Well, here is an interesting road I have never travelled before, so let's see where it goes.
I have argued that the right to freedom of speech is not a right to immunity from criticism - even moral criticism - for what one says or writes. It is a right to immunity from violence, including state violence (censorship).
In recent posts I have argued that we can quantify value in terms of willingness to pay under conditions of equal wealth and true belief. Furthermore, moral value is the value of a desire that tends to fulfill other desires (a virtue), or a desire that tends to thwart other desires (a vice).
If we combine these two sets of concepts it would seem to lead to the suggestion that the moral value of a right to freedom of speech can be translated into the value of a universal aversion to the use of violence in response to words written or spoken. In other words, it is what people overall have reason to pay, under conditions of equal wealth and true beliefs, for a state of affairs where people universally to have an aversion to the use of violence in response to words spoken or written.
Now, if we look at the moral arguments for a right to freedom of speech, and remove all arguments grounded on false beliefs (God, intrinsic values, categorical imperatives, impartial observers, social contracts, and the like), we would find that the bulk of those arguments are reasons to pay for a state in which people generally have an aversion to the use of violence in response to words spoken or written.
For example, violence is the weapon of those who hold false beliefs. A person with true and well founded beliefs need not use violence to persuade others of what is true. It is the person with false belief or whose beliefs cannot be supported by evidence who most needs to use violence against alternative ideas. So, prohibiting the use of violence will do more to harm those who are pushing a false belief than those who are promoting truth.
Even if the belief being defended through violence is true, it is better to restrict people to promoting that belief by explaining why it is true. The person who asserts "X is true" because he fears violence need not actually understand "X is true". However, if a person is free to say "X is false" but who asserts "X is true" anyway is more than likely to be somebody who actively believes that However, the person who asserts "X is true" when he has total liberty to assert "X is false" - who adopts it because he is convinced of it and not because he is threatened, understands it and its implications. He can put what he believes to much more efficient use.
There are certainly people who have reason to pay for certain fictions to become widely believed. They have reason to pay to keep some truths hidden. For example, they may lead a religious establishment whose need to protect their interests and influence means suppressing the idea that the institution was built on myth and superstition. And there are businesses who have reason to pay to suppress facts about their products - that they are dangerous or poorly engineered.
However, even these people would discover that, if they had true beliefs, they would have a great many reasons to pay for a universal aversion to violence in response to words written and spoken, because that aversion makes them less likely to be he victim of violence for their own words written or spoken.
They might, after all, be able to convince actual people to side with them on responding to some words with violence. Yet, the question is no whether one has the ability to convince others to use violence as a response o words. The question is whether people with true belief would have a reason to advocate violence as a legitimate response to words.
So what would people overall, with equal wealth and true beliefs, be willing to pay for a state of affairs in which nobody had a desire to rape - or such an aversion to sex without consent that an act of rape would thwart more and stronger desires for each agent than it fulfills?
What would people overall, with equal wealth and true beliefs, have reason to pay for a state of affairs in which no person's decisions are grounded on issues such as the skin color of others - where there is no aversion to dealing with people of one skin color or no desire to deal with people of another skin color?
What would people, with true beliefs and equal wealth, have reason to pay for everybody to want to help those that they see at be at risk of suffering a severe drop in their welfare - a desire to stop and help those who are in need?
The higher this willingness to pay under conditions of true belief and equal wealth, the greater the value of the particular virtue that we are talking about.
Which means that we can quantify moral value - measure it - and make scientific claims as to whether a virtuous person would or would not perform a particular action.
So, now, where does this road lead, I wonder?