Reliance on authority leads to falsehood.

One thing that has stuck out to me over the years of reading the great minds in regard to freedom of speech is that Milton had the simple, undeniable position that free speech leads to truth, and that reliance on authority leads to falsehood. Basically, Milton knew that truth can only be discovered through challenge.

Mill went further. This is why I think Mill is more importation.

Mill understood that, even if free speech established a truth, free speech is still valuable in regard to reminding us why we know what we think we already know.

Just think about something as generally accepted as truth as mankind landing on the Moon. Moon landing deniers are among the most ridiculed people on he planet; but, how many of you can prove them wrong without simply pointing to the experts and what you were always told?

I get that you were vindicated in the seventh grade, when your former C student turned science teacher gave you a check plus on a quiz when you correctly checked the box next to the year when he told you the the Moon landing happened. But, what do you do when confronted with somebody who says, "I don't believe this ever happened. I believe that we were lied to in order to gain support against the Soviets. How could a government that is this incompetent get us to the Moon and back? Who was operating the camera when Armstrong supposedly became the first man to walk on the Moon? How did they get those rovers on the Moon in that tiny lander? Why was the flag fluttering with no air?"

There are answers to all of these challenges; but, I would dare to say that most people who ridicule the Moon landing deniers are so bought into convenientional wisdom that they don't know the answers, and probably know less about the subject than the conspiracy theorists.

We know that it's dumb to claim that the earth is flat. How many of you know why it's dumb?

It's dumb and offensive to say that the Holocaust didn't happen. How many of you can prove that it did outside of appealing to authority?

Mills's insight was that truth, when it goes unchallenged, becomes dogma. When that happens, we risk losing the truths that we've gained.