We who live in Western liberal democracies seem to be in a permanent state of angst about who should be allowed to speak and what they should be allowed to speak about.

This angst is acute at the moment, since low-key voices that once represented extreme views on a range of social issues have recently become louder.

Whether it’s US Republican presidential candidate Donald Trump denigrating refugees and talking of banning Muslims from entering his country or Australia’s One Nation leader and senator-elect Pauline Hanson rubbishing climate science and talking of banning Muslims from entering her country, this joltingly aggressive posturing has found traction with voters.

It’s not uncommon to hear people applaud this approach because, after all, they “speak their mind”. But what is so good about speaking your mind if it’s a jumbled mess of self-contradiction?

Even if the stream-of-consciousness ramblings of Trump and Hanson, as two examples, are generally incoherent, could there be any good points worth exploring buried under the intellectual rubble? Either way, should we be listening?

Let me make the case for why these views should be heard, with attention to specific contexts and principles.

You can speak your mind

The German philosopher Immanuel Kant, in his 1784 essay What is the Enlightenment?, wrote of the need for public reason.

He highlighted the desirability for those in the public arena, and particularity those holding or vying for power, to spell out their thinking so that we can make up our own individual minds based on a rational analysis of the case rather than a simple appeal to emotions.

A necessary condition of this is that people not only speak their minds, but must lay out the reasoned argument that leads them to their position. It is the argument, not just the end position, that demands evaluation, for only through this process can we establish the credibility of the end point.

This requirement for a common language of rationality is, we hope, what leads to the best outcomes in the long run. It protects us from leaders acting on whims or in their own interests.

It’s also a bulwark against a world where only shouted slogans and appeals to fear make up the substance of public discourse. A world William Yeats glimpsed in his poem The Second Coming when he wrote of a time in which:

The best lack all conviction, while the worst are full of passionate intensity.

Divergence of opinion, in which people can simply speak their minds, and hopefully their thinking, is desirable. But this divergence must be followed by a phase of convergence in which alternative views are evaluated and consequently progressed or discarded based on collaboratively established norms of effective reasoning.

Each time we hear a poorly argued view, it should further inoculate us against accepting that view.

If arguments for particular positions with relevance to public life ought be exposed to public scrutiny, they must therefore be listened to and seriously engaged with by at least some people some of the time.

Listen for only so long

We do not, however, have the responsibility to elevate a view beyond the point it can attain through its own persuasiveness. Nor are we obliged to keep giving it our attention after its credibility is found wanting.

Appeals for another hearing without fresh arguments or evidence have no inherent right to be further entertained. Such is the nature of debate in young-earth creationism, anti-vaccination advocates or climate change denial, wherein the same old constantly refuted arguments come up again for another desperate gasp of public air.

It is fine to insist that an argument be evaluated on the proving ground of public reason. But it is an offence against that same principle to demand it stay on the playing field once it has been effectively refuted. A sure test of this unwarranted persistence is the degree to which reasoned argument is replaced by tub-thumping, fear-mongering and appeals to the status quo.

People are free to keep saying what they like but, as I have written before, they should not mistake the right to speak with the right to be heard once their case has already failed to convince.

The debate is therefore not silenced, but reaches closure through established, socially moderated processes of analysis and evaluation. All else is cheer-leading in an attempt to convince others that you are still on the field. But the rest of us are entitled to just go home.

Who decides what becomes public?

This all sounds quite rational, but who are the gatekeepers of the public arena? This is a complex issue. In an ideal world, the entry ticket would be a reasoned case in the public interest, but too many box seats have been pre-sold to vested interests.

So we see media companies such as News Corp pushing arguments against climate science that have long been discredited. And across the board news items and personalities that are sensational rather than significant are placed front and centre.

Media coverage of those speaking publicly is always a decision, and it’s a decision that exposes bias. Not just for who is heard, but also for who is not heard.

Take, for example, the claim that moderate Muslims do not speak out against extremism. The plethora of cases in which this does occur are not given a high profile.

We are not obliged to give someone attention, let alone credibility, simply because they are speaking in public. The Enlightenment principles of public reasoning are conditional, and too often these conditions are not met or simply not understood.

But our acceptance and our rejection of views should always be a reflective practice, measured against long-established norms of rationality.

No one should be silenced, but that doesn’t mean everyone needs to be listened to.