In a recent post I explained some of the history behind evolutionary theories of the solar system. As with biological evolution, this cosmological evolution was declared to be a fact based on observed patterns, even though very little was understood about how the solar system could actually spontaneously arise.
The claim that the evolution of the solar system is a fact was metaphysically loaded and it hinged on the claim that there was a single mechanical cause. But as with biological evolution, this cosmological evolution is repeatedly contradicted by empirical science, and so a great variety of patches were required to save the theory. The specter of a single cause was lost a long time ago.
But those past failures are conveniently forgotten and, again as with biological evolution, today there is a tremendous flexibility of explanation for the origin of the solar system. In my post I listed several just-so stories used today to patch the theory. There are many which I did not mention and one set of patches deals with isotope heterogeneities. As a new paper explains, both (i) “exotic” material and (ii) complex isotope-selective chemistries have been used to explain the heterogeneities:
Thus, the discovery that high-temperature minerals in carbonaceous chondrite meteorites are enriched preferentially in 16O compared to 17O and 18O relative to the abundances in terrestrial samples was considered evidence for the presence of exotic material that escaped thorough mixing and thereby retained a memory of its distinct nucleosynthetic history. Later findings of the widespread nature of very large oxygen isotopic heterogeneities among meteoritic materials and the lack of correlation of these oxygen isotopic compositions with those of presolar components led to various proposals that the oxygen isotopic anomalies were instead generated by complex isotope-selective chemistry within a homogeneous nebula.
New findings from the Genesis spacecraft reveal even more “extreme” nitrogen isotope heterogeneities, as well as oxygen isotope heterogeneities, which I cited as yet more challenging observations for the current theory of solar system evolution. In response to this an evolutionist disagreed:
the ratio of the isotopes measured by Genesis was expected to be different from the average for the solar nebula. The effect was predicted by Clayton in a 2002 paper (Reference 6) and observed in other molecular clouds. The new data present no problem for the solar nebula model, they confirm it!
Sure the isotope heterogeneities were expected. Heterogeneities had already been observed. What the professor does not mention in his comment is that the referenced paper predicted oxygen isotope heterogeneities using a just-so story (isotope-selective self-shielding during ultraviolet photolysis of carbon monoxide), and that heterogeneities were already known to exist.
In other words, like the claim that retrograde motion confirms geocentrism, this claim that the observed oxygen isotope heterogeneities confirm the solar system evolution model is ridiculous. The solar system evolution model was highly augmented with a detailed patch designed to explain the heterogeneities (complex isotope-selective chemistries), and now new observations of oxygen isotope heterogeneities are claimed as a confirmation.
Sure this is a valid prediction, but hardly of the significance the professor claims. This is yet another example of how evolutionary thinking harms science by introducing fallacious reasoning used to protect evolution.
Retrograde motion is hardly a confirmation of geocentrism. It is, rather, contradictory evidence that needed to be explained away. But once those epicycles were added, the geocentric model did indeed predict the retrograde motion. So for a desperate geocentrist apologist, the backward motion of Mars does indeed become a confirmed prediction. This is an abuse of science.
ReplyDeleteHardly an abuse of science; it was perfectly normal science in its day, given the blanket acceptance of geocentrism and the technology then available to study the heavens.
Consider how tenaciously the Church - in those days - defended the geocentric view.
Cornelius Hunter: Retrograde motion is hardly a confirmation of geocentrism.
ReplyDeleteThat's because retrograde motion is not *entailed* in the hypothesis of geocentrism.
Cornelius Hunter: In other words, like the claim that retrograde motion confirms geocentrism, this claim that the observed oxygen isotope heterogeneities confirm the solar system evolution model is ridiculous.
No. The radiative sorting by isotope is reasonably *entailed* in the hypothesis that the Solar System coalesced from a nebula.
Cornelius's argument boils down to two lines:
ReplyDeleteSure the isotope heterogeneities were expected. Heterogeneities had already been observed. What the professor does not mention in his comment is that the referenced paper predicted oxygen isotope heterogeneities using a just-so story (isotope-selective self-shielding during ultraviolet photolysis of carbon monoxide), and that heterogeneities were already known to exist.
Cornelius merely asserts that Clayton's 2002 model [1] was "a just-so story" and offers no explanation. I find such an argument utterly unconvincing.
Self-shielding is based on simple physics: positions of spectral lines in molecules depend on the atomic masses, so the rate of ionization by thermal radiation varies by the isotope. The effect is particularly important in the ultraviolet, where the intensity of the solar radiation drops quickly as the frequency grows. Spectroscopic studies indicate that the effect is present in molecular clouds [2]. Clayton's idea was to extend it to the solar system. His prediction is furthermore falsifiable. The Genesis mission could have ruled it out. Instead, it ruled out competing models.
This is how science is supposed to work.
[1] R. N. Clayton, "Solar System: Self-shielding in the solar nebula," Nature 415, 860 (2002). doi:10.1038/415860b
[2] J. Bally and W. D. Langer, "Isotope-selective photodestruction of carbon monoxide," Ap. J. 255, 143 (1982). doi:10.1086/159812.
Is there anyway a mailing list could be created to inform interested parties when a new post has been created? It can be weeks between posts. It would save a lot of time for the regular bloggers who visit this site.
ReplyDelete.
Off-Topic
ReplyDeletePeter: Is there anyway a mailing list could be created to inform interested parties when a new post has been created?
When you are logged in, there should be a "Subscribe by email" link below the comment field.
What Cornelius is attempting to do here is propagate two myths. Both of which are designed to assert that explanations for phenomena he thinks were directly caused by God cannot be explained.
ReplyDeleteFirst, Cornelius want's you to think is that, science hasn't changed since the time of the Galileo affair. This is a blatant misrepresentation. Galileo was one of many who had significant impact on the scientific method. What Galieleo brought to the table was the idea that the universe could be understood in universal, mathematically formulated laws, and that reliable knowledge of these laws was accessible to human beings if they applied his method of mathematical formulation and systematic experimental testing. This was in contrast to divine revelation, the study of God's creation, etc. In fact, it's said that Galileo himself was the father of modern science.
Second, Cornelius want's you to think that, at the time of the Galileo affair, we had no objective way of discerning between geocentrism and Heliocentrism since observations alone be said to to support both theories. Again, this is yet another misrepresentation, as there is such a thing as a bad explanation and objective ways to identify them. For example…
CH: What if an astronomer told you that the retrograde motion of the planet Mars is confirmation of geocentrism?
Where to start? Again, Cornelius is operating under a justifcationalist framework, which he smuggles into his argument and implicitly shares with his target audience. As such, to say that observations "confirms" anything is a form of equivocation. Given that he's yet to address this, despite multiple requests for clarification, it seems that this represents a intentionally dishonest tactic on his part. Again the problem of induction prevents the specific sort of justification that he's referring to. Truth exists, not just in the form that Cornelius is referring to and appealing to.
CH: Retrograde motion is one of the reasons that geocentrism needed to be patched with those dozens and dozens of epicycles. Retrograde motion is hardly a confirmation of geocentrism. It is, rather, contradictory evidence that needed to be explained away.
This is a highly simplistic view, which represents merely the tip of the iceberg. What he's referring to is Occam's razor. However, this too has problems as one could just as easily claim that Galileo introduced an unnecessary component by suggesting the earth moved, which we do not feel or observe at face value. It contradicts intuition, scripture, etc. Again, Cornelius wants to muddy the water to ensure phenomena he thinks was directly caused by God cannot be explained.
However, It's not that geocentrism was a bad explanation merely do to observations of retrograde motion. Instead, it was a bad explanation due to the fact that it failed to explain retrograde motion.
What do I mean by this?
At the time, Heliocentrism was the accepted means of predicting the night's sky. If you asked why a planetary conjunction occurred on such-and-such a date, or why a planet backtracked across the sky in a loop of a particular shape, the answer would always be ‘because that is how it would look if the heliocentric theory were true’. In fact, the Inquisition did not object to using Heliocentrism to predict the nights sky. It's objection was specific to claiming Heliocentrism was an explanation for the night sky. It's for this that Galileo was put on trial.
In other words, one could not understand geocentrism without first understanding Heliocentrism. It's a theory that can only be understood in terms of a different theory that it contradicts, yet faithfully mimics. As such, we can say geocentrism is a convoluted elaboration of Heliocentrism. We can rule it out without experimental testing because it's a bad explanation.
Of course, Cornelius conveniently leaves these details out of his argument as they do not suit his agenda.
Just to clarify, I'm NOT suggesting we could have ruled geocentrism out as an infinite number of possible states-of-affiars without experimental testing. However, I am suggesting we could have ruled it out as an explanation for the night sky.
ReplyDeleteThis is due to the fact that it objectively failed to meet the definition of an explanation.