The Rise of Natural Philosophy, Scientific Revolution, and the Enlightenment (^) ‹ 109
square of the distance between them and directly proportional to the product of their
masses.” The Principia not only provided the correct calculations for planetary motion, it
set out “definitions” and “laws of motion,” which demonstrated how mathematical phi-
losophy was henceforth to be done.
For the rest of the seventeenth century, the methods of Newton and Descartes served as
competing models, with Newtonianism reigning in Great Britain and Cartesianism domi-
nating in continental Europe. But by the dawn of the eighteenth century, Newtonianism
had won out and served as a model not just for natural philosophy, but for an approach to
the understanding of human society—an approach that would come to be known as the
Enlightenment.
New Ideas About Natural Law, Human Nature, and Society
Isaac Newton had shown that, through the rigorous application of empirical observation and
reason, humans could discern the laws that God had created to govern the natural world.
His eighteenth-century successors, the philosophes, argued that the same process could lead to
knowledge of the natural laws that govern human behavior. Accordingly, the Enlightenment
view of society rested upon certain assumptions about the “natural state” of human beings.Thomas Hobbes
One assumption about human nature that was foundational to Enlightenment thought was
the belief that human beings could discern and would naturally follow their own self-interest.
Thomas Hobbes, the author of Leviathan (1651), asserted that self-interest motivated nearly
all human behavior. Specifically, Hobbes argued that human beings were naturally driven to
quarrel by competition, diffidence, and glory. Hobbes therefore concluded that “without a
common power to keep them in awe,” the natural state of man was one of war.John Locke
More typical of Enlightenment thought about human nature were the ideas of John Locke.
In his Essay Concerning Human Understanding (1689–1690), Locke argued that humans are
born tabula rasa (as “blank slates”). This contradicted the traditional Christian notion that
humans were born corrupt and sinful, and it implied that what humans become is purely a
result of what they experience. Accordingly, Locke argued that educational and social systems
that taught and rewarded rational behavior would produce law-abiding and peaceful citizens.
Locke shared Hobbes’s belief in self-interest, and its importance in Locke’s thought can
be seen in his influential theory of private property, which appeared in his Two Treatises on
Government (1690). Locke argued that God created the world and its abundance so that
humans might make it productive. To ensure that productivity, God established a natural
right to property. Private property is created, Locke argued, when an individual mixes a
common resource with his individual labor. For example, when an individual does the work
of cutting down a tree and crafting the wood into a chair, he has mixed a common resource
with his individual labor to create something that did not exist before. That creation is his
private property and, therefore, his incentive to be productive.Adam Smith
A typical eighteenth-century example of self-interest as natural law can be seen in the work
of Adam Smith, who applied Enlightenment ideals to the realm of economics. In The Wealth
of Nations (1776), Smith argued that there were laws of human labor, production, and trade
that stemmed from the unerring tendency of all humans to seek their own self-interest.15_Bartolini_Ch15_099-118.indd 109 27/04/18 1:54 PM