Representation and Explanation

In advocating one more turn after the social turn , Latour called upon his colleagues to reject the modernist dualism of subject and object associated with the problematic of representation and explanation. He also enjoined them to... 

Pseudospin representation and the perturbative estimates of the bond-geminal ESVs. To provide the required explanation, we notice that the effective Hamiltonians for the bond geminals can be represented as a sum of the unperturbed part which, when diagonalized yields invariant, i.e. exactly transferable, values of the ESVs, and of a perturbation responsible for the specificity of electronic structure for different chemical compositions and environments of the bond. 

In polymers, it is always observed that a packet of carriers spreads faster with time than predicted by Eq. (30). Thus, the spatial variance of the packet yields an apparent diffusivily that exceeds the zero-field diffusivity predicted by the Einstein relationship. Further, the pholocurrent transients frequently do not show a region in which the photocurrent is independent of time. As a result, inflection points, indicative of the arrival of the carrier packet at an electrode, can only be observed by plotting the time variance of the photocurrent in double logarithmic representation. The explanation of this behavior, as originally proposed by Scher and Lax (1972, 1973) and Scher and Montroll (1975), is that the carrier mean velocity decreases continuously and the packet spreads anomalously with time, if the time required to establish dynamic equilibrium exceeds the average transit time. Under these conditions, the transport is described as dispersive. There have been many models proposed to describe dispersive transport. Of these, the formalism of Scher and Montroll has been the most widely used. 

You may want to make a more elaborate table in which you write down each law s name, a brief explanation of its meaning, its mathematical representation, and the variable that is kept constant. 

For a likely explanation, we can turn to Larkin and Simon (1987), who viewed results like these in terms of computational efficiency. Larkin and Simon argue that verbal representations and diagrammatic representations may be informationally equivalent but computationally quite different. The use of diagrams to represent problems is preferable to verbal representation, they suggest, because diagrams facilitate the search process and enhance recognition. 

Andrea Woody received a B.A. in chemistry from Princeton and her Ph.D. from the department of history and philosophy of science at the University of Pittsbingh. She is assistant professor of philosophy at the University of Washington. Her current research concerns pragmatic techniques such as model building and alternative forms of representation that scientific communities develop to make abstract theories tractable, investigating how these techniques are relevant to philosophical accounts of explanation, representation, and rational theory change. Quantum chemistry remains a favorite landscape for exploring these issues. 

Notwithstanding these persistent uncertainties, it was certainly an achievement of quantum chemists to have been able to reassess the role of theory in chemistry, to foster a reappraisal of the meaning of experiments, to rethink the role of visual representations, and to accommodate diverse modes of explanation. These, in fact, may have been the reasons behind Lowdin s choice of the title "Quantmn Chemistry— A Scientific Melting Pot" for the meeting organized in 1977 to celebrate both the 500th anniversary of the University of Uppsala and the 50th anniversary of quantum chemistry (Lowdin et al. 1978). 

Fig. 4 Explanation of the fluorescence-quenching effect [2]. — (A) chromatograms of the same quantities of saccharin and dulcin observed under UV 254 light, (B) schematic representation of fluorescence quenching, (C) spectral reflectance curves of saccharin and dulcin.

Treagust, D. F., Chittleborough, G., Mamiala, T. (2003). The role of submicroscopic and symbolic representations in chemical explanations. International Journal of Science Education, 25(11), 1353-1368. 

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