Mill's Argument for Freedom of Expression Reconstructed

Revised October 30, 2003

The parenthesized numbers in the excerpt correspond to premises in the reconstructed argument below.

"A" designates an unstated assumption, used as premise.
"P" designates a premise, more or less explicitly stated.
"IC" designates an intermediate conclusion.
"FC" designates the final conclusion.

In his famous work On Liberty, John Stuart Mill writes, in defense of freedom of opinion and expression:

The received opinion may be false . . . or the received opinion being true, a conflict with the opposite error is essential to a clear apprehension and deep feeling of its truth. But there is a commoner case than either of these; when the conflicting doctrines, instead of one being true and the other false, share the truth between them; and the nonconforming opinion [the one not endorsed by the authorities] is needed to supply the remainder of the truth
. . . (19)

. . . we will now briefly recapitulate.

First, if any opinion is compelled to silence, that opinion may, for aught we can certainly know, be true (2). To deny this is to assume our own infallibility.

Secondly, though the silenced opinion be an error, it may, and very commonly does, contain a portion of the truth (5); and since the general or prevailing opinion on any subject is rarely or never the whole truth, it is only by the collision of adverse opinions that the remainder of the truth has any chance of being supplied.

Thirdly, even if the received opinion be not only true, but the whole truth, unless it is suffered [allowed] to be, and actually is, vigorously and earnestly contested [debated], it will, by most of those who received [accept] it, be held in the manner of a prejudice, with little comprehension or feeling of its rational grounds. (9) And not only this, but, fourthly, the meaning of the [true] doctrine will be in danger of being lost, or enfeebled, and deprived of its vital effect on the character and conduct (15): the dogma becoming a mere formal profession, inefficacious for good (17), but cumbering the ground, and preventing the growth of any real and heartfelt conviction, from reason or personal experience.

Sub-argument I--the benefits of truth itself

(1, A) It is beneficial to know the truth.
(2, P) The view suppressed by authority might be true.
(3, IC) If we suppress such views, we may lose access to the truth. (2)
(4, IC) Suppression of possibly true views risks loss of benefit. (1, 3)

Sub-argument II--the benefits of gleaning truth from partially false views

(5, P) The false view can contain a truth that, if added to the truths of the authorized view, can make it more complete and useful.
(6, IC) Access to partially false views can be beneficial. (5)
(7, IC) Suppression of such views can be harmful. (6)
(8, IC) Suppression of partially true views risks losing what is beneficial. (7)

Sub-argument III--the benefits of vigorous contestation for understanding complete and true views

(9, P) False views (a) make us pay closer attention to the reasoning behind the complete and true view and (b) force us to seriously evaluate the strength of the reasoning behind the true view.
(10, IC) False views can aid in the grasp and appreciation of complete and true views. (9)
(11, A) Whatever aids in understanding such views is beneficial.
(12, IC) False views can be (indirectly) beneficial even when the complete and true view is available. (10, 11)
(13, IC) Suppressing false views, even when the complete and true view is available, risks loss of benefit. (12)

Sub-argument IV--the benefits of vigorous contestation for integrating the complete and true view into our lives.

(14, A) Allowing false views provide an opportunity to have a debate between the complete, true view and the false view.
(15, P) Engaging in controversies with false views can make the complete and true view a living presence instead of a dead dogma.
(16, A) It is beneficial for a true view to be a living presence instead of a dead dogma.
(17, IC) Suppression of false views, even when the complete and true view is available, risks loss of benefit. (14-16)

(18, A) We ought not to risk loss of benefit. (Based on Mill's Social Consequentialism)
(19, P) All views are either possibly true, partly true, or false.
(20, FC) We should not suppress any views. (4, 8, 13, 17-19)