Human nature, science of, in the 18th century

DOI: 10.4324/9780415249126-DB039-1
Version: v1,  Published online: 1998
Retrieved April 21, 2021, from

Article Summary

Eighteenth-century speculation on human nature is distinguishable by its approach and underlying assumptions. Taking their cue from Francis Bacon and Isaac Newton, many philosophers of the Enlightenment endeavoured to extend the methods of natural science to the moral sciences. Perhaps the most explicit of such endeavours was David Hume’s ambition for a ‘science of man’, but he was not alone. There was a general convergence on the idea that human nature is constant and uniform in its operating principles – that is, its determining motives (passions), its source of knowledge (sense experience) and its mode of operation (association of ideas). By virtue of this constancy human nature was predictable, so that once it was scientifically understood, then social institutions could be designed to effect desired outcomes.

David Hume regarded his proposed ‘science of man’ as fundamental because upon it depended not only logic, morals, criticism and politics but also even mathematics, natural philosophy and natural religion. Hence he believed that if that science is conquered then a relatively easy victory over the others can be expected. We know from Hume’s own Abstract (1740) of the Treatise of Human Nature (1739–40) that he himself thought the most original element was the use made of the principle of the association of ideas. Hume identified three principles of association – resemblance, contiguity and causation (see Hume, D. §2). Starting from the Lockean premise that any inquiry into human nature must rely entirely upon experience, these principles operate uniformly for humans to bind the universe together. Just as there is, accordingly, a general course of nature with respect to the sun and climate, so there is in human actions; and just as there has been great success in the understanding of natural phenomena, so Hume aimed to emulate that success in the moral sciences through adopting its ‘experimental’ procedures. While this was Baconian in provenance (see Bacon, F.), it was Newton’s achievements that were more generally paradigmatic (see Newton, I.).

Newton himself had indicated the appropriateness of the endeavour when in Question 31 (1953: 179) of the Opticks (1730) he remarked that if the analytical method of natural philosophy is perfected then ‘the bounds of moral philosophy will also be enlarged’. Since for Newton the key to natural philosophy lay in mathematics, one characteristic of the eighteenth-century attempt to establish a science of human nature was to subject the phenomena of human nature to quantification. Francis Hutcheson, whom Hume identified as one of his predecessors in the scientific quest, flirted with this when he developed a calculus derived from certain simple axioms whereby M=B × A or the moment of good equals benevolence times ability (see Hutcheson 1725).

Although Hutcheson excised this calculus from later editions of the Inquiry, this quantitative and calculative concern persisted. Jeremy Bentham stated that we are governed by the two sovereign principles of pleasure and pain, and that it is the principle of utility that recognizes this subjection and employs it as the foundation of a system. The object of this system is to promote felicity, and to achieve that end with precision it is necessary to calculate which policies will produce a net balance of pleasure over pain. Armed with this scientific knowledge, the legislator will be able to pass laws that can be guaranteed to further the interests of the community. The view that this science should be useful is typical. Cesare Beccaria, in his argument for a reformed penal system (see Beccaria 1764), held that punishment should be determined with geometric precision, and that the probability of guilt amounts to moral certainty – something humans necessarily presuppose in daily life. The computation of such probability was undertaken by the Marquis de Condorcet, by far the most sophisticated eighteenth-century social scientist.

Condorcet stands at the end of a significant French tradition, which, although there is a Cartesian ingredient, has a similar genealogy to that of the British. This is evident in Etienne Bonnot de Condillac, the most systematic French writer. He too believed that moral reasoning was susceptible to the same exactitude as geometry, and also identified the association of ideas as the key to the study of human nature. Condillac sought to trace all ‘ideas’ to sensation thus rendering Locke’s ‘ideas of reflection’ derivative. In his Traité des sensations (Treatise of Sensations) of 1754 he traced the development of a statue, such that by the addition of each of the senses in turn it came to possess the full range of human mental ability.

Any account of human nature seemingly has to distinguish the nature of humans from that of animals. Georges, Comte de Buffon, who wrote the fullest scientific natural history (1749–89) in the eighteenth century, thought humans resembled animals materially but differed by virtue of possessing a soul, reason and language. It was a common task of the science of human nature to account for language ‘naturally’ by tracing its evolution from onomatopoeic interjections to grammatical abstractions, without recourse to divine interposition or rational direction. While Buffon retained a traditional account of human differentia, Julien Offroy de La Mettrie argued that if animals were machines then, contrary to Descartes, there was no need to withhold that designation from humans. More explicitly Newtonian, David Hartley attempted to provide a physiological foundation for the association of ideas.

Leaving aside Hartley’s own particular, ultimately religious, agenda, there is no reason to think Hume would find any incompatibility between that attempt and his own ambitions for a science of human nature; and it is those same ambitions that lie at the roots of contemporary social science.

Citing this article:
Berry, Christopher J.. Human nature, science of, in the 18th century, 1998, doi:10.4324/9780415249126-DB039-1. Routledge Encyclopedia of Philosophy, Taylor and Francis,
Copyright © 1998-2021 Routledge.

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