We established in the previous chapter that liberty rests on observable facts about human nature: the body, the occupation of space, the appropriation of things, the individuality of perceptions. But the human being is not only a body, he is also, and perhaps above all, a mind. From this single fact flow religious tolerance, freedom of expression, freedom of the press, and free education.

Charles Comte (1782–1837), in his Cours de droit naturel, a series of lectures delivered in Lausanne around 1830, of which we still possess the manuscript, makes this point from the very first lesson: a human being devoid of cognitive capacity would scarcely be recognized as human. We form bonds with others precisely because they are thinking beings, because they have feelings, ideas, convictions that we can share and debate.

This capacity for thought is accompanied by something that no materialist account can ignore: the pleasure of thinking. Consider the case of Father Yves-Marie André, a Jesuit scholar whose superiors forbade him from continuing his research on Malebranche. He suffered profoundly, though not everyone would feel the same deprivation with equal intensity. For many people, developing their ideas, exchanging them, teaching them to others, constitutes one of the deepest sources of human satisfaction. The pleasure of learning, the pleasure of teaching, the pleasure of intellectual discovery, these are facts of human experience, not luxuries reserved for the privileged few.

Thought is a manifestation of the will. We feel, we conceive projects and ideas, and we naturally wish to transmit them. Expression, whether spoken, written, or printed, is simply the materialization of thought. If we are free to will, and free to think (since no power on earth can prevent us from thinking), then there is a strong natural presumption in favor of free expression. To break the chain between sensation, will, thought, and its material expression requires very powerful arguments indeed.

Here we encounter a fundamental insight: the inviolability of conscience. One can burn a man for his opinions, it has been done, but one cannot burn his thought. The stake destroys the thinker, not the thinking. No authority has ever had power over thought itself; it can only reach its material expression. We are free to change our ideas, to pursue them to their conclusion, to abandon one intuition and embrace another. This freedom is not a gift of legislation. It is a fact of our nature.

Benjamin Constant (1767–1830), the great Swiss-French liberal, devoted much of his career to defending freedom of the press and individual liberties amid the turbulent political upheavals of post-revolutionary France. In his Principes de politique (1815), he expressed the implications of this intellectual self-ownership with characteristic force:

In other words, since the individual is the sole owner of his thought, to suppress it in the name of any supposedly higher reason, whether religious or rationalist, is fundamentally unjust. The property of thought belongs to the thinker, and no external tribunal, however well-intentioned, is competent to rule on the contents of another man's mind.

Why, beyond the mere recognition of a natural right, should we actively value freedom of expression? The answer lies in a great idea that the 18th-century philosophical movement brought to maturity: human perfectibility.

Nicolas de Condorcet (1743–1794), who stood at the crossroads of the Enlightenment philosophers and the Physiocrat economists, a close friend of Turgot, wrote his masterwork, the Esquisse d'un tableau historique des progrès de l'esprit humain, under extraordinary circumstances. In hiding, about to be arrested and executed during the Terror, without books, he composed in a single room a sweeping vision of human progress across the ages.

The core thesis was revolutionary: contrary to the Christian doctrine of the Fall, which posits a descent from original perfection, human civilization is ascending. Each generation transmits its discoveries to the next, and humanity advances from century to century. But this progress is not automatic. New ideas, audacious, pioneering, often initially rejected, must be freely communicated. The discoverer must be able to teach his conceptions to others, to his descendants, and to society at large, so that what was once considered too bold may be tested, accepted, and put into practice.

The debate of ideas functions much like economic competition: among many competing merchants, it is the one who produces best and at lowest cost who succeeds. Similarly, in the marketplace of ideas, confrontation allows the best-founded conceptions to prevail, because everyone can observe their effects and judge whether they accord with the facts. The natural variety of human beings, which we have already noted, is itself the source of this variety of ideas. Individuals born with different constitutions, raised in different environments, will inevitably develop different perceptions, different sensibilities, different judgments. Free debate is therefore not an optional luxury; it is the indispensable mechanism by which the most well-grounded ideas can reach their audience and advance civilization.

Freedom of the press extends the principle of free expression into the political realm. Human actions, and especially collective, governmental actions, produce effects that are felt differently by different people. A regulation affecting a particular industry causes suffering to those within it that others may not perceive at all. Each individual must be able to express and publicize the consequences he observes: "This institution harms me, and here is how."

The Abbé de Saint-Pierre, at the beginning of the 18th century, compared political institutions to clocks that need to be wound from time to time. Indeed, laws and institutions grow stale; they require periodic reform. But reform requires informed public opinion, and informed public opinion requires a free press.

French history provides a stark illustration of what happens without this mechanism. In the 18th century, the Enlightenment philosophers electrified the intellectual elite with their ideas. Turgot, as minister, attempted sweeping reforms. But there were no newspapers accessible to the common people, no channels through which an informed public opinion could form and sustain the reform effort. The mass of the population was excluded from the great intellectual debate. The result was that change could only come through revolution, through the violent overthrow of the entire system, rather than through gradual, prepared, peaceful reform.

The free press, by contrast, acts as what the liberals called "the tribunal of public opinion", a mechanism that is both free and rapid. Citizens observe the effects of laws and institutions, formulate their judgments, and communicate them publicly. This tribunal costs nothing; it operates continuously; and it prepares the ground for reform so that violent upheaval becomes unnecessary. It is, in a sense, a profitable enterprise: private newspapers and journals sustain themselves economically while simultaneously performing the essential civic function of democratic criticism.

We arrive at free education, the freedom that, logically, should require no separate defense, yet which encounters the greatest resistance.

Consider: if we accept freedom of expression, does it not follow that we accept the freedom to teach? If we accept freedom of the press, the right to communicate one's ideas through print, how can we deny the right to communicate those same ideas in a classroom? And if we accept religious freedom, the freedom not merely to pray silently at home (which exists under every tyranny) but to worship publicly, to found churches, to propagate one's faith, then we must accept the freedom to educate one's children according to one's beliefs.

Édouard Laboulaye (1811–1883), one of the great defenders of educational freedom during the era of Jules Ferry's reforms, fought this battle with passion, and, unfortunately, lost it. The liberals lost again more decisively in the following decades. Yet the arguments remain unanswerable.

The case against state monopoly in education rests on two facts. First, the natural fact of parental love. Mothers and fathers are the natural tutors of their children. The state, a succession of political parties, elected in moments of enthusiasm, on vast programs whose details most voters do not know, is an artificial substitute for this natural guardianship. Of course, there may be cases of abuse where recourse to an alternative guardian is needed. But to fabricate in advance, and for all children, a substitute tutor, to replace the parent by default, is neither logical nor grounded in the facts of human existence.

Second, the fact of human diversity, which we have encountered again and again. Children are not identical. From birth, they differ in physical capacities, temperaments, aptitudes, and inclinations. To teach the same things in the same way to children who have been made differently by nature is to postulate something that does not exist, the uniformity of human beings. Only educational freedom, with its competition of schools, methods, rhythms, and programs, can accommodate this irreducible diversity and allow each individual to develop according to his own nature.

In the lessons that follow, we will move from these civil liberties to the factual foundations of economic freedom, the freedom of work, of trade, and of property in its material forms.