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Schaffer on the Nebular Hypothesis February 6, 2009

Posted by Will Thomas in Schaffer Oeuvre.
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We’re going to be skipping around in the Schaffer bibliography a little bit now in the hopes of approaching his articles in a way that makes the most sense to me.  Today I want to look at “The Nebular Hypothesis and the Science of Progress” from History, Humanity, and Evolution: Essays for John C. Greene, edited by James R. Moore (1989).  This work is fascinating to me for a few reasons.

1850 sketch of the Orion Nebula

1850 illustration of the Orion Nebula by Lord Rosse

First and foremost, it represents Schaffer’s attempt to translate his methodology for studying natural philosophical cosmologies into the era of disciplined science.  Natural philosophical cosmology was not a tightly restrained genre.  While we might say that there were identifiable sub-genres of cosmology that adhered to fairly specific methodologies and cosmological possibilities, the boundaries between these were very porous, and ideas transplanted themselves fairly easily between them.

Schaffer liked to use the term “resource” to describe these ideas.  Certain kinds of philosophical argument became “possible” (though, of course, not necessary) once resources necessary for those arguments—the restorative role of comets, the perfection of God’s creation, the evolutionary cosmology—became available.  Schaffer’s history of natural philosophy is, largely, the history of these resources.  Unlike, say, John Heilbron’s work on electricity, Schaffer never really followed specific natural philosophical arguments, though his work was clearly informed by his awareness and appreciation of the substance of these arguments.

Disciplinary science is notable because of a very conscious process of what I like to call “bracketing”, wherein work takes place within a mental model that safely brackets off the necessity that the results of the work be squared with the claims of other disciplines.  But it is not quite appropriate to say that natural philosophy “ends” with the rise of discipline.  Issues like the interdisciplinary robustness of arguments, and the moral implications of scientific results remained connected to scientific practice.  However, these issues had to be expressed in new ways.

I don’t think historians ever actually got it quite right, though it was a major concern in the late 1980s, I would say, especially, with Crosbie Smith and Norton Wise’s biography of William Thomson, Energy and Empire.  While speculative arguments could no longer mingle freely with more disciplined work, they were addressed all the time: scientists might find certain results “unpalatable” (to use my preferred term), because of their cosmological and moral implications; or they might speculate in public lectures or popular works as to the broader implications of their work.

These concerns are on full display in Schaffer’s treatment of the “nebular hypothesis”, which also engaged with his early concern for evolutionary cosmologies: in the 19th century the nebular hypothesis essentially became the most important evolutionary cosmology (at least until the 20th century’s “big bang”), explaining, as it did, the formation of the whole solar system from nebular matter.

Schaffer is careful to note that any cosmology, and, especially, any cosmogeny (an account of origins) became carefully separated from disciplined astronomy, including the systematic observational study of nebulae, eventually made respectable by William Herschel.  As John Herschel (William’s son) explained, “just as geology could not reach ‘to the creation of the earth’, so astronomy was ‘confessedly incompetent to carry us back to the origin of our system.”  (Schaffer’s quote, Herschel’s sub-quote).

Schaffer explains that the “nebular hypothesis” was not an entity of disciplined astronomy, and it was not the invention of Laplace, but rather a creation of the 1830s and 1840s, drawing on Laplace’s “probabilistic calculations about planetary orbits” [Schaffer offers little explanation as to what this was about; we’d have to look it up elsewhere] and Herschel’s work on nebulae.  It was a resource that made “an appeal to astronomical authority” to support a “science of progress”.

Now, Schaffer’s most important point in the paper is to attempt to figure out how to write a legitimate history of intellectual resources.  As he notes, prior historiography on Darwin, including the work of John Greene, tended to point to cultural “resources”, notably Malthus’ political economy, but also the evolutionary cosmology of the nebular hypothesis, in Darwin’s formulation of his theory; and then speculate as to whether that damaged the “purity” of Darwin’s science.

Schaffer didn’t think this was good method: “Simple homologies prove little.  A more sophisticated approach is necessary to clarify the relations of different disciplinary communities and the interests served by the transpositions of concepts among them.”  The problem of idea and constituency.

Schaffer observes that the nebular hypothesis motivated astronomers of nebulae, notably the astronomer Thomas Romney Robinson, a “Church of Ireland divine”, who was adamantly opposed to the nebular hypothesis on account of its moral/cosmological implications, and sought to use his privileged access to a gargantuan telescope, the “Leviathan of Parsonstown” (which Schaffer would write about in 1998) to show that all nebulae could be resolved into stellar clusters, going so far as to claim that he had resolved the Orion Nebula.  This is a clear example of undisciplined concerns rendering certain conclusions “unpalatable” to disciplined inquiry.

Schaffer concludes the paper by looking at the use of the nebular hypothesis in the rhetoric supporting the British movement for “political economy” in “radical” politics (here primarily meaning expansion of the voting franchise, “Chartism”, and the move toward free trade, especially the repeal of the Corn Laws).  He looks in particular at its use by the Scottish astronomer and political economist John Pringle Nichol.  Here the possibility of developing rational descriptions of social and economic progress were deemed accordant with ideas that the universe itself underwent a progressive evolution.

Schaffer goes into some detail about the “strictures” for the rhetorical use of the nebular hypothesis—the relationship between statistics and political economy vs. the relationship between astronomical observation and astronomy; the necessary avoidance of “atheist materialism” in discussions of humans, etc.  I won’t go into details here.

What I just want to end with is that I think historians of science tend to stumble badly when analyzing public rhetoric, because of the tendency to overstate the importance of their subject matter within the overall scheme of rhetoric in use.  Schaffer, I think, is aware of the difficulties, but I don’t think he entirely escapes them.  He offers us what I believe are overly ambitious phrasings: “an appeal to astronomical authority” and Nichols saw “that the nebular hypothesis was particularly appropriate as a bulwark of his campaign” (my emphasis).

I think Schaffer’s intent to focus on the use of the nebular hypothesis in particular in the rhetoric of political economy decontextualizes it from its primary place within that broader rhetoric.  It is not clear to me that astronomy actually had much authority in public debates, that it could serve as an effective “bulwark”, or that its role was anything but marginal in the history of political economy in the public sphere.  Schaffer should have attempted to clarify its place within that history more effectively.

In natural philosophy, “resources” are important, because they form part of the logical structure of the cosmology.  Rhetoric, which does not operate in the same way, requires a more differentiated vocabulary.  I think Schaffer’s analysis is locally right, but I think he ought to have offered some notion of the rhetorical context surrounding the specific rhetoric of the nebular hypothesis to indicate what was and what was not truly at stake.  The evaluation of significance is at least as important as the recognition of links between internalist ideas and externalist concerns in establishing proper context.

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Comments»

1. NCEDIWE NGOYI - February 11, 2009

according to the question I have asked I am not satisfied. So can you please differentiate for me between nebular and big bang?

2. Will Thomas - February 11, 2009

The nebular hypothesis is the creation of solar systems from the collection of nebular matter (gas, dust…) through gravity. The “big bang” is the creation of the entire universe in an explosive expansion from a single point.


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