Stars are not fire - it can burn without consuming oxygen or any other oxidants. “Nuclear fire” is a flowery word to describe nuclear fusion. But I wasn’t referring to that particular error.
What I was referring to is that:
The color of a star is determined by the peak of the envelope of the photon distribution, not the chemical composition. In particular, stars of the same color can have different stellar spectrum, i.e. the result of stellar spectroscopy is not a function of the color of the star. If this is the supposed foundational contribution to stellar spectroscopy by John Philoponus, then I regret to tell you that this is not a foundation in stellar spectroscopy at all.
Of course they’re not fire in the sense of necessarily consuming oxidants. But “fires” is an appropriate layman’s description in the same way that “nuclear fire” is a legitimate “flowery word to describe nuclear fusion”. Remember you claimed none of those statements were right “at all”. If your meaning wasn’t so totally absolute, it would have been better to avoid such absolute language.
This conversation is similar to the previous conversation, when you denied the connection between medieval discussions of impetus and the development of inertia theory on the basis that medieval impetus wasn’t the same as the modern understanding of inertia. I think what you’re doing is like saying “It’s totally wrong to speak of the heat of the fire; there’s no such thing as the heat of a fire, but there is such a thing as the thermal results of oxidation”, or “It’s totally wrong to speak of the colors of stars; they don’t have colors at all, they emit electro-magnetic radiation at different wavelengths”.
…that it is not right at all to say that different chemicals burn with different colors, for a start.
I think you’re too fixated on the “fire” business, or that I said “not right at all” in the beginning of my sentence. This part, for example,
is correct. Perhaps you want to engage the substance of the actual argument instead of delving into literarism.
As I said, the error that I was referring to is the idea that the color of stars is important at all in stellar spectroscopy. This, as I understand from your explanation, is Philoponus’ supposed foundational contribution to stellar spectroscopy.
By the way,
I don’t know where you get this. Stars definitely do have colors.
I see it differently. As I pointed out, I think you were far too sweeping and emphatic in your insistence that nothing I said was right at all. That really was part of the substance of your argument. As I noted, I saw the same zeal in the previous conversation, when it seemed extremely important to you that the medieval philosophers made no contribution to modern physics. I have seen this attitude before, among secular and Catholic writers in particular.
I understand that, but I don’t actually find that being said in the commentary I find on stellar spectroscopy (for example, here and here).
Spectroscopy is the study of “what kinds” of light we see from an object. It is a measure of the quantity of each color of light (or more specifically, the amount of each wavelength of light). It is a powerful tool in astronomy. In fact, most of what we know in astronomy is a result of spectroscopy: it can reveal the temperature, velocity and composition of an object as well as be used to infer mass, distance and many other pieces of information.
Like you, when I said A, I mean A, and when I said B, I mean B. I did not say that medieval philosophers made no contribution to modern physics.
As described in your two links, stellar spectroscopy is a measurement of the emission/absorption lines of a star. However, this does not necessarily change the color (especially not the naked-eye color that Philoponus has access to) of a star. Note that the color of a star is given by an integral of the spectrum. Spectroscopy is sensitive to the spectrum itself, not its integral.
I understand. However, this seems to me a stretch, similar to claiming that:
-) The entire field of exoplanet astronomy is founded on the works of Nicholas of Cusa
-) Or that fluid buoyancy is founded on the works of Aristotle
-) Or that modern cosmology is founded on the works of whoever wrote Genesis
The natural sense of this passage is that Philoponus was “a far more formidable contributor to Western intellectual history” than Aquinas, and that the grounds for this judgment are that Philoponus helped lay the foundations of Western science, whereas Aquinas didn’t.
I never denied that Philoponus’s ideas contributed to modern science, nor did I affirm that Aquinas’s ideas were important for modern science. I was questioning only the use of the sweeping phrase “Western intellectual history”; there are many aspects of “Western intellectual history” which have nothing to do with modern science. Aquinas’s discussions of natural law and other areas of political theory contributed to the development of modern political theory, for example, whereas Philoponus (as far as I know) contributed nothing in those areas. And the line of thought running through medieval to Renaissance and Reformation to 17th-century to modern political theory is just as significant a feature of “Western intellectual history” as is the rise of modern science.
It would be nice if you could bring yourself to say, “Well, maybe I was being a bit too sweeping” – but I will not hold my breath waiting for such a statement.
This is not certain. In fact, it seems very likely that even if Philoponus’s works had been entirely lost, the critique of Aristotle would eventually have occurred. This is not to say that Philoponus’s works were not read or had no influence during the formative period of modern science; but that does not prove that they were absolutely necessary to the rise of modern science. Even in the ancient world, Philoponus was not the only critic of Aristotle; and not all critics of Aristotle in the early modern world had read Philoponus. That the history of science would not have been exactly the same without him, I freely grant; that the rise of modern physics might have been delayed somewhat, I also grant; but that it would have been vastly different, or even that modern science would have been vastly delayed (say, by hundreds of years), is not demonstrable. Criticism of Aristotle was “in the air” from the late Medieval period on – and not entirely due to the influence of Philoponus. And there were a lot of very smart cookies living during that period, some of them quite capable of coming up with Philoponus’s criticisms on their own.
(And before you go into an orgy of quotations and links, be aware that I have a great number of the standard sources for the history of science, and have taught university courses on the rise of modern science, so there is no need for you to try to drown me in erudition, as if I have never read anything in the field before. I’m well aware of Philoponus’s contributions, and well aware of the critique of Aristotelianism in the rise of modern science. I’m not opposing your praise of Philoponus or your indication of the defects in Aristotle’s science. I’m merely resisting your tendency to overstatement.)
And the barbarous treatment visited upon the natives of North America by many Protestant invaders from Europe, can they be blamed upon the theology of Thomas Aquinas, too?
In any case, I made no claim that all the influence of Aquinas on Western intellectual history was good; I was merely pointing out that it was powerful, powerful enough that your original statement can be seen as an overstatement. If you still disagree, then fine. I have no more time to spend on what is basically a side remark of yours about Aquinas, a remark you made in response to my announcement of a book on Aquinas and evolution.
Thank you for clearing that up. Your comment about the Big Bang was interesting, expressing precisely the same concern that Lemaitre and some other Catholics had when Lemaitre was first formulating his model. Would it be fair to say you are concerned about the attribution of scientific discoveries and theories to pre-modern scholars? Would it be fair to say you are concerned about the way that pre-modern scientific discoveries (insofar as you recognize them), are represented as contributing to modern science?
My links make statements such as this.
[spectroscopy] is a measure of the quantity of each color of light
[spectroscopy] s a powerful tool in astronomy
most of what we know in astronomy is as a result of spectroscopy
[spectroscopy] can reveal the temperature, velocity, and composition of an object
By analyzing the width of each spectral line in an emission spectrum, both the elements present in a star and their relative abundances can be determined
Consequently I am unsure why you think that the color of a star has no relevance to spectroscopy, unless perhaps you are confining the idea of color strictly to the optical appearance of a star from earth as viewed with the naked eye.
Yes. Emission/absorption lines of what, exactly? Looking at the emission lines on this image, do you see any colors?
Ok I think this is a step forward in agreement, especially given that careful qualifier “necessarily”. So it appears color does have something to do with spectroscopy after all? Given your knowledge of the history of stellar spectroscopy, you will know of the experiments Kirschoff carried out in order to determine composition of the sun’s elements and formulate his three laws of spectroscopy; he put various elements in a bunsen burner and recorded the colors of their flames. If colors are irrelevant to stellar spectroscopy, why was he doing this?
But no one is claiming Philoponus was viewing the same thing we are viewing when we use modern stellar spectroscopy today. It’s about the basic underlying concept which his conclusions shared with modern stellar spectroscopy.
There’s considerably more correspondence in this case than the case of Cusa. In Cusa’s case there’s simply an assumption, on the basis of conjecture. In the case of Philoponus there was a conclusion based on experimental evidence.
Different elements emit different colors when burned/oxidated. If this weren’t true, spectroscopy wouldn’t even be a thing.
Stars are not divine spirits, or ethereal bodies of immaterial immortal matter, or large crystals, but things which burn in some way analogous to the way matter on earth burns.
The colors emitted by stars are related to the elements of which they are composed, in the same way that the colors emitted by elements burned on earth are related to their chemical composition.
In the case of fluid buoyancy, would you object to the statement that Aristotle’s observations on buoyancy laid the foundation for the science of buoyancy? I think it’s possible we’re using the term “foundation” in different ways. I’m only using it to mean “The starting point, an underlying fact or body of facts on which greater and more accurate knowledge of the subject could be built”, not “The formal scientific law or theory which underlies the modern understanding of the subject”.
In the case of Genesis and modern cosmology, I totally agree with you, because despite Philoponus overthrowing Aristotle and Proclus by arguing for the finitude of the universe and its origin in time from a finite point, no one built modern cosmology on this observation, and Lemaitre’s breakthrough conclusion was derived from his application of general relativity, not Genesis 1.
Yes. Exactly as I explained to you. It’s not making a claim that the scope of Aquinas’ contribution was less broad than that of Philoponus. On the contrary, as I’ve already pointed out, I confined Philoponus’ contributions explicitly to one main field; science. I didn’t even rate his commentary on philosophy and theology.
In contrast, I am entirely willing to accept that Aquinas made contributions to a wide range of fields, even though I believe his greatest impact was on theology, and even though I don’t think his actual contributions were of very significant value to humanity as a whole, unlike Philoponus’.
So what? I explicitly confined Philoponus’ contributions to Western intellectual history, as scientific contributions. Nothing else.
I made the point that if we removed Philoponus from history the entire history of science would be different. You responded thus.
Then later.
Thanks!
Eventually, quite likely. In other words, the entire history of science would be different.
This is irrelevant; as I’ve already pointed out, no one said that he was absolutely necessary to the rise of modern science.
But no one said “vastly different” or “vastly delayed”.
Was this before or after your celebrated careers as doctor, astronaut, and ballerina? Oh, weren’t you a fireman too at one point? I’ve lost count of your lengthy list of professional vocations.
No, I attribute them to the evils of Calvinist theology.
The western European Calvinists , who as God’s “chosen” arrived in North America, believed, “If you diligently keep all [the Lord’s] commandments, …the Lord shall out all these nations before you and you shall occupy the territory of nations greater and more powerful than you. Every place where you set the soles of your feet shall be yours” (Deut. 11:22-24). Biblical interpretation rationalized American Manifest Destiny, the ideological propaganda that justified native genocide and empire building by the United States (Acuna 1988; Drinnon 1980; Horsman 1981).
M. Annette James, “American Racism: The Impact on American-Indian Identity and Survival,” in Race , ed. Steven Gregory and Roger Sanjek (Rutgers University Press, 1994), 43
In Puritan New England, the Calvinist doctrine of election was also used by the European colonists to justify racial discrimination against Native Americans. While indigenous people were racialized as “Indians,” enslaved Africans were racialized as “black.” Within this racial hierarchy, Native Americans and African Americans were seen as subhuman. The “white masculine,” exported from Europe, was believed to be the ideal for all humanity.
Grace Ji-Sun Kim, Embracing the Other: The Transformative Spirit of Love (Wm. B. Eerdmans Publishing, 2015), 3
In general, Calvinist theologians accepted slavery as a legitimate human institution, justifying it on the so-called curse of Ham theory, which held that blacks were the offspring of Ham (and his son Canaan), the son of the biblical Noah, who had dishonored his father and thereby drew the curse of God that condemned his offspring to perpetual servitude. Calvinists who spoke out against slavery in the pre-eighteenth Enlightenment days were the exception to the rule.
Johannes Postma, The Dutch in the Atlantic Slave Trade, 1600-1815 (Cambridge University Press, 2008), 11
No; “in other words,” the history of science (minus “entire”) would have been somewhat different.
Writes the man who discourses in authoritative tones in the fields of theology, Biblical scholarship, climate change, evolutionary theory, and now, the history of science.
The link you are using is a simplification for the lay audience. The “quantity of each color of light” is a simplification for the statement that the spectrum is the derivative of color.
Just a quick lesson on stellar spectroscopy: why do you think Betelgeuse is red and Sirius is blue? Because they have different compositions? No! But because Betelgeuse has less effective temperature than Sirius.
This part is correct, because flames of different colors emit in emission that is brighter than their blackbody spectrums
This part is false, because most of the elements in a star spectrum is detected in absorption and the minority that is in emission is nowhere near bright as its blackbody spectrum.
Given this, to me Philoponus’ contribution is as much a conjecture that is not observationaly founded as Nicholas of Cusa’s.
As I have pointed out repeatedly, I never appeal to my own authority or credentials. In contrast, you often appeal to your own authority, and especially your (totally unsubstantiated), credentials. That’s the difference.
I understand it’s a simplification. I still haven’t seen any sources saying that color is irrelevant to stellar spectroscopy because the colors of stars (whether detected by emission or absorption), have no relation to their chemical composition, size, or age.
Yes, sure. But there’s something missing here; a description of what spectroscopy detects. As often as we discuss this, you keep avoiding any connection between spectroscopy and the detection of the elements of which stars are composed. Yet this is what stellar spectroscopy is used to detect.
So the colors of stars, detected by emission or absorption, have no relation to the chemical elements of the stars? It might have helped if you’d answered the questions in my previous post, because it seems you’re still skipping some things, which is why I am not understanding you.
So far what I’m getting is that colors of elements on earth (as detected by spectroscopy), are related to the chemical composition of their elements, but the colors of stars (as detected by spectroscopy), are not related to their chemical makeup. Is that correct? Spectroscopy can differentiate between elements on earth, but spectroscopy can’t differentiate between elements in stars? It can only detect star temperature?
I am not trying to be difficult, I am finding it genuinely hard to follow you. Yes this is certainly due in part to my limited understanding of the topic, but there seems to be something missing. Kirschoff burned chemicals with a bunsen burner, and invented spectroscopy. He then realised he could detect the chemical composition of stars with spectroscopy. Was this a conjecture which was not observationally founded?
One might divide spectra into three categories - black body spectra, absorption spectra, and emission spectra. The colour of stars is predominantly determined by their black body spectra, which depends on their “surface” (photospheric) temperature. Their chemical composition is primarily deduced from absorption spectra - black lines superimposed on the black body spectrum - emission lines are less important in stellar (as opposed to nebular) spectroscopy. What you see from a dropping chemicals into a bunsen burner are a mixture of black body and emission spectra. Perhaps someone did hypothesise that stellar composition could be studied by spectrascopy on the basis of the latter, but if they did they did so using an incorrect model of stars.
Colors are not seen in emission and absorption. Colors is the integral of the spectrum. Does it make sense this far?
This is color:
C = F_R - F_B = \int_R F_\nu d\nu - \int_B F_\nu d\nu
where \nu is the frequency, and R the bandpass, say the bandpass of the color RED, and B the bandpass, say of the color BLUE, and F_\nu the photon flux distribution. This is how your eyes and any telescope for that matter, works when they detect color.
Emission or absorption lines put spikes in the photon distribution, i.e. they change F_\nu. Notice how I can change F_\nu but keep C the same either by, for example, redistributing power in different bandpasses, having absorption in addition to emission, or even just have the emission/absorption spikes being too thin to be experimentally detected.
What Kirschoff did, burning chemicals in bunsen burner, creates an EMISSION line that is much brighter than the blackbody spectrum, thus changing C. That can happen in a variety of situations, in which case the color becomes a sensitive probe of the composition. That does not happen in stars, and color becomes insensitive to the composition. If you don’t understand any of the preceeding discussions, at least understand the bolded portion.
Edit:
I am not avoiding any connection: spectroscopy is used to detect elements. However, spectroscopy is not saying “this star is red so it is made of X” or “this star is blue so it is made of Y”.
I ask you again: why do you think Betelgeuse is red while Sirius is blue? Not because of the composition!
So you’re saying it is possible to detect the chemical composition from the wavelengths of light emitted (or absorbed), by stars. Like this explanation.
The spectra of the Sun and stars exhibited bright and dark lines called Fraunhofer lines. These were shown to be caused by elements emitting or absorbing light at specific wavelengths. Because each element emits or absorbs light only at specific wavelengths, the chemical composition of stars can be determined.
In this way the spectroscope demonstrated that the gases in the Sun and stars are those of common elements such as hydrogen, helium, iron, and calcium, but at temperatures of several thousand degrees. It was found that the average star’s atmosphere consists mostly of hydrogen (87%) and helium (10%), with all other elements making up about 3%. Helium was actually first discovered in the Sun’s spectrum.
Not really. If I look at this spectroscopy image of emissions, I seem to see colors. If colors are not seen in emission, what are those stripes? Are they non-colors? Why are they different for each different element? That would suggest the stripes can be used to differentiate between the elements.
Yes. He did what Philoponus did, only he understood the chemistry and physics behind it. However they both came to the conclusion that different elements emit flames of different colors when burned. This may or may not be spectroscopy, you can let me know.
I assume that by “color” here you mean “the color of the star as detected by the naked eye”, or do you mean “the emission and absorption wavelengths become insenstivie to the composition”?
These lines are not colors, but spikes in the emission SPECTRUM. I said this over and over, color is an integral of the spectrum. What is used to differentiate between the elements is the SPECTRUM, not the color. Spectroscopy measures F_\nu, the SPECTRUM, not the color, whose equation I wrote in my previous post.
Again, I already repeated this several times. This is spectroscopy, what is NOT spectroscopy is claiming that this conclusion can be used in the case of stars, and that the stellar color gives you the chemical composition instead of the temperature.
By color, I mean the integral of the spectrum I even wrote the equation for it in my previous post. I don’t know why I have to keep repeating stuff to you…
This is an accurate summary, and Kirschoff’s conjecture WAS observationally founded. This is a conclusion based on the absorption/emission spikes in the SPECTRUM, not differences in the star’s COLORs.
They are emission spikes in the spectrum. Color is the integral of the spectrum, again I even wrote the equation in my last post…
Edit:
Maybe this will help: Metals change color when they are heated up. For example, in a hot furnace they will turn red. Metals also have absorption/emission lines that is caused by their composition (and impurities) that can be seen only by metallic spetroscopy. But the color of the metal is not sensitive to these absorption/emission lines, but rather the TEMPERATURE.
This is the exact same case with stars.
Person A claims:
Flames change color in a bunsen burner based on their composition
Metal in different temperature furnaces have different colors
Therefore, metal in different furnaces have different compositions
Of course, 3) is wrong. Would you claim that Person A laid the foundation of modern metallic spectroscopy?
