I’ve met Malcolm Roberts. Not him exactly, but one of the inevitabilities of being a lawyer is that you get to meet lots of people like Malcolm Roberts. The key to understanding them isn’t so much in the overtly insane counter-factuals they postulate without ever seeming to blink, entertaining as they are. There’s a more significant clue.

It’s hardly surprising that a One Nation Senator believes NASA is leading a worldwide conspiracy to falsify climate records. There was no reason for the ABC not to give Roberts a platform on Q&A, given that he will hold part of the balance of power for the next few years at least. We should all hear his theories in their full glory. It was, however, surprising to see someone as smart and savvy as the physicist Brian Cox fall so easily into the trap of arguing with a person like that on rational grounds.

Bad idea. You don’t follow the Mad Hatter down the rabbit hole unless you want to find yourself questioning your own sanity. We don’t debate with cancer, nor should we with delusion.

[Malcolm Roberts: the One Nation climate denier too out there for Andrew Bolt]

One interchange during Q&A in particular gave me some powerful deja vu. The question for the panel was about Bill Leak’s provocative/racist cartoon in The Australian in response to the Don Dale scandal. When his turn came, Roberts saw his opening for one of the things he’s been badly wanting to say on national television. After explaining how brave he considers Leak to be, the conversation went in this direction:

ROBERTS: Now, [there’s] something else that’s really important for me and that is that this kind of legislation, this kind of curbing of free speech leads to this. [Holds up a letter] This is one of my constituents in Queensland. He says “One LGBT activist in NSW has lodged at least 28 complaints against me because he disagrees with my views on marriage and morality, including one complaint that I have incited hatred by linking to an Andrew Bolt article on Facebook. I have moved my family after this activist offered to release my address to Islamic organisations. He also conspired with others to lodge complaints in order to seize my house. This abuse occurs because the New South Wales — New South Wales — Anti-Discrimination Board fails to investigate complaints. It is …”

TONY JONES:  I’m going to have to get you to go to the last sentence, or something, because it could be a very long letter …

ROBERTS: The point I am getting to is that this man is being intimidated in Queensland by a NSW Anti-Discrimination Board that is working on an activist perpetrating 28 complaints that are basically nonsense.

AUDIENCE: [Silence]

JONES: O-kay. Umm…

I’ve had the same conversation literally scores of times. You’d be very surprised, trust me, by the reality of how many people in the community are living personal paranoiac nightmares like Roberts’ correspondent from Queensland. In the law, we call them “vexatious litigants” and other less flattering terms.

They can be difficult to detect at first glance. Like Roberts himself, they are consumed by the crucial importance of the stories they need to tell. This gravity clothes them with a superficial appearance of rationality. They are armed with extraordinary levels of detail: documents that “prove” their case; a seemingly perfect recall of every relevant event and circumstance. At the base of their story is usually a cause that engages an empathic response, some (at least sincerely imagined, if not real) trauma or invasion of rights.

Many years ago, I encountered a young man who had, by then, spent over a decade in the courts of NSW pursuing compensation for the back injury he had allegedly incurred when he slipped and fell on his first day of work at a petrol station. He’d sued the owner but recovered nothing when the defendant declared bankruptcy. He then sued his lawyers for negligence. When we got involved, our firm was the 35th he had engaged. He sued us too. When we lost sight of him another decade later, he was well past his 60th set of lawyers and still going strong. I knew of at least 20 separate cases to which he was a party, in every court possible, including the High Court, all arising from the original personal injury claim.

This man was intelligent, resourceful, encyclopaedically knowledgeable about his own case and, on first meeting, apparently sane — just a victim of injustice in a legal system that is so often an exceedingly blunt tool. In reality, he was entirely consumed by his legal cause, which became his single-minded obsession. He was paranoid, delusional, amoral and potentially dangerous. Apart from destroying his own life, he absorbed unbelievable volumes of public resources as he clogged up the court system with his ever-expanding litigation.

The tell-tale signs of the same detachment from rationality are present in Roberts’ Q&A detour. His constituent’s story is as impenetrably nonsensical to lawyers as it is to anyone else. One of the unintended consequences of a system of open justice is that it lends itself perfectly to people who have an axe to grind and an absence of perspective. Conspiracy, which almost never actually exists but is always a ready explanation for life’s habit of sometimes sucking, is in the law hypothetically real. Every obsessed litigant knows that the smoking gun that will win their case is out there, and they’re always just one tactical manoeuvre short of discovering its hiding place.

[Pauline Hanson’s merry band]

Roberts is, obviously, a conspiracy theorist. We’ll be hearing more from him about the UN’s black helicopters and how governments control us with grammar. But we’ll hear even more stories like that of the Queenslander who nearly lost his house to the NSW Anti-Discrimination Board (a body that does exist but which has no powers to do anything other than investigate and try to resolve complaints). Roberts likely has a garage full of them.

Paranoia is a debilitating condition. It causes a construction of the world like a building full of mirrors but no doors; everything reflects back onto a central, all-explaining but eternally elusive truth, the revelation of which is a desperate, endless itch.

Malcolm Roberts is a senator, for better or worse. Like his leader, he need not engage our sympathy or empathy; he placed himself and his peculiarities in the public eye. We’re entitled to assess and judge him on what he says and does. He’s going to say some crazy shit. He isn’t funny, any more than Pauline is funny, so don’t laugh. But, equally, don’t take the bait. We’ll never argue him down, because his world isn’t ours. The only appropriate response is “O-kay. Umm …”