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Thread: Is scientific method obvious?

  1. #91
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    Quote Originally Posted by ngc3314 View Post
    An issue that I only recently was brought to appreciate about the geocentric-heliocentric debate was that some people were trying to measure the apparent sizes of stars (not yet having the optics to understand that the naked-eye, or for that matter telescopic, disks of stars are optical rather than physical) and pointed out that stars far enough away to not show obvious parallax would have had to be so large as to be nothing at all like the Sun. I may have linked it before, but a very detailed historical discussion, by a historian of science, provided in The Great Ptolemaic Smackdown (stay for all 9 parts, it's worth it). Short form: it was way more complicated, more people were important at the time, and what we like to present as the Cartoon Network thread of discovery wasn't at all so obvious at the time.
    Another great point!

    But this would not be something the early Greeks would have considered, right? We are jumping back and forth between Aristotle and Copernicus/Galileo.

    [The link does explain it nicely, btw, but I think they are selling Tycho a bit short (pun intended) on his resolution. It states he could achieve "errors as small as the width of a quarter seen from a football field away." That quarter represents about 1 arcminute (typical resolution of the eye), but Tycho, for some key stars cut that in half -- hence 1 bit; 1/2 a quarter; 12-1/2 cents, a better than average pun, at least for me. He did this by using multiple observers and averaging(?) their data.]
    Last edited by George; 2017-Oct-02 at 07:42 PM.
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  2. #92
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    Quote Originally Posted by Hornblower View Post
    I would not call the stars not being suns the centerpiece of the geocentric model. I would call Earth the centerpiece, with the idea that it is stationary being a reasonable common sense default at the time. The fixed stars were peripheral, and their lack of observable parallax reinforced the geocentric line of thought.
    I can't agree. Aristarchus had already laid out a perfectly plausible heliocentric model. It was the stars that defeated him, not the Earth.
    The idea that God would not have wasted the space needed to place the stars far enough away to make the parallax from a moving Earth unobservable was a belief that was not supported by observational testing, and thus was not scientific by our present standard of scientific method. However, some critics of the moving Earth model thought they had a valid test.
    Yes, it is positively mind blowing how far away the stars need to be if they are suns. I can easily see how many people would have taken it as a good "assumption" that stars can't be that far away. But as I say, that's the wrong way to use assumptions in science, and its track record shows that clearly.

  3. #93
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    Quote Originally Posted by ngc3314 View Post
    An issue that I only recently was brought to appreciate about the geocentric-heliocentric debate was that some people were trying to measure the apparent sizes of stars (not yet having the optics to understand that the naked-eye, or for that matter telescopic, disks of stars are optical rather than physical) and pointed out that stars far enough away to not show obvious parallax would have had to be so large as to be nothing at all like the Sun. I may have linked it before, but a very detailed historical discussion, by a historian of science, provided in The Great Ptolemaic Smackdown (stay for all 9 parts, it's worth it). Short form: it was way more complicated, more people were important at the time, and what we like to present as the Cartoon Network thread of discovery wasn't at all so obvious at the time.
    You mean the debate of the 1600s, not the debate in Aristarchus' time, correct? But yes, we always tend to oversimplify the historical perspective, such as when we say Einstein's photoelectric effect experiment showed that light was made of photons, when in fact it only showed that light exchanged energy with electrons as quanta (which could have happened in a wave model of light if the electron energies were quantized, which they are!). The actual historical debate is usually much more nuanced, so it's nice to hear the full story when we can!

  4. #94
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    Quote Originally Posted by Ken G
    I can't agree. Aristarchus had already laid out a perfectly plausible heliocentric model. It was the stars that defeated him, not the Earth.
    I am confused by this. I stated that the stars provided arguments against a heliocentric model, and you appear to be concurring with that. What did I say that you disagree with?

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    Quote Originally Posted by Hornblower View Post
    I am confused by this. I stated that the stars provided arguments against a heliocentric model, and you appear to be concurring with that. What did I say that you disagree with?
    I disagreed with how you downplayed the importance of the stars, calling them "peripheral." I think had there been no visible stars in the night sky, retrograde motion of the planets would have made the heliocentric model seem inevitable. But when Aristarchus suggested just that, the stars were there to shout him down. Only it turned out to be a whisper-- coming from as far away as it did!

    The example stemmed from the importance of understanding how to use, and how not to use, assumptions in science, which is one of the "not obvious" aspects of the scientific method-- given how often it is violated. Assumptions, like that the stars cannot be incredibly far away, are not to be used as things we hold to be true, the way we hold axioms to be true in mathematics. Instead, they are to be remembered, and tested when it becomes technologically possible, they are just not the top priority to test at the moment. In particular, all assumptions should be explicit, like "if the stars are not incredibly far away...." or "if the universe is not fundamentally dynamical..." or "if there is no source of energy in the Sun nor process to assist heat transport within the Earth..." etc. Think how much less egg-in-face individual scientists, or generations of scientists, would have had if they had been willing to use a few essential extra words, words that are crucial elements of the scientific method done right. The question then is, where is this not happening today, which will result in egg in the face of our generation?
    Last edited by Ken G; 2017-Oct-02 at 11:39 PM.

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    I stand by my previous remarks in which I consider the lunar phase and analemma issues to be analogous, because as I see it they both involve misunderstanding or lack of understanding of the geometry in question. The only fundamental difference I see is the degree of difficulty in demonstrating a suitable test. The lunar phase case is far and away the easier one, but I have seen enough people of at least average overall intelligence have trouble with space/position relationships that I would not conclude that it should be obvious to someone in that category who has no occupational motive to test it.

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    Quote Originally Posted by Ken G View Post
    I disagreed with how you downplayed the importance of the stars, calling them "peripheral." I think had there been no visible stars in the night sky, retrograde motion of the planets would have made the heliocentric model seem inevitable.
    But stars' distances were less important of the false assumptions. The biggest false assumption I think would be Aristotle's four elements of earth, water, air, fire (aether came later I think). This model argues for the center of the Earth to physically be the center of the universe, where all substance falls toward this center and finds its natural place in the order stated. So the stars are but specs in the ointment (peripheral). Ptolemy addressed retrograde adequately, though the heliocentric model was simpler, yet only on paper. The elemental model, things flying off a rotating earth, etc. would add complexity to any accurate model until the false assumptions were addressed, which I think is your appropriate point.

    But when Aristarchus suggested just that, the stars were there to shout him down. Only it turned out to be a whisper-- coming from as far away as it did!
    But the weight of Aristotle likely pressed hard against opponents. The elements, again, playing a key role. No object is found to fall toward the Sun since the Sun, per Aristotle and others, is not the center. And other assumptions would need debunked as well. The lack of parallax was a quick debunk of an interesting model (heliocentric) but not one that explained all the consequences of moving the center from Earth's core to anywhere else.
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    Quote Originally Posted by Hornblower View Post
    I stand by my previous remarks in which I consider the lunar phase and analemma issues to be analogous, because as I see it they both involve misunderstanding or lack of understanding of the geometry in question.
    I'm sorry, I just don't see how you can possibly equate something as subtle and difficult to picture as the analemma on the same terms as something as obvious and easy to see as the fact that the shadow of the Earth does not fall on a crescent Moon seen close to the Sun. That's like saying that understanding 2+2=4 is analogous to understanding that the derivative of x2 is 2x!
    The only fundamental difference I see is the degree of difficulty in demonstrating a suitable test.
    Yes, quite.

  9. #99
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    Quote Originally Posted by George View Post
    But stars' distances were less important of the false assumptions. The biggest false assumption I think would be Aristotle's four elements of earth, water, air, fire (aether came later I think). This model argues for the center of the Earth to physically be the center of the universe, where all substance falls toward this center and finds its natural place in the order stated. So the stars are but specs in the ointment (peripheral).
    That wasn't an assumption, it was a model, and no doubt it was part of their thinking-- but Aristarchus could still design a heliocentric model, so it's not like the Greek mind simply couldn't get outside that box.

    Ptolemy addressed retrograde adequately, though the heliocentric model was simpler, yet only on paper.
    Yet the Greeks looked for stellar parallax, and had they seen it, they would not have put the stars on little epicycles-- that's the whole reason they were looking for it. The need for epicycles was the contrast between the complex motion of the planets, and the simple motion of the stars. If not for that contrast, which is only a surprise if one thinks the stars are not vastly farther than the planets, Ptolemy's model doesn't fly.

  10. #100
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    Quote Originally Posted by Ken G View Post
    I disagreed with how you downplayed the importance of the stars, calling them "peripheral." I think had there been no visible stars in the night sky, retrograde motion of the planets would have made the heliocentric model seem inevitable. But when Aristarchus suggested just that, the stars were there to shout him down. Only it turned out to be a whisper-- coming from as far away as it did!

    The example stemmed from the importance of understanding how to use, and how not to use, assumptions in science, which is one of the "not obvious" aspects of the scientific method-- given how often it is violated. Assumptions, like that the stars cannot be incredibly far away, are not to be used as things we hold to be true, the way we hold axioms to be true in mathematics. Instead, they are to be remembered, and tested when it becomes technologically possible, they are just not the top priority to test at the moment. In particular, all assumptions should be explicit, like "if the stars are not incredibly far away...." or "if the universe is not fundamentally dynamical..." or "if there is no source of energy in the Sun nor process to assist heat transport within the Earth..." etc. Think how much less egg-in-face individual scientists, or generations of scientists, would have had if they had been willing to use a few essential extra words, words that are crucial elements of the scientific method done right. The question then is, where is this not happening today, which will result in egg in the face of our generation?
    It appears to me that your view of the history of this topic is rather different from mine. For as long as I can remember it has been my understanding that the classical Greek thinkers had what they thought were compelling arguments against a moving Earth model, and that the lack of observable stellar parallax was just another argument against it, along with more down-to-Earth arguments. By this I mean lack of any sensation of rapid motion or violent wind, or the way dropped objects were not left behind. Apparently Aristarchus did not have these objections, but plenty of others did, and I would not jump to any conclusion that an absence of fixed stars would necessarily have made a quick difference in how long it would have taken for a Sun-centered model to gain acceptance in that environment.

  11. #101
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    Quote Originally Posted by Ken G View Post
    That wasn't an assumption, it was a model, and no doubt it was part of their thinking--
    Fair enough, the model did have objective evidence but it was heavily laced with assumption, which I think is the crux of your points about assumptions.

    but Aristarchus could still design a heliocentric model, so it's not like the Greek mind simply couldn't get outside that box.
    Aristarchus stands apart in both thought and location. I suspect that the Ionians had a distinct advantage of being located between two cultures, especially given the religious implications. There was mutual exclusivity between the Persian gods and the Greek gods, so perhaps this allowed greater freedom of thought.

    The importance of parallax (its lack) for Aristarchus should be in agreement with your argument, and perhaps this became true for Archimedes. I think, however, Hornblower and I are considering all the Greek thinking that has other, more earthly arguments against it. So we are all correct if we parse the characters.

    Yet the Greeks looked for stellar parallax, and had they seen it, they would not have put the stars on little epicycles-- that's the whole reason they were looking for it. The need for epicycles was the contrast between the complex motion of the planets, and the simple motion of the stars. If not for that contrast, which is only a surprise if one thinks the stars are not vastly farther than the planets, Ptolemy's model doesn't fly.
    But don't forget the Tychonic model. Stellar parallax, had they seen it, would be a nice fit with the Tychonic model leaving Dante to write as he did.

    When Galileo debunked the Aristotle/Ptolemy/Thomist model with Venus, the Jesuits were surprisingly quick to agree but they had Tycho's model on their only slightly dusty shelf to replace Ptolemy.
    Last edited by George; 2017-Oct-04 at 05:27 PM.
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    Quote Originally Posted by profloater View Post
    I meet people regularly who do not know about the 28 day cycle, they just never thought about it and if they were ever taught it slipped away as irrelevant stuff. City dwellers do not catch sight of the moon often. For them indeed it is trivia, like which side was (pick a country) on during WW2. And to understand scientific method, ? Just another irrelevance. Something somebody else does when they don't have to work. Am I getting bitter? I now have to explain to professional electricians what a relay is and why inductive loads trip RCDs (GFCIs) not just science but technology is getting remote from the majority, it'S not good. Is it?
    My brother works for NASA/Ames. Server cluster expert. He was stunned to see professional electricians who couldn't quote Ohm's Law!

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  13. #103
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    Quote Originally Posted by Hornblower View Post
    It appears to me that your view of the history of this topic is rather different from mine. For as long as I can remember it has been my understanding that the classical Greek thinkers had what they thought were compelling arguments against a moving Earth model, and that the lack of observable stellar parallax was just another argument against it, along with more down-to-Earth arguments.
    My point was that Aristarchus was a "classical Greek thinker", and he suggested the heliocentric model to explain retrograde motion. Had there been retrograde motion in stars (if they were closer), that would have been the end of it, Aristarchus would certainly have prevailed. Had there been no stars to see, the issue is less clear, but it certainly seems to me his description of retrograde motion would have been compelling, as it was to Copernicus so many years later. But when there were observations of stars, and they did not show parallax, that was the killing blow to Aristarchus' model. He really had no answer, except that the stars must be absurdly far away. The Greeks had made the key assumption that this was not plausible, but had they simply said "assuming the stars cannot be that far away, we must favor the geocentric model until we have the capacity to test the distance to the stars or the other differences between the geocentric and heliocentric predictions", then they would have been doing good science and would not have been considered wrong-- because they would not have been wrong. That's my whole point-- the way to do science without being wrong.
    By this I mean lack of any sensation of rapid motion or violent wind, or the way dropped objects were not left behind.
    The Greeks had a view where the atmosphere would not cling to the Earth if the Earth were moving, but they were not idiots-- they knew that if you jump up in a chariot, you come down in the chariot. So their issue was more with a picture that air sat atop water and earth, and it was a model that did not sit well with a moving Earth but also could not point to much in the way of predictive power. Really it was more philosophy than science, and science was still coming of age back then, so perhaps it's unfair for me to hold them to a strictly scientific standard.
    Apparently Aristarchus did not have these objections, but plenty of others did, and I would not jump to any conclusion that an absence of fixed stars would necessarily have made a quick difference in how long it would have taken for a Sun-centered model to gain acceptance in that environment.
    I agree that we do not know what they would have concluded in a hypothetical scenario where there were no stars to see, but it certainly would have removed Aristarchus' key problem, though there still would have been the failure to recognize the difference between air resistance and no air resistance. Still, my point here is that the Greeks did make the key assumption that the stars were not very far away, and had they explicitly stated that assumption, they would not have been wrong, they would have merely been prioritizing their test items.
    Last edited by Ken G; 2017-Oct-04 at 10:18 PM.

  14. #104
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    Quote Originally Posted by George View Post
    Aristarchus stands apart in both thought and location. I suspect that the Ionians had a distinct advantage of being located between two cultures, especially given the religious implications. There was mutual exclusivity between the Persian gods and the Greek gods, so perhaps this allowed greater freedom of thought.
    That's an interesting point, and speaks to the overlap between science, religion, and philosophy that was still widespread in that age. It has taken science a long time to fully emerge as a separate mode of inquiry from those others.
    The importance of parallax (its lack) for Aristarchus should be in agreement with your argument, and perhaps this became true for Archimedes. I think, however, Hornblower and I are considering all the Greek thinking that has other, more earthly arguments against it. So we are all correct if we parse the characters.
    It almost requires an exhaustive historical search to properly weight the factors, and no doubt it depends on the individual Greeks and how influenced they were by various philosophies and religions of the day.
    But don't forget the Tychonic model. Stellar parallax, had they seen it, would be a nice fit with the Tychonic model leaving Dante to write as he did.
    Actually, I don't bother to distinguish the Tychonic model from the Copernican one, because to me it makes no difference at all if the Earth is regarded as moving-- that was never the issue. Indeed, today we can see it is purely a question of coordinate system! But what did matter then, and matters now, is the revolutionary difference between imagining that Earth and the Sun are vastly different from the other planets and the stars, versus imagining that the Earth is a planet, and the Sun is a star. Those were always the real stakes in that debate! Eppur si muove was a red herring from the start.

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