I have selected this quotation for special attention because we can identify from it and the surrounding passages in the Lectures on Rhetoric and Belles Lettres (Smith [1762–63] Reference Smith and Bryce1983; LRBL) key elements of Adam Smith’s philosophy of science. At the same time the quotation provides an example of Smith’s own arresting use of rhetoric.

The quotation arises from Smith’s exploration of the philosophy of science in terms of didactic rhetoric. Smith’s theory of rhetoric emphasized its role in persuasion, departing from the conventional emphasis on style. Persuasion by argument was central to an epistemology (in the Scottish Enlightenment tradition), which was skeptical about the scope for establishing absolute truth.

Smith’s philosophy of science was set out more fully in relation to his theory of rhetoric in the essay “A History of Astronomy” (Smith [1795] Reference Smith and Wightman1980). This essay was designed as an illustration of Smith’s theory of human nature with its emphasis on the role of the imagination. It provided a psychological understanding of how different theories are developed, accepted, and then overturned in light of recognition of a disparity with experience that has become undeniable and/or a more appealing explanation of experience.

The quotation above refers to the success enjoyed by René Descartes (Reference Descartes1644) in persuading the “Learned in Europe” to accept his vortex theory of planetary motion. But this theory later foundered for lack of empirical support; indeed it was a purely deductivist theory without empirical input. As Smith ([1795] Reference Smith and Wightman1980, IV, p. 66) put it, Descartes “had never himself observed the Heavens with any particular application.” This was why Smith depicted it as a “Romance” with perhaps no “word of truth.” Yet it was an “entertaining Romance,” its psychological appeal ensuring its long-running success.

Smith ([1762–63] Reference Smith and Bryce1983; LRBL ii.133) identified the success of Descartes’s astronomical theory with the esthetic appeal of its systemic nature, explaining apparently disconnected phenomena by deducing them from “principles known or proved in the beginning, from whence we account for the severall Phenomena, connecting all together by the same Chain.” Smith associated this systems method also with Isaac Newton. But principles, for Descartes, were a priori and thus axiomatic. Newton’s experimental method was founded instead on observation such that the principles so derived were provisional in the face of structural differences in context.

This latter approach to system characterized Smith’s economics, where the experimental evidence was derived from different historical accounts of a range of contexts. The provisional principles so derived, such as the division of labor, then provided a starting point for enquiry into particular circumstances rather than acting as an analytical constraint. Attention would thus be paid to structural differences between contexts rather than striving for universal accounts, with the scope of analysis extending more widely than strictly economic considerations. It was in understanding the divergence of particular contexts from the analytical starting point that theory was more fully developed.

Smith’s theoretical system built on the principle of the division of labor has evidently been highly persuasive, satisfying the psychological requirement for a theory to connect the various processes at work in a socio-economic system. But the Wealth of Nations (Smith [1776] Reference Smith, Campbell and Skinner1976) has been interpreted in substantially different ways and we can look to Smith’s theory of rhetoric for a possible explanation. The interpretations fall roughly into the closed-system general equilibrium reading of mainstream theory and the open-systems readings more evident in Smith scholarship.Footnote ¹ Both are systems readings but with different types of system.

An open-systems reading can take account of the evolution of socio-economic systems and the complex sociality of the individual, connecting with Smith’s (and the reader’s) understanding of real circumstances. This appealing characteristic may be offset by an esthetic challenge that may be posed by complex and contextualized structuralist theorizing using a range of methods. In contrast, the mathematical formalization of the general equilibrium reading has the esthetic appeal of internal clarity, fixity of meaning, and apparently universal application. However, this appeal is countered by the psychological discomfort arising from the evident conflicts between theory and real experience; the truth of the general equilibrium axioms is contestable as being neither “known or proved from the beginning.”

Like Descartes’s theory of planetary motion in astronomy, the general equilibrium approach has held sway for a long time in economics but has come under increasing challenge. Would it be fanciful to think that Smith might have concluded that general equilibrium theory “does not perhaps contain a word of truth” and might be regarded as “one of the most entertaining Romances that has ever been wrote”?