G.E.R. Lloyd – “Saving the Appearances”

8 September, 2017 - MA Coursework

G.E.R. Lloyd, “Saving the Appearances, Classical Quarterly, n.s. 28 (1978): 202-222.

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In this article Lloyd seeks to dispel the interpretation, most notably put forth by Pierre Duhem for Lloyd’s purposes, but also by Halma and Wasserstein, that ancient Greek astronomy was essentially “instrumentalist” — that “Greek astronomical theories were devices or fictions put forward purely for the sake of calculation elegance with no claim to correspond with physical reality.” Lloyd first casts aspersions on Duhem’s attempt by pointing out that “saving the appearances” stood for many different methodological positions in ancient natural science but that Duhem took it to mean only that which would serve his purpose (the small amount of background research I did on Duhem has him as an advocate for instrumentalism in his own day, revealing his insistence on the essential instrumentalism of ancient Greek astronomy to be a superficial appeal to classical authority). For Duhem, the “appearance saving” of ancient Greek astronomers meant specifically that they produced conclusions to correspond with observations, but since more than one conclusion could make sense of the observations, the preferable conclusion was the most mathematically simple; its correspondence with observable reality was irrelevant. Wasserstein was even more reductive: “The Greek astronomer in formulating his astronomical theories does not make any statements about physical nature at all. His theories are purely geometric fictions. That means that to save the appearances became a purely mathematical task, it was an exercise in geometry, no more, but, of course, also no less.”

Lloyd claims, in response to Duhem et al.’s insistence, to have the “limited” aim “to examine the foundations, and test the applicability” of the essential instrumentality of Greek astronomy. But Lloyd was being bashful his purpose in this paper was, rather, to nullify this thesis. He is more confident in the paper’s conclusion, in which he described Duhem’s understanding of the classical Greek texts on which his general thesis depended as questionable and at times “certifiably incorrect.” While Lloyd grants that the Greeks recognized a distinction between mathematics and physics, they did not advocate for “a mathematical astronomy divorced from physics” or seek “to liberate astronomy from all the physical conditions imposed on it.”

To achieve this, Lloyd singles out the astronomical writings of Proclus Diadochus, “The Successor” to Plato, and his major commentator. Take the question of the epicycles and eccentrics for example. If Proclus were simply grasping for the first elegant explanation of celestial motion, epicycles and eccentrics will serve nicely. But Proclus is not satisfied, not only do they lack Plato’s explicit approval, but Proclus seems to agonize as to whether they are “mere contrivances” or if they “have real existence.” Duhem washes over all of this, committing three hermeneutic transgressions in the process. His treatment of Proclus’s astronomical views is an overgeneralized gloss; he misrepresents Proclus as siding with the instrumental view of epicycles and eccentrics when he actually criticizes both; and Proclus uses realist assumptions to level those criticisms at the theory of epicycles and eccentrics.

Just as Proclus is desperate to honor the authority of Plato (the great mass of his oeuvre is commentaries of Plato’s works), Duhem seems desperate to lend his late-19th, early-20th century instrumentalism an air of ancient erudite authority, so much so that he was willing to contort Proclus into form, with egregious chiropractic consequences.





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