Many Christians deny the validity of biblical law for modern society and believe that good civil government may be realized by acting in concert with unregenerate moralists under the banner of “natural law.” This may produce temporary progress, but it supposes that there is an independent universal ethic accessible to all humanity. However, this point of view fails to take into account the clear teaching of the Bible concerning the state of unregenerate man (Romans 3:10-18). It also assumes that fixed truth exists independent of God. In other words, when a Christian embraces natural law theory he is suggesting that unregenerate man is willing and able to seek after a fixed truth that is independent of the Creator and yet sanctioned by Him.
Plato’s natural law theory proposed the existence of absolute knowledge or “Idea” along with two other eternal and independent principles: the Demiurge and matter. Although the Demiurge is independent of absolute knowledge it is not equally supreme. Instead, the Demiurge is second in the trivium with matter taking the third-place. Thus, for Plato, there is an overarching Idea which is the source of a universal ethic, independent of the Demiurge or the gods and thus wholly free of religion. However, Plato realized that man’s knowledge of the Idea is based upon observation of a world in flux. Therefore human reason may approximate the truth at best but never really know the truth in any fullness.
Thomas Aquinas adopted Platonic philosophy (via Plato’s pupil Aristotle), and attempted to overcome the problems presented by Plato in claiming that man might arrive at a true knowledge of God – rather than Plato’s Idea – through unaided human reason (i.e. in the absence of faith). Aquinas argued that this capability was original with Adam and is retained in fallen Man. But again we find that an attempt to establish a workable natural law theory falls short when viewed in the light of Scripture (Romans 1:18-23).
Although it is true that unregenerate men retain a sense of Deity it is likewise true that natural man is at war with God (Romans 8:6-8), and does everything within his power to hold down the knowledge of God. Moreover, it is true that nature speaks to the existence of God but it is likewise true that nature is neither normative nor independent of God and along with humanity groans under the deforming burden of sin (Genesis 1;1, 3:17, Romans 8:19-22). Therefore human reason basking in the light of nature is unable to arrive at fixed truth or agree upon a universal civil ethic.
For instance, Jean-Paul Sartre suggested that law is a product of the individual thus eliminating the possibility of a panoptic moral code. John Dewey taught that morality may only be discovered through trial and error. Although Dewey claimed that his philosophy was grounded in collective reason his approach to a universal ethic was decidedly individualistic as “experience and nature” vary from one person to another.
It should be clear that there is no such thing as a universal system of natural law that is accessible to fallen human reason. Acceptance of natural law philosophy paralyzes Christian efforts to transform society because it denies specific biblical blueprints for social reform. Ironically, Christians often deny the existence of biblical blueprints for the same reason that unregenerate men do. In other words, there remains a measure of rebellion in the hearts of those who claim to follow the King of the universe. They prefer to bow the knee to Man rather than submit to the One who gave His life for them.