Benjamin Martin: May I sit with you?
Charlotte Selton: It's a free country, or at least it will be.
Laws that govern the functioning of the universe can be thought of as Eternal Law. Scientific rules of physics, chemistry, biology, et al govern eternal law. These rules are self-evident--whether or not we understand or misunderstand their workings. The truthfulness of Eternal Law requires no explanation or proof in order for it to exist.
Human command cannot alter Eternal Law. As stated by Sir Thomas More's character in Robert Bolt's play A Man for All Seasons, "Some men think the Earth round, others think it flat...But if it is flat, will the King's command make it round? And if it is round, will the King's command flatten it?"
Natural Law governs human behavior in the context of Eternal Law. People have yearnings which they seek to fulfill. In the natural state of the world, people are in possession of reason and free will that can be employed in pursuit of desired ends.
Natural Law is flouted when one individual or group interferes with the pursuits of another individual. For example, confiscation of property is wrong in the context of Natural Law because it impairs human endeavors that produce things and/or trade for other things to enrich life.
When government interferes with the natural order of things, even if the beneficiaries of that intervention constitute the majority, someone will always pay the price of having his/her human nature transgressed upon.
Stated differently, government intervention is certain to violate the freedom of at least one individual.
The rules of social interaction necessary to allow individuals to pursue their inclinations are known as Natural Rights. Natural Rights are not granted by the government. As Jefferson famously observed, these rights are unalienable, and include the rights to life, liberty, and the pursuit of happiness. These rights are granted to us by our humanity, not by government.
Natural Rights are grounded in the principle of nonaggression. We are free to choose and pursue our interests, but only to the extent that our actions do not infringe upon the freedom of others.
Natural Rights can be expressed in various forms: speech, religion, assembly, association, self-defense, etc. However, all of these freedoms are extensions of one central right: the right to own property. Property begins with one's own body, and extends to our freedom to use it in pursuit of our interests and to enjoying the fruits of our pursuits.
As sagely noted by Rothbard (1982), an individual does not have a 'right to freedom of speech.' Instead, the person has the right to rent an assembly hall and speak to those who enter and listen, or to publish a pamphlet and distribute it to those willing to read it. What the individual has is property rights, including the right of free contract and the right to trade--be that trade in goods or ideas.
An important implication is that those who refuse to recognize some aspect of property rights are essentially denying the validity of all Natural Rights. It is inconsistent, for example, to claim a right to free speech while disparaging the right to tangible property.
Of course, such inconsistency is constantly on display among politicians and their special interest groups.
Rothbard, M.N. 1982. The ethics of liberty. Atlantic Highlands, NJ: Humanities Press.