From the fundamental notions of a state, we have discovered how a man may exercise free judgment without detriment to the supreme power: from the same premises we can no less easily determine what opinions would be seditious. Evidently those which by their very nature nullify the compact by which the right of free action was ceded. For instance, a man who holds that the supreme power has no rights over him, or that promises ought not to be kept, or that every one should live as he pleases, or other doctrines of this nature in direct opposition to the above-mentioned contract, is seditious, not so much from his actual opinions and judgment, as from the deeds which they involve; for he who maintains such theories abrogates the contract which tacitly, or openly, he made with his rulers. Other opinions which do not involve acts violating the contract, such as revenge, anger, and the like, are not seditious, unless it be in some corrupt state, where superstitious and ambitious persons, unable to endure men of learning, are so popular with the multitude that their word is more valued than the law.
However, I do not deny that there are some doctrines which, while they are apparently only concerned with abstract truths and falsehoods, are yet propounded and published with unworthy motives.... Reason should nevertheless remain unshackled. If we hold to the principle that a man's loyalty to the state should be judged, like his loyalty to God, from his actions only—namely, from his charity towards his neighbors; we cannot doubt that the best government will allow freedom of philosophical speculation no less than of religious belief. I confess that from such freedom inconveniences may sometimes arise, but what question was ever settled so wisely than no abuses could possibly spring therefrom? He who seeks to regulate everything by law is more likely to arouse vices than to reform them. It is best to grant what cannot be abolished, even though it be in itself harmful. How many evils spring from luxury, envy, avarice, drunkenness and the like, yet these are tolerated—vices as they are—because they cannot be prevented by legal enactments. How much more, then, should free thought be granted, seeing that it is in itself a virtue and that it cannot be crushed! Besides, the evil results can easily be checked, as I will show, by the secular authorities, not to mention that such freedom is absolutely necessary for progress in science and the liberal arts: for no man follows such pursuits to advantage unless his judgment be entirely free and unhampered.
But let it be granted that freedom may be crushed, and men be so bound down that they do not dare to utter a whisper, save at the bidding of their rulers; nevertheless this can never be carried to the pitch of making them think according to authority, so that the necessary consequences would be that men would daily be thinking one thing and saying another, to the corruption of good faith, that mainstay of government, and to the fostering of hateful flattery and perfidy, whence spring stratagems, and the corruption of every good art.
It is far from possible to impose uniformity of speech, for the more rulers strive to curtail freedom of speech the more obstinately are they resisted; not indeed by the avaricious, the flatterers, and other numskulls, who think supreme salvation consists in filling their stomachs and gloating over their money-bags, but by those whom good education, sound morality, and virtue have rendered more free. Men, as generally constituted, are most prone to resent the branding as criminal of opinions which they believe to be true, and the proscription as wicked of that which inspires them with piety towards God and man; hence they are ready to forswear the laws and conspire against the authorities, thinking it not shameful but honorable to stir up seditions and perpetuate any sort of crime with this end in view. Such being the constitution of human nature, we see that laws directed against opinions affect the generous minded rather than the wicked, and are adapted less for coercing criminals than for irritating the upright; so that they cannot be maintained without great peril to the state.
Moreover, such laws are almost always useless, for those who hold that the opinions proscribed are sound, cannot possibly obey the law; whereas those who already reject them as false, accept the law as a kind of privilege, and make such boast of it, that authority is powerless to repeal it, even if such a course be subsequently desired.
... And, lastly, how many schisms have arisen in the Church from the attempt of the authorities to decide by law the intricacies of theological controversy! If men were not allured by the hope of getting the law and the authorities on their side, of triumphing over their adversaries in the sight of an applauding multitude, and of acquiring honorable distinctions, they would not strive so maliciously, nor would such fury sway their minds. This is taught not only by reason but by daily examples, for laws of this kind prescribing what every man shall believe and forbidding any one to speak or write to the contrary, have often been passed as sops or concessions to the anger of those who cannot tolerate men of enlightenment, and who, by such harsh and crooked enactments, can easily turn the devotion of the masses into fury and direct it against whom they will.
How much better would it be to restrain popular anger and fury, instead of passing useless laws, which can only be broken by those who love virtue and the liberal arts, thus paring down the state till it is too small to harbor men of talent. What greater misfortune for a state can be conceived than that honorable men should be sent like criminals into exile, because they hold diverse opinions which they cannot disguise? What, I say, can be more hurtful than that men who have committed no crime or wickedness should, simply because they are enlightened, be treated as enemies and put to death, and that the scaffold, the terror of evil-doers, should become the arena where the highest examples of tolerance and virtue are displayed to the people with all the marks of ignominy that authority can devise?
He that knows himself to be upright does not fear the death of a criminal, and shrinks from no punishment. His mind is not wrung with remorse for any disgraceful deed. He holds that death in a good cause is no punishment, but an honor, and that death for freedom is glory.
What purpose, then, is served by the death of such men, what example is proclaimed? The cause for which they die is unknown to the idle and the foolish, hateful to the turbulent, loved by the upright. The only lesson we can draw from such scenes is to flatter the persecutor, or else to imitate the victim.
If formal assent is not to be esteemed above conviction, and if governments are to retain a firm hold of authority and not be compelled to yield to agitators, it is imperative that freedom of judgment should be granted, so that men may live together in harmony, however diverse, or even openly contradictory their opinions may be. We cannot doubt that such is the best system of government and open to the fewest objections, since it is the one most in harmony with human nature. In a democracy (the most natural form of government) every one submits to the control of authority over his actions, but not over his judgment and reason; that is, seeing that all cannot think alike, the voice of the majority has the force of law, subject to repeal if circumstances bring about a change of opinion. In proportion as the power of free judgment is withheld we depart from the natural condition of mankind, and consequently the government becomes more tyrannical.