philosophical argument for the natural law that human life is to be preserved – and
understandably so, since this is the argument to which Locke himself draws the most
attention. But it is not in fact his only argument. There is a separate line of argument,
running throughout both the First Treatise and the Second Treatise, that the natural law is
visible in the unfolding of history. By examining the course of human events, we can
discern God’s intention that human life is to be preserved. The historical line of argument
establishes a positive duty to actively preserve human life, as opposed to a merely
negative duty to avoid harming or destroying life. It also establishes premises that are
crucial to the overall political position of the Two Treatises, including his refutation of
Robert Filmer’s Adamic absolutism and his support for the right to revolution. These
premises are not established by the argument from equal capacities. Thus, Locke’s larger
case would fail if not for the historical line of argument – a good reason for Locke
scholars to start paying more attention to this aspect of Locke’s thought. This paper will
trace the presence of this line of argument and establish the argument’s importance in the
Two Treatises.
This type of argument is a conventional feature of natural-law philosophy, so it is not
surprising to find it in Locke. The scriptural touchstone for Christian natural-law theory is
Paul’s observation (Romans 2:14-15) that “the Gentiles, who have not the law, do by
nature the things contained in the law.” By “the law” Paul means the revealed law given
to the Jews; he is observing that human history shows that those who have not received
God’s law by revelation (the Gentiles) nonetheless know and obey it. Following Paul,
natural-law thinkers have always used the evidence of history as at least one of their main
arguments. Considering the question “whether there is in us a natural law,” Aquinas uses
Paul’s observation of Gentile history to set the keynote for his affirmative answer.
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Convention