Stony Brook University

would entail much greater difficulty:
What duty is, cannot be understood without a law; nor a law be known or
supposed without a lawmaker, or without reward and punishment; so that
it is impossible that this, or any other, practical principle should be innate,
i.e., be imprinted on the mind as a duty, without supposing the ideas of
God, of law, of obligation, of punishment, of a life after this, innate. (E
1.2.12)
Locke’s argument here is two-fold: (1a) For an innate practical principle to be assented
to, it must be a proposition; (1b) Assent to this proposition would require assent to many
other propositions and ideas which are also very far from being innate. (2) The ground of
obligation is divine command, supported by divine sanction. Terms such as ‘duty’ are
understandable only under the supposition that a supreme lawgiver establishes and
enforces the moral law. This reflects Locke’s well-known voluntarism, according to
which moral principles are not ultimately determined by the demands of reason, but by
the command and will of God. 14 Locke’s whole argument here, then, suggests that moral
principles are ultimately not to be assented to, but rather are to be obeyed. 15 But then,
God’s commands are not innate to us, any more so than the idea of God is innate; and
Locke denies that the idea of God is innate, since it may be attained by reflecting on the
works of creation (E 1.3.9). Nor are any other ideas, such as self, being, and immortality
innate. Therefore, moral principles are not innate, and their true grounding principle is
God’s command.
Despite all of his rejections of innate of ideas and practical principles, and aside
from the voluntarist grounds, Locke nevertheless thinks that there are universal moral
truths and, moreover, that they are “capable of demonstration” (E 1.2.1). In several places
throughout the Essay Locke emphasizes the demonstrability of practical principles, but
most strikingly in Book Four.
The idea of a supreme Being, infinite in power, goodness, and wisdom,
whose workmanship we are, and on whom we depend; and the idea of
ourselves, as understanding, rational creatures, being such as are clear in
us, would, I suppose, if duly considered and pursued, afford such
foundation of our duty and rules of action as might place morality amongst
the sciences capable of demonstration: wherein I doubt not but from selfevident
propositions, by necessary consequences, as incontestible as those
14 Locke’s voluntarism, is better expressed in this quote: “But yet I think it must be allowed that several
moral rules may receive from mankind a very general approbation, without either knowing or admitting the
true ground of morality; which can only be the will and law of a God, who sees men in the dark, has in his
hand rewards and punishments, and power enough to call to account the proudest offender” (E 1.2.6). Of
course, God is also reasonable, but his will and enforcement are the grounds of morality. For a detailed
analysis of Locke’s voluntarism, see Jerome Schneewind, The Invention of Autonomy, and his article in The
Cambridge Companion to Locke. According to Schneewind, “Locke makes it clear that he does not view
God as a tyrant” (SA 154). However, as Schneewind points out, citing Thomas Burnet, if morality depends
on a law governed by God’s sanction, which it does for Locke, then it is not possible for God to have moral
attributes (SL 206). This would appear to be a serious problem for Locke.
15 Thus, the demonstrability of moral principles is ultimately beside the point for Locke.
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