal of philosophy to create scientific theories that make testable predictions, then to what extent can I claim that philosophy anticipates scientific discoveries? By identifying the intellectual landscape that the scientific path will later follow. In this spirit, we can address your examples, though more detail in each area would probably require significant research and might actually generate a rather reasonable project at, perhaps, the level of a philosophy Ph.D. dissertation:

    *The value of the speed of light, even to within an order of magnitude, is not a "fundamental principle" at all, it is an arbitrary detail that requires measurement. Fundamentally, the existence of a speed of light is essentially the assertion that events cannot affect other events arbitrarily quickly. The philosopher who most clearly anticipated this idea was Einstein (remember, Einstein always claimed that he arrived at relativity not by the outcome of experiments like Michelson-Morely, but by the necessity of the logic itself, a quintessentially philosophical stance). But if we count Einstein a scientist moreso than a philosopher, we might instead look for his philosophical inspirations from earlier works, expressly the vast philosophical literature about space and time, including (again) Parmenides, right up through Newton and Liebnitz (around their philosophical debates about the nature of space), and ultimately to Mach (another person who did both science and philosophy, but when we was doing either is clear enough). One might also track the philosophical history about cause and effect, so essential are those concepts to the idea of a finite speed limit for propagating influences, so that would bring in the core debate centering on Hume and Kant. As just one specific example of what such a journey might uncover, we can just look to Newton's famous philosophical musing about action at a distance:
    " That gravity should be innate, inherent, and essential to matter, so that one body may act on another body at a distance through a vacuum, without the mediation of any thing else by and through which their action and force may be conveyed from one to the other, is to me so great an absurdity that I believe no man who has in philosophical matters a competent faculty of thinking can ever fall into it. Gravity must be caused by an agent acting constantly according to fixed laws ; but whether this agent be [72] material or immaterial I have left to the consideration of my readers."
    Here Newton is clearly engaging in the best tradition of philosophical thinking, insofar as he is placing a modern scientific principle into a context of ancient tenets of rational plausibility laid out well in advance by pure philosophy.

    * Constancy of the speed of light: Here we have but a single example of a much deeper scientific concept, that of a constant of nature. The existence of constants of nature is also a long-standing philosophical sphere of debate, from Parmenides (that many ideas date back to him is a result of his being essentially the father of rationalist philosophical argumentation), who maintained that change was logically an a priori impossibility so the senses delude us, and hence not only the speed of light but indeed everything is a constant of nature, and including the perfect forms of Plato, but good philosophy always calls on us to consider the alternatives: Alfred North Whitehead felt that laws of nature should be allowed to themselves evolve, such that any constant of nature should be regarded (paraphrasing) as a "constant" like your own height, something that behooves you to treat as constant on the forms you fill out, but which is not taken literally as a necessary constant. So again we see the kinds of things that philosophy does, in advance of actual scientific theories-- it lays the rational groundwork for the theories that come later, and can be of many specific forms.

    *Principle of least action-- Here we have an example of an extremum principle, and the philosophical literature has of course crisscrossed the landscape of extremum principles extensively, whereby nature is thought to be achieving some kind of maximum perfection. Again it is not the role of philosophy to stipulate the algebraic quantity we should associate with the extremum principle, but rather to lay the groundwork of what an extremal principle would logically entail, and how they might be manifested in nature. When I said philosophy anticipates every discovery that science makes and every discovery it does not make, I mean that philosophy walks the roads through which science will tread, not that it guesses at every possible arithmetic form that nature could possibly maximize-- the latter would be a pointless exercise for philosophy, it is the purvey of science to ascertain what arithmetical forms an extremal principle should take.

    *Gauge theories-- also a deeply philosophical topic. The concept of a gauge is that a law of physics might take on a very different form yet assert the same physical consequences when restricted to the space in which other physical constraints are in play, typically symmetries. The language of gauge theories is certainly much closer to mathematics than philosophy, but again the basic path laid out by gauge-theory thinking has been well tread by philosophy, in the area of asking how much can really be asserted is true, and what kinds of ambiguities exist in any such assertion. For example, Newton, acting in his role as a philosopher, laid out what he called his first rule of inference:
    "Rule I: One should not allow more causes of natural phenomena than are true and sufficient to explain them."
    This is a metaphysical stance about what our language about nature should be like, akin to Occam's Razor, and belongs in the same tapestry in regard to symmetries and amibiguities of nature that gauge theories exemplify. Specifically, the direct connection with gauge theories is the recognition that choosing a gauge is like taking a stance on a symmetry or physical ambiguity that is "more cause" than is "sufficient". Hence Newton's caution against doing that is a precursor to the importance of noticing that when one gauge is selected, it is arbitrary, and in some other situation, a different gauge might produce clearer or more conveniently tractable results.

    And that was your chosen list. Were I to choose a list of philosophically anticipated groundwork of later (often much later) scientific theories, I would point to theories of atoms, of fields, of unitary evolution of "stationary" states (a nod to Parmenides again), of a universe of finite age, of the "landscape", of Penrose's cyclical universe (cosmology is great for philosophically anticipated concepts), of occult "virtual particles" mediating actions at a distance, and so on.

  18. #48
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    Quote Originally Posted by Ken G View Post
    Actually, science does not predict eclipses in the future, it predicts eclipses in the past, but before they happened.
    I've read your subsequent posts, and I think I'm sure of what you're getting at (and I agree with that), but I'm still shocked at this sentence.

    So, I'd like to try a paraphrase of my own, with a timeline, and a question or two. Today is 2011, so a scientist in 2000 might predict an eclipse in 2005, and we know today that the prediction is accurate. A scientist today might predict an eclipse in 2015, but we won't know until then how accurate the prediction is. Is that it?

    Is the 2011/2015 prediction a scientific prediction, or is it just a philosophical belief? How much accuracy is required before the prediction is wrong? Nobody expects absolute perfection, right?
    Quote Originally Posted by Ken G View Post
    Yes, let's get away from your excursion (and grapes', who was the first person to mention philosophy) into misconceptions about philosophy, by all means.
    I was the first to use the word "philosophy" but I was responding to philosophy.

    I'm a big advocate of philosophy. But to be realistic, there are far more successful charlatans in that field, than in the science field--and the science field has its share.
    I think it's fair to say that the main breakthrough that Maxwell contributed to was the recognition that light could be treated as a wavelike electromagnetic phenomenon, as grapes already pointed out.
    There's that, and apparently some also took it to mean that electromagnetic waves could propagate--and that they might be useful for distance communications.

  19. #49
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    Quote Originally Posted by grapes View Post
    Today is 2011, so a scientist in 2000 might predict an eclipse in 2005, and we know today that the prediction is accurate. A scientist today might predict an eclipse in 2015, but we won't know until then how accurate the prediction is. Is that it?
    Yes exactly-- if one looks carefully at the structure of science, one sees that it is about making predictions and testing them. But there is no step in the scientific method like "step 6: believe your prediction." That's just not part of science, indeed, more correctly it would have "step 6: maintain skepticism about your prediction."

    Now, you are certainly right that in practice, as scientists we are going to believe our science most of the time. That's just human nature, and also, it informs our decisions about the future. But my point is, we have actually stopped doing science at that point-- we have a adopted a philosophy about science.
    Is the 2011/2015 prediction a scientific prediction, or is it just a philosophical belief?
    It's both, usually. But the science part doesn't treat the future prediction as anything important until it is in the past-- at which point it can be tested. That's when science cares about that prediction. Philosophy cares as soon as its made. That's really all I mean-- the words can sound like something different, but I just mean that the standard idea that "science empowers us to predict the future" is actually not a scientific statement at all.
    I'm a big advocate of philosophy. But to be realistic, there are far more successful charlatans in that field, than in the science field--and the science field has its share.
    I'd say it's just easier to spot, and discount, the scientific charlatans. If we count them all, like every creationist, then there's a very large number.
    There's that, and apparently some also took it to mean that electromagnetic waves could propagate--and that they might be useful for distance communications.
    I suspect it was already known experimentally that E&M propagated-- even before the equations described it. I could be wrong there.

  20. #50
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    Quote Originally Posted by Ken G View Post
    It's both, usually. But the science part doesn't treat the future prediction as anything important until it is in the past-- at which point it can be tested. That's when science cares about that prediction. Philosophy cares as soon as its made. That's really all I mean-- the words can sound like something different, but I just mean that the standard idea that "science empowers us to predict the future" is actually not a scientific statement at all.
    I thought that was it. But...

    would you object to saying "science has empowered us to predict the future"? (with the emphasis as perfective past tense) I mean, successful moon landings (yes, there were some), chromosomal tinkering, structural engineering (OK, some spectacular failures), and telecommunications have all empowered us. There is some credit due to the scientific method, no?
    I'd say it's just easier to spot, and discount, the scientific charlatans. If we count them all, like every creationist, then there's a very large number.I suspect it was already known experimentally that E&M propagated-- even before the equations described it. I could be wrong there.
    Well, creationists count as philosophical charltans too.

    I dunno for sure, I'll look it up.

  21. #51
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    Quote Originally Posted by grapes View Post
    would you object to saying "science has empowered us to predict the future"?
    Yes-- it empowered us to predict what was then the future but is now the past, the tested record shows that it gave us that power (most of the time). Also, the best justification for doing science is the philosophy that it will continue to show similar success going forward. No question this philosophy about science is the reason we have science, it is the means by which philosophy gave birth to science (via the development of "natural philosophy").
    I mean, successful moon landings (yes, there were some), chromosomal tinkering, structural engineering (OK, some spectacular failures), and telecommunications have all empowered us.
    Right, but none of those things are science, they are engineering. What I mean by science is the execution of the scientific method, for the purpose of making discoveries. Yes that is a rather narrow definition of what science is, but that's what pure science is-- i.e., science that is not mixed with other disciplines (like engineering and philosophy).
    Well, creationists count as philosophical charltans too.
    That's hard to say. A philosophical charlatan is not one who holds to a seemingly absurd idea, it is someone who holds to an idea that is internally inconsistent, or otherwise fails to follow the thought processes accepted as valid for philosophy. Philosophy bumps its right elbow with theology even as it bumps its left elbow with science. To me, the defining character of creationism, and its most objectionable feature, is not its claims that the universe had a creator, it is its claim that it is scientific to assert such. As a philosophy, believing that the universe had a creator that could suspend the laws of physics is not a philosophical problem-- it is just unscientific to invoke the suspension of the same laws that science is trying to test.

  22. #52
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    Quote Originally Posted by Ken G View Post
    Quote Originally Posted by grapes View Post
    would you object to saying "science has empowered us to predict the future"?
    Yes-- it empowered us to predict what was then the future but is now the past, the tested record shows that it gave us that power (most of the time).
    Yes, you would object? or yes, it has empowered us?

    Sorry, I want to clear that up before answering the rest of the post.

  23. #53
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    Quote Originally Posted by grapes View Post
    Yes, you would object? or yes, it has empowered us?

    Sorry, I want to clear that up before answering the rest of the post.
    I would put it like this. Philosophy needed an arm that could help deal with natural phenomena, as philosophy determined that it should be possible to get power over natural phenomena by studying them in some particularly effective way. Science is the device it created to achieve that, and it works. But it is philosophy that determines that science works, science is something much simpler: it is the scientific method. So the analogy is, the hunter/philosopher wanted to hunt deer, so he/she devised a technique for studying weapons that would result in a useful weapon, with the help of an engineer. The technique for studying resulted in the engineering of the bow and arrow. The philosopher/hunter uses the bow and arrow to hunt deer. The bow and arrow does not hunt deer, it is just a device for propelling an arrow. Now, I don't mean that scientists have to turn their discoveries over to philosophers and engineers to be useful, instead we all wear these different hats. I'm just distinguishing the hats.

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    Science doesn't kill people, philosophy does?

    I still think the question is, does it work? Has it empowered us to predict the future?

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    Quote Originally Posted by grapes View Post
    Science doesn't kill people, philosophy does?
    Exactly! And that's only partly a joke-- there have been cases in history where the truth of that is gravely clear.
    I still think the question is, does it work? Has it empowered us to predict the future?
    That depends on which "future" you mean (the one that is now in the past, or the one that isn't), and whether or not your philosophy is that past patterns are predictive of future events, going forward from now. When you buy stocks from a broker, there is always that disclaimer-- science doesn't come with the disclaimer, because it has a much clearer record of past success, but big discoveries in science come from people who recognize that past models might not be the most workable for future experiments, even if they have worked well in the past.

    Personally, I think there needs to be kind of philosophical concept of a "similar experiment" in science. When we drop a block or a marble, it falls, so we expect dropping a jack to be a "similar experiment", so it should also fall. Or we can have a bit different rationale for expecting similarity, like if we just dropped a jack ten times, and it fell in all of them, and this is the eleventh time in a row-- that's more clearly going to be a "similar experiment." The reason we regard it as similar is we have no reason to expect a difference. But that doesn't mean it really is similar-- maybe the jack has a charge on it, and there's an electric field in the room we didn't know about when we dropped the block and the marble, or that just turned on after the last ten drops of the jack. So we never really know in advance what a "similar experiment" is going to be-- and the scientist in us is always looking for the differences, whereas the philosopher is hoping it will be similar, because that was the purpose of developing science in the first place.

  26. #56
    Seems that the speed of light is only prohibitive for objects that have mass, im a little confused as to this

    http://weirdsciences.net/category/ph...ysics-physics/

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    You're confused for the usual reason-- we have a science writer communicating a subtle effect that he/she does not understand, and it shows. For example, the statement that this effect cannot send information faster than c because it only works for massless things like light is total bunk-- since light can send information! The reason you can't send information faster than c is because even light can't do it, nor does it happen in this experiment. As near as I can tell, this experiment is like having a train that extends from New York to the city limit of Los Angeles, and having a con man standing on the engine say "I'll bet you a thousand bucks I can get the back of this train to this here city limit in less than one minute." The confident but naive physicist says "I'll take that bet, it's impossible!" The con man wins his bet by simply decoupling all but the front two cars, firing up the engine, and saying, "look, the back of the train is crossing the city limit, pay up." But of course the train is not sending any information faster than c, because decoupling cars does not transmit information.

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    The article aside, it is pretty simple: Mass is the degree to which
    matter resists being accelerated. Matter which strongly resists
    being accelerated has high mass, while matter which only slightly
    resists being accelerated has low mass. Matter which doesn't
    resist being accelerated at all has zero mass. Light, and maybe
    neutrinos, do not resist acceleration and so have zero mass. It is
    not possible to accelerate them. Instead, they always travel at
    a constant speed.

    The article is talking about the speed of a pulse of many photons.
    The pulse is a long thing. It takes time for the pulse to form and
    decay. It is made of a large number of photons. Each individual
    photon in the pulse moves at the usual speed of light for the
    medium it is travelling through. But the researchers made some
    funny arrangement so that once the photons at the beginning of
    the pulse travel all the way through their special vat, they act in
    some way as though the entire pulse had gone through the vat.
    It reminds me of how constructive interference in lens coatings
    makes it possible for more light to get through the lens than
    through an uncoated lens.

    -- Jeff, in Minneapolis
    http://www.FreeMars.org/jeff/

    "I find astronomy very interesting, but I wouldn't if I thought we
    were just going to sit here and look." -- "Van Rijn"

    "The other planets? Well, they just happen to be there, but the
    point of rockets is to explore them!" -- Kai Yeves

  29. 2011-Mar-06, 11:37 AM


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