There is perhaps no political question so important to the interests of society, as that of the operation of unrestrained discussion on all subjects whatever. Governors have, at all times, and in all places, been prone to discountenance it on political questions, and the clergy have induced the same proneness on religious topics. But the situation either of political rulers, or the adherents of clerical hierarchy, by no means secures their judgment from bias, and implicit confidence is hardly due to opinion from this quarter. If, upon investigation, it should appear, that almost every valuable improvement in human society, has originated in discussion, partial and limited as it has hitherto been, and that it is the only permanent source, whence all future improvements in knowledge, virtue or happiness, can be reasonably expected, we shall do well, sedulously to watch over and preserve it, as the most important and inestimable of our rights.

The great object of society -- that object for which alone government itself has been instituted, is the general good. But to obtain this, we should understand in what it consists; and discover, so far as we can, what are the best means of securing it. This cannot be known by intuition, but must be the fruit of knowledge founded on experience. All reasoning is deduced from facts: we all agree with the poet -- "How can we reason but from what we know?"

For judgment, expectation, prediction -- every conclusion whatever, can be formed only from what has been previously observed and known. Whence has the present age derived its superior wisdom, and superior accommodations to remoter periods, but by improving on the practice, and reasoning from the experience, of former times? Natural intellect is not more vigorous or more acute now, than it was in the infancy of society. It has been the multiplication of facts alone, those sole materials of knowledge, that has conferred this pre-eminence.

Most of the evils, indeed all the political evils of life, may be ascribed to ignorance. This prolific source of mischief and misery, has made the mass of mankind, in all countries, insensible to their own welfare, and subservient to the caprice, resentment or ambition of the few; and rendered the page of history little more than the chronicle of war, oppression and calamity. Even virtue, or the active desire to do good, unless directed by knowledge, may produce much evil. Of this, the long and horrid catalogue of religious persecutions affords abundant proof.

It appears, therefore, that knowledge is the most important instrument of human welfare. But it can exist in an eminent degree, and on a stable foundation, only by discussion; and its increase and extension will be proportioned to the freedom of discussion.

Knowledge is valuable as it furnishes the means of just conclusions: but as the conclusions from moral and political (I may add religious) propositions, are not self-evident, the more they are discussed and examined, and the more various the points of view in which they are considered, the greater is the probability that truth will be the result: there is no exploded error, however absurd and pregnant with mischief, that has not been regarded in its day as a valuable truth, and tenaciously defended.

It may perhaps be urged, and plausibly urged, that the welfare of the community may sometimes, and in some cases, require certain restrictions on this unlimited right of enquiry: that publications exciting to insurrection or immorality for instance, ought to be checked or suppressed. Not to dwell upon the difficulty of ascertaining the proper boundary of such restrictions, it may be observed, that opinions palpably false and of bad tendency, will never be generally received, and their promulgation must eventually do good. The mass of talents, of knowledge, and of respectability will, in every country, from interest as well as principle, be on the side of good order and morality. There can be few who, from ignorance or design, will be tempted publicly to support opinions inimical to the general welfare; and in cases where it may occur, the investigation that will ensue, and the confutation of such doctrines however plausible (which in the end must take place if they really are unfounded and of mischievous tendency) will establish truth more decisively, than could be effected in any other way. If they appear insidious and less obviously false, we shall do well to remember, that false opinions cannot be suppressed but at the risk of suppressing those that are valuable; for it is only after discussion that their nature and tendency can be known and appreciated. The doctrines of Aristotle have been regarded as inviolable, and the opinions which Galileo was compelled to recant, are now considered as established truths.

It may well admit of question, whether it be safe to entrust any government with a power of this kind. It is one that the public cannot often require to be exercised, but which there may be frequent temptations to abuse; and if the right of government to proscribe the avowal of one opinion be admitted, absolute power is in its hands; for the principle once conceded, may be extended to every other which insidious despotism may think fit to hold out as dangerous.

The only test by which opinion can be tried, is human reason founded upon human experience, and this can perhaps be exercised with a better prospect of just conclusions, by the people than by their rulers. The immediate interest of the people is to discover and promote the general good: that of governors to extend their own power, or preserve it by the continuance of the present order of things. Should false opinions be propagated, is it probable that the majority of the people (especially if they be accustomed to free enquiry) will be misled by them, and that persons in power only will have the acuteness and discernment to detect their fallacy? But were even this the case, surely the friends of the existing establishment, with truth on their side, and the collateral aids of wealth and power, will have no difficulty in confuting them. It is too often the interest of men in power to discourage discussion, and that in proportion as their conduct is faulty; and it may be taken for granted, that the disposition to discourage it, is always a just ground of suspicion. But the people have nothing to dread from investigation: they can derive only advantage from it. Political institutions, moreover, having the most extensive influence on human welfare, and being in their own nature difficult to change or modify, it seems that latitude of discussion is more necessary on this than on any other subject, error having in this case a greater chance of being perpetuated....

The restraints imposed on freedom of speech and writing, are evidently calculated to produce the mischief they ostensibly aim to destroy. While one party assumes a right to suppress the opinions of those who differ from them, and the other experiences a degrading and unjustifiable subjection -- violence, ill-will, and rancour must subsist. Governments tenacious of an unaltered existence, would perhaps do well to consider that these restrictions serve only to excite more ardent opposition, and that the irritation of restraint carries men beyond what in other circumstances, they would have thought of. Men are proverbially careless of advantages always in their power; but to raise any object in their estimation, render it difficult of attainment, and they will desire it with increased ardour, and pursue it with ten-fold activity. Mere liberty of investigation will not induce this rancourous opposition; the ebullitions of party warmth will evaporate of themselves if left to themselves: but when once the spirit of enquiry has gone abroad, prohibitions, penalties, and all that fear may dictate to preserve power, are so many manifestations of impotence, and operate only to animate research. If, indeed, it were possible entirely to suppress communication of sentiment, the desired end might be accomplished: men would then cease to think, and the human mind would soon degenerate to a level with the brutes....

Free investigation gave birth to American independence; and is peculiarly congenial with the spirit of a constitution, that on the wise and animating idea of the perfectability of human nature, has made a periodical provision for peaceful and gradual improvement in its political institutions: and the longer impartial discussion shall precede the period of revision and reform, the more secure shall we be of the adoption of wise and well digested plans....

[For more of Mrs. Priestley's portion of the essay, and for Mr. Cooper's, please see this PDF; I will also blog more of the Cooper portion tomorrow. -EV]