Most people develop opinions about how speech should be restricted via a priori reasoning from abstract principles, often absorbed from primary school civics lessons or other tribal recitations (for example, these days, social media memes).
But in a consequentialist, utilitarian framework, how discourse should be regulated depends on several empirical questions:
- Speech is a physical reality; the speech that occurs in a given medium can be measured.
- The beliefs, behaviors, and harms that a system of speech engenders are also physical realities, and also to some extent measurable.
- The effects of a given mode of speech regulation are also measurable realities.
To put it another way, media are systems with particular mechanics, like games; Twitter is a different game, for example, than Reddit, and both are different from digital journalism or cable news. The mechanics of a medium drive higher-level emergent dynamics, which (for nontrivial systems) can only be studied empirically. The proper instruments of study cannot be drawn from the toolkit of a priori philosophy alone; they require the methods of science and engineering: experimentation, simulation, modeling, comparison of modeling predictions against empirical data.
I posit that any practicing computer game designer could easily design a "speech game" where bad speech totally drives out good. In fact, this would be so easy that the only design challenge would be making it fun enough that anyone would want to play. As a player of that game, you would be a fool to embrace the strategy that "the remedy to be applied is more speech" (quoting Brandeis); you would simply be crushed; your adversaries would laugh at your naivete. I hope this idea seems obvious to you. But are you certain that we aren't all playing such a game in one or more spheres of real life?
It is sad to me that so much effort is spent (wasted!) arguing in totally unproductive circles about some aspect of free speech ("censorship", "cancel culture", "deplatforming", etc.), and so little effort is spent understanding empirically the connection between mechanics and dynamics.