[SydPhil] HPS RESEARCH SEMINAR SERIES
debbie.castle at sydney.edu.au
Tue Oct 16 09:55:16 AEDT 2012
Next week's presentation in the 2012 HPS Research Seminar Series will be:
GRANT FISHER (KOREA ADVANCED INSTITUTE OF SCIENCE AND TECHNOLOGY)
"Passions and punctilios: Models, methods, and controversies in late twentieth century physical organic chemistry".
It has been a source of frustration to chemists that some of the organic reactions most important to the productive synthesis of new compounds have been the most difficult to study. Since the early twentieth century, chemists struggled to account for intra-molecular rearrangements (reactions taking place within a molecule resulting in a fundamental change to the underlying carbon skeleton) and cycloaddition reactions including the Diels-Alder reaction. While it was possible to chemically analyse reactants and products, it was difficult to figure out what went on "in the middle" as reactants converted to products. By the late 1960's, a relatively simple qualitative quantum chemical approach - orbital symmetry modeling - offered a mechanism for "pericyclic reactions" (as they came to be called) and a means to predict their outcomes. In spite of this apparent breakthrough, orbital symmetry models were criticised for their lack of theoretical and empirical support. While the models were defended on pragmatic grounds, a deeper controversy soon emerged. Applying quantum mechanics to the study of molecular reactions is challenging because of the complexity of the target systems. Theoretical chemists have typically drawn on two kinds of approximation method to predict the properties of organic reactions. One might suppose that whatever method of approximation is employed, the quantitative results might differ in terms of their precision but not in terms of their consistency. However different methods gave different answers, and this led some chemists to infer that the results were merely artifacts of the approximation methods. Since the source of inconsistency was poorly understood and theoreticians' methodological arguments could not resolve the controversy, an independent standard was sought to sort artifacts from legitimate results. In spite of their apparent drawbacks, qualitative orbital symmetry models were thrust into this role. Drawing on the normative claims made by the originators of orbital symmetry models, this paper investigates the interplay of qualitative models and quantitative approximation methods during a controversy that gripped theoretical physical organic chemistry in the late twentieth century. It is argued that intelligibility is an epistemic desideratum for models.
WHEN: OCT 22ND 6PM - 8PM
WHERE: SCIENCE MEETING ROOM 450 CARSLAW BUILDING CAMPERDOWN CAMPUS.
ALL ARE VERY WELCOME
Debbie Castle | Administration Officer
Office Hours: 9am - 4.30pm: Monday, Tuesday & Wednesday
Unit for History and Philosophy of Science
Faculty of Science
THE UNIVERSITY OF SYDNEY
Rm No. 441 Carslaw Building, F07 | The University of Sydney | NSW | 2006
T +61 2 9351 4226
e debbie.castle at sydney.edu.au<mailto:debbie.castle at sydney.edu.au> | W http://sydney.edu.au/hps
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