Given the volume of books about freedom of speech under our First Amendment, it is curious that almost no-one has spent much time trying to define the term. The possible explanation may be that most such books are written by law professors, who are trained to assume that legal terms are moderately well-defined and then to look around the edges for lacunae that need to be filled in. Exponents of the law rarely start from the premise that "the law is a ass", so, despite the use of the so-called "Socratic method" to teach law, professors tend not to rip structures down to first principles.
Upon close examination, free speech appears to be a redundant phrase like "free gift". If speech itself was the second or third technology discovered by humans (assuming that weapons and fire came first), we may regard the "freedom" that ensued as being a case of technological determinism; speech naturally brought with it ranting and cursing, as well as exultation, gloating and other manifestations of emotional human nature. All speech was free until someone objected to it; when that objection was enforced by violence on the part of someone in authority, the first "free speech" dispute occurred.
We arrive immediately at an ambiguity in the phrase: "free speech" may refer to the speech itself, or to a set of conventions--a human rulebook-- that guarantees its freedom. While the latter approach incorporates the idea of democracy by reference, the former, of course, does not presuppose any particular system of government. We can find examples of "free speech" in the most totalitarian surroundings--even Hitler was not exclusively surrounded by yes men; the more secure a dictator is in his authority, the more likely he is to tolerate some dissent among his trusted advisers. Job spoke freely to God, who had the awesome and fearful power to kill him with a single word of wrath.
Continuing to concentrate on the first sense of the phrase--the quality of the speech itself, not the system in which it is uttered-- we find that most examples of free speech discussed by commentators attract interest only because the state reacted negatively to them. This is not much of a basis for an analysis of what makes speech "free" and what types of speech we might regard as "unfree." Given that humans, since the day they began expressing themselves, have never stopped complaining, examples of "unfree" speech are actually rather hard to come by. The most significant example which comes to my mind are some disappointing, sycophantic essays of Seneca addressed to the emperor, which lean so far in the direction of vile flattery that they heavily disguise the message the author wished to deliver.
This suggests a definition of "unfree" speech as insincere expression delivered in careful accordance with the perceived expectations of authority. But, once again, you can look in the most despicable times of human totalitarian violence without finding much speech that meets this definition; or at least not as much as you would expect. For example, Goering's infamous talk to the SS about the Final Solution, in which he attacks them for mercy to the Jews and says that we must remain good fellows, while being hard enough to see 1,000 corpses in a pile without flinching. This horrible discussion bears all the traces of the speech of a free man: one senses that Goering was unguarded and easy in his choice of phrase, and that he sincerely believed that he was a "good fellow" and that the mass murder of Jews was an unpleasant but necessary task. Certainly, if one goes down a level, to the German press of that time, there are more examples of "unfree speech"--simplistic propaganda and vile flattery--than in the private or secret conversations of the rulers.
Perhaps it is demanding too much to assume that "unfree speech" necessarily is insincere. Goering's discourse, though sincere, was completely in accordance with state policy, and he ran no risk of being punished for it. The problem with deleting insincerity as a condition of "unfree speech" is that we no longer have anything internal to the speech itself as a part of the definition. Two people make honest, forceful statements. One is rewarded because he supports state policy, the other is punished because he opposes it. In this case, we probably should not be trying to define "free speech" at all, but should fall back to our second interpretation of the phrase: a focus on the rulebooks which permit or limit freedom of expression.
It is important not to make the common error of assuming that speech is "unfree" because disfavored. Speech calling for the overthrow of a democratic government and the immediate institution of the harshest form of communism is the purest example of free speech in a democracy--where it is considered radical, disfavored expression.
An obvious criticism of what I have just said is that the opposite of "free speech" is not "unfree speech" but rather silence. There is certainly truth to this; but then we might as well talk about "speech" versus "silence", and the addition of the adjective "free" doesn't necessarily add anything. The phrase "free speech" assumes that there is a category of speech which is not "free". Also, we can at least evaluate examples of speech, but it is much harder to determine the motives for silence, nor can we measure relative speech versus relative silence under different forms of government.
If we hold to the condition of sincerity as part of a definition of "free speech", we face the problem that there is no objective way to determine a speaker's sincerity. Free speech therefore cannot be a binary condition, but like anything else in the fuzzy world of human thought, must fall on a spectrum, from the total dishonesty of the con man to the rigid and dangerous sincerity of the activist who has nothing to gain but his "soul." In between lie shades of manipulation and self interest: yes, I sincerely want you to take an action which will bring me personal gain. My advocacy of this action is perfectly honest, but I have not disclosed my motives.
Here's a thought experiment: let's establish an imaginary "free speech tribunal" which has the task of distinguishing speech which is "free" from that which is not. Since tribunals act in furtherance of some governmental policy goal, let's imagine that the reason for this one is to promote "free speech" in the democratic republic of Walden. Therefore, there is some reward which will be given to "free" expression and some penalty, however mild, for speech our tribunal determines to be "unfree."
At the first public meeting of the tribunal, up pops a citizen, Tom Paine, who says, "I object to the existence of the Free Speech Tribunal (FST). First, there is no objective definition of 'free speech' which we can all accept, so I don't want you spending my tax money pursuing a chimera. While you are using a definition that involves the 'sincerity' of the speech, my preferred definition might involve the 'risk' or 'forcefulness', while my neighbor might believe that 'only that speech is free which promotes man's subjection to God.' Secondly, you are using a definition that assumes a spectrum of 'freeness' rather than a binary setting of 'free' or 'unfree'. I understand that you plan to give higher financial incentives for 'more free' versus 'less free' speech, but these determinations are inevitably going to be so arbitrary that we in the audience will greatly disagree with them.
"The criteria you must use to reach your determination, even if sufficiently well defined, are nonetheless based on things that cannot be measured. How can anyone really determine the 'sincerity' of a speaker? Yes, we all rely on verbal cues and our own common sense. This is fine for daily decisions which we make about whether to trust people, but it seems like a very poor way to decide whether to grant a financial reward or to censure someone. I simply don't want the state making decisions of any kind based on such a fuzzy, subjective methodology.
"The final and most significant problem that I have is that the FST will accomplish the exact opposite of what it set out to do. Your announced goal is to encourage the proliferation of 'free speech' on Walden--something impossible to do anyway, since we cannot agree what that is. Since we, the honorable members of the FST included, are all flawed human beings, the possibility exists that you have come up with an incorrect or insufficient definition of free speech. Regardless of the truth or falsity of your definition, it is human nature that people, in order to obtain the reward and avoid your censure, will conform their speech to your definition. It seems to me that 'speech uttered in conformity with government preference' may meet your definition: it will be sincere, as in 'I sincerely want to receive the reward'. But it won't be any kind of free speech I, or most of the people in this audience, recognize. "If you want to promote free speech, the best thing the FST could do would be to dissolve itself; the best thing the republic of Walden could do would be: stay out of it! Don't intervene."
"Free speech" in fact is a phrase like "free gift". There is only speech, and government opposition to it. Speech lies on a spectrum, and government is only good at binary determinations--the law is so often a sledgehammer where a scalpel is required. The more useful lens is our second category: lets not speak of "free speech" but of "freedom of speech"-- the desirability or not of various proposed rulebooks for determining government responses to speech. The nature of government and law as a sledgehammer influences the outcome of this discussion: it implies we must either smash speech or tolerate it, and that there are few nuances or choices in between.