Cicero, natural law, and why you can’t marry a plant


Have you ever wondered why certain things seem to make sense while others just don’t seem right? Why, for instance, do humans get great pleasure out of relationships with each other yet struggle to find any common bond with, say, pencil shavings?

Why do humans from all parts of the globe have a startlingly similar concept of right and wrong behavior, of fair vs. unfair? Marcus Tullius Cicero (106-43 B.C.), one of the Founding Fathers’ richest sources for insight into the power of natural law, answers this question (all quotes taken from William and Allan O. Ebenstein’s Great Political Thinkers):

True law is right reason in agreement with nature; it is of universal application, unchanging and everlasting; it summons to duty by its commands, and averts from wrong-doing by its prohibitions. … It is a sin to try to alter this law, nor is it allowable to attempt to repeal any part of it, and it is impossible to abolish it entirely. We cannot be freed from its obligations by senate or people, and we need not look outside ourselves for an expounder or interpreter of it. And there will not be different laws at Rome and at Athens, or different laws now and in the future, but one eternal and unchangeable law will be valid for all nations and all times, and there will be one master and ruler, that is, God, over us all, for he is the author of this law, its promulgator, and its enforcing judge. Whoever is disobedient is fleeing from himself and denying his human nature, and by reason of this very fact he will suffer the worst penalties, even if he escapes what is commonly considered punishment.

The reason that the human race has such a shared sense of right and wrong is because we all come from the same source: God. Cicero goes on to say that men, through force of law or other means, cannot alter justice. Only those man-made laws which are in accordance with the universal laws of nature can accurately “inflict punishment upon the wicked and protect the good.”

The most foolish notion of all is the belief that everything is just which is found in the customs or laws of nations. … What of the many deadly, the many pestilential statues which nations put in force? These no more deserve to be called laws than the rules a band of robbers might pass in their assembly. For if ignorant and unskillful men have prescribed deadly poisons instead of healing drugs, these cannot possibly be called physicians’ prescriptions; neither in a nation can a statute of any sort be called a law, even though the nation, in spite of being a ruinous regulation has accepted it.

Therefore Law is the distinction between things just and unjust, made in agreement with that primal and most ancient of all things, Nature; and in conformity to Nature’s standard are framed those human laws which inflict punishment upon the wicked and protect the good.

This is why correct principles are so critical. Correct principles are those which agree with the laws of nature, or natural law. When families, cities, states and nations develop statutes grounded in natural law, then human beings in all of those units can live peacefully and happily together in community. For the undesirable alternative, Cicero provides the illumination:

But if the principles of Justice were founded on the decrees of peoples, the edicts of princes, or the decision of judges, then Justice would sanction robbery and adultery and forgery of wills, in case these acts were approved by the votes or decrees of the populace. But if so great a power belongs to the decision and decrees of fools that the laws of Nature can be changed by their votes, then why do they not ordain that what is bad and baneful shall be considered good and salutary? Or, if a law can make Justice injustice can it not also make good out of bad?

Fortunately for us, natural law is the basis for much of the U.S. Constitution and our American culture. In his book The Five Thousand Year Leap, Cleon Skousen enumerates a few examples of concepts based on natural law:

  • unalienable rights (Thomas Jefferson framed them as “Life,Libertyand the Pursuit of Happiness” in the Declaration of Independence)
  • unalienable duties (don’t kill, don’t steal, be honest, honor the law, etc.)
  • habeas corpus
  • limited government
  • separation of powers
  • checks and balances
  • right of self-preservation
  • right to contract
  • laws protecting the family and marriage
  • justice by reparation
  • right to bear arms
  • no taxation without representation

So, the next time you’re wondering why you can’t legally marry a fern, just remember: You’re a human being. But why is it that human beings have such a mutual sense of right and wrong? Aren’t there certain variations of human beings that share a symbiotic relationship with ferns? Actually, no. That’s because we all come from the same source of reason and rightness: God.

Rational human beings recognize that it would be both unreasonable and not “right” to marry a fern, just as any reasonable and right-minded human being would think it “wrong” for a fellow human to randomly slap strangers upside the head. God’s law, natural law, is instilled into the very core of each of us and provides the common foundations of justice and fairness innate to each of us. At bottom, operating against natural law can never result in true happiness – the universal aspiration of all mankind.