The natural law conception of ethics is more closely associated with Thomas Aquinas than with any other thinker, and Aquinas’ position is famously grounded in a metaphysics of Aristotelian essentialism and teleology. It is often claimed that this metaphysics was decisively undermined by the scientific revolution. Hence it might appear that modern science has refuted what has been, historically, the main approach to understanding natural law.

Alternative versions of natural law may seem to sidestep this difficulty by looking for foundations in something other than an essentialist and teleological conception of nature. For example, Locke’s theory of natural law is grounded in the thesis of divine ownership of human beings. Violating the rights to life, liberty and property that we have under natural law is, for Locke, essentially a matter of damaging God’s property.