The relationship between physics and economics is still under the cloud of a diehard myth. It is the idea that physics, the hardest science among the natural sciences, had a rather obvious influence on economics, the hardest science among the social sciences, and this happened because both disciplines treat quantity, not quality, and quantity is what can be treated mathematically. There is a grain of truth in the myth – indeed, only those embodying at least a grain of truth survive – but also this one, like every grain, can yield fruit only if it dies. The story needs just to be turned upside down, that is, economics established first a privileged relationship with physics in the Age of Newton, as a result of a shift in the ‘primary theme’ of a long established analogy, the natural-moral analogy, which had been alive since the times of Plato as iatro-political analogy and became instead a mechanico-political analogy as a side effect of the echo of Newton’s work, of its theological and political implications, and of the confrontation between Cartesians and Newtonians. Strangely enough, the main source of inspiration for such transfers from

the body to the mind and from the universe to the polity was a movement of ideas apparently far away from the inspiration of modern science, namely Renaissance philosophy of nature. This was dominated by Neoplatonic themes, and analogy was believed by Renaissance Neoplatonists to be the ruling principle in the universe. Correspondence between the micro and the macro levels, symbolic relationship, and anthropomorphism were the basic features of such theorising on nature. And yet this climate of ideas did not yield only magic, astrology, and alchemy, since, combined with the Platonic belief in a mathematical nature of the universe, it encouraged application of mathematics in both science and pseudo-science. The iatro-political analogy had been ruling from the time of Plato to the

Renaissance, reaching perhaps the Physiocrats and Adam Smith, when he introduces the ‘animal principle’ that restores health to the political body notwithstanding mistaken policies (Smith 1776: iv.ix.14). A paradigm shift from this analogy to a new one was the source of the new physico-social analogy that became the ruling framework. The reasons for this shift are still to be

explored, but the success of the new Galilean approach in a number of fields within natural philosophy was one reason of interest in the new physics. But also within the new paradigm there were alternative blueprints for further developments, roughly marked by the alternative between Cartesianism and Newtonianism. The former, with its basic analogy that equated the universe to a machine such as a clock, suggested paths of inquiry in the field of social and political theory that encouraged artificialism, authoritarian views of political power, ready-made rules for the correct functioning of society. Newtonianism seemed immediately to suggest blueprints for a non-absolutist view of government, and a view of society where the individual and the public interest could be reconciled by other means than direct intervention from political authority. The clock and the scales became analogies embodying two alternative cognitive strategies in facing society. The choice of either of these primary themes reveals the political approach adopted, absolutist or proto-liberal, but also the view of societal laws, an artificialist one or one based on spontaneous order (Mayr 1986).