The Rise of Modern Science

Backhouse, Chp 4

Leonidas Montes, “Smith and Newton: Some Methodological Issues Concerning General Economic Equilibrium Theory”

There is no single point in time at which “modern science” began. All great thinkers contribute original ideas that grew out of suggestive thoughts or intellectual conundrums raised by earlier thinkers. But the 16^th century witnessed a period of marked advancement in the state of scientific thinking.

Backhouse focuses on two “dominant figures” in his book: Francis Bacon (1561-1626) and René Descartes (1596-1650). The Englishman Bacon published his Novum Organum in 1620. In it he called for a reconstruction of knowledge on the basis of natural history (the detailed, systematic collection of facts about nature) and induction (deriving laws of nature from the facts). Bacon was not the first modern proponent of careful observation of nature, but his ideas drew wide attention.

The Frenchman Descartes elevated reason to the highest level. His methodology differed diametrically from Bacon’s, since “Descartes sought, in the manner of mathematics, to base [knowledge] on a set of simple, self-evident truths.” Descartes believed that, using deductive logic, more complex truths could be derived from the basic (true) premises. Descartes rejected the view that the most comprehensible way to understand the world was as a single organism. Rather, he believed that it should be seen as a mechanical system made up of many parts. Scientists should focus on qualities that could be measured, removing subjectivity from scientific analysis.

Both Bacon and Descartes had immense influence on later generations of scientists. The Royal Society, formed in London in 1662, promoted discussions among English intellectuals interested in scientific investigations. The Society’s most illustrious member in the 18^th century was Isaac Newton. Alexander Pope’s intended epitaph for Newton indicates his stature: Nature and nature’s laws lay hid in night:

God said, Let Newton be! And all was light.

Pope’s verse brings out a point that many commentators on the Enlightenment tend to gloss over: The rejection of authority (the Church or the Bible) in favor of empirical investigations did not mean that all those interested in science rejected God. Newton, for one, did not. Although his Christianity was unorthodox, and was even considered heretical by the Church of England, he believed wholeheartedly in God and spent a great deal of his time thinking and writing about theological issues.

In his masterpiece, Philosophiae Naturalis Principia Mathematica, Newton set forth a system of celestial mechanics that guided astronomers and physicists in their studies until the early decades of the 20^th century. Newton discovered a system of mechanics that under certain conditions – those of a closed system – gives rise to event regularities facilitating the use of mathematics. And the Principia is highly mathematical, making extensive use of differential and integral calculus, which Newton invented. (The German philosopher Leibniz independently invented the calculus at about the same time.) The highly mathematical nature of Newton’s theory has led commentators down to the present to argue that Newton’s methodology was patterned after that of Descartes. And certainly, Newton deduced many important propositions by arguing from his basic principles. However, deductive logic was not the heart of Newton’s system.

Newton’s method was a combination of analysis and synthesis. The analysis part consisted of “experimental philosophy,” in which Newton carefully observed phenomena and deduced propositions from his observations. He then generalized these propositions through induction (reasoning from the specific to the general). Most commentators have allowed “synthesis” – and hence mathematics – to overshadow induction. In fact, although Newton created a mechanical, mathematical system of cosmology, he did not believe that mechanical laws can explain all phenomena of reality. For Newton, “the universe, in its true essence, is not a mechanism, for mechanical laws cannot account for its origin and sustained existence” (Drennon, qtd. in Montes, p. 119). Many scientists after Newton did look at the universe as a mechanical system, and a few continue to do so, as do many atheists. But the mechanical view of the universe flows from Descartes and Leibniz, not from Newton. Modern physicists tend to compare the universe not to a machine but to a thought.

Why does all this matter to us? Because economists have followed in the footsteps of great scientists. As Backhouse states, some 17^th century economists were members of the Royal Society. William Petty (1623-87) studied medicine and taught anatomy and, under Cromwell, surveyed much of Ireland. He also originated Political Arithmetick, a quantitative approach to economic issues. Petty argued, “Instead of using only comparative and superlative words, and intellectual arguments, I have taken the course … to express my self in terms of number, weight or measure; to use only arguments of sense, and to consider only such causes, as have visible foundations in nature.” Petty might be thought of as the grandfather of national income accounting.

Much later, some well-known economists patterned their system after what they presumed to be Newton’s. Leon Walras, who invented general equilibrium analysis, saw himself as modeling the economy in a Cartesian or Newtonian manner. Modern neoclassical economists suppose themselves to be following Newton’s approach in deriving models from a few generally accepted principles, deducing outcomes – with the help of mathematics – and then using data to see if their models accord with reality. Most economists believe that this was the approach taken by Adam Smith. Only it wasn’t. Smith’s actual approach may have been similar to Newton’s, but Newton’s wasn’t what most people think it was. So we can’t look at Smith through modern neoclassical eyes without distorting his message.