He revealed the High Court was considering a “modest” AI trial involving the justices for later this year, and that there would be guardrails over every step of the process.

In a wide-ranging discussion in his Sydney chambers, Gageler said he perceives a “big role” for the chief justice that reflects its place at the apex of the Australian legal system.

He also talked about some “tweaks” in the court’s administration, how the justices are having more meetings as they work on judgments, and his “nuanced” view on whether the court should express a single view.

It is only his second interview since he became chief justice in November 2023, the first being a Q&A with retired New Zealand judge David Collins in January 2024 for Judicature International, which is published by Duke University in the USA.

Gageler said AI would be one of seven issues on the agenda at the Australian Legal Convention, a legal system “summit” involving all federal and state courts at the High Court in November.

“It’s existential.

“It is concerned with artificial reasoning, and essentially - as Sir Edward Coke put it many many years ago - law is artificial reasoning.”

It fell to Coke, as a chief justice, to explain to James I why he should not decide cases himself after he ascended to the British throne in 1603. Coke argued cases should “not to be decided by natural reason, but by artificial reason and reason of law”. (And that keeping the monarch out of disputes was a good thing.)

 “When machines are able to engage in the same form of reasoning as a judge, one wonders, one is forced to interrogate, what is the role of the judge?

“What? Why? Why a human? Why have a human engaged in this process instead of a machine? This is the big question.

“But it's more than that. It's systemic, really, because it also calls into question, I think, the adversarial system.

“So, if you're a plaintiff and you have an AI system formulating your arguments, and there's a defendant who has an AI system formulating the defendant's arguments, is a judge going to have another AI system judging between these two computer generated arguments?

“Or do you have one AI system? I mean, really, it's that big an issue. It really is that big an issue…

“I am not saying any of this is necessarily bad. I'm saying it's a huge challenge.”

Gageler has played out different scenarios in his mind.

“Let's assume you have a large language model that is fed in the data that currently exists in the Commonwealth law reports.

“I have no doubt that even now, a large language model could produce something that looks like a well-reasoned High Court judgment.

“And I have little doubt that either now, or within two years, the predictive power of that large language model will be pretty close, if not surpassing that above an individual judge.

“Let's assume that we get to that point. Let’s say we accept that judgment as being an acceptable judgment of the court.

“Does that get then fed back into the database?”

In a nod to the potential of agentic AI, Gagler disputes the notion that this would stifle development of the law.

“But will it be a computer generated development?

“I mean, at what point does the data set start to include computer-generated outcomes?

Gageler says he does not use AI in his daily work, and says the High Court has “very, very modest thoughts at the moment about potential use.”

“We are going to run a pilot for those members of the court who are interested in the next few months, where we will experiment with using a couple of closed AI programs, limited to our word processing system for editing judgments.

“But we're not going to start that until we’re confident that the programs are appropriate.”

Gageler suggests it might go no further than checking grammar.

“It is not to generate the original script; it is to improve.”

He said the idea came out of discussions with some foreign appellate judges.

“It became apparent that some courts are already doing this, and we thought that we would consider it.

“We're investigating it at a technical level, and we're also going to formulate some guidelines even for the experimentation process.

“There have to be guardrails before you even start.”

Gageler joined the court in 2012, having been a leading silk at the Sydney commercial bar and the Commonwealth Solicitor-General since 2008.

He will have the shortest tenure of any chief justice since Sir Gerard Brennan had only three years (1995-1998) - he turns 70 in July 2028 - but he is no placeholder.

 Gageler agrees that he sees a “big role” for the chief justice.

“Yeah, I do.

“It’s not just being chief justice of the High Court. It is recognising the place of the High Court itself within the Australian judicial system, and recognising the place of the judicial system within the broader constitutional system.

“I see the role of the Chief Justice of the High Court as Sir Garfield Barwick did. On my door in Canberra is the inscription that Sir Garfield Barwick placed there. And the inscription is Chief Justice of Australia. That was the way he conceived of the role and I think he was prescient.

“I think he foresaw a greater cohesion within the Australian judiciary, which didn't exist to the same extent when he was Chief Justice [1964-1981].

“I'm fortunate to arrive at a time when we do have a level of cohesion within the judiciary.”

But Gageler sees room for improvement, which leads to the Council of Chief Justices and the Australian Legal Convention.

Gageler is bemused that the chief justice of the High Court wasn’t even part of the council till it was reconstituted in 1993.

“The New Zealanders were part of it before the High Court was invited.”

He sees a much greater role for the council which he calls “a ready-made forum for sharing of information, coordination of activities.”

The group meets twice a year - but Gageler says there is a lot of work going on behind the scenes. He references a revised guide to judicial conduct, which is being prepared by a working group chaired by former High Court judge Virginia Bell.

He says the “big project” for 2025 is the convention.

“We've got the different parts of the legal system coming together, hopefully talking to each other.

“We want it to be a discussion; talking with each other, rather than being spoken to by others. It’s in the nature of a summit.”

There will be seven sessions across two days - Legitimacy, Artificial Intelligence, Family and Sexual Violence, Institutional Well-Being, First Nations Justice, Access to Justice and Legal Education Training.

Each will have plenary addresses before dividing into workshops, with the chair for each session being a chief justice of a federal or state court.

Gagler will open the convention with the State of the Judicature - the legal equivalent of a “state of the union” address.

The first session will be judicial legitimacy, which Gageler says is “the relationship between the exercise of judicial function and public confidence”.

“It is a relationship that cannot be taken for granted. It's becoming more and more difficult to maintain in a number of comparable jurisdictions around the world.”

Gageler is reluctant to single out the US, saying the situation is more extreme in other countries. But he agrees the legal system there is “facing challenges”.

On a recent visit to the US, he was elected to the council of the American Law Institute until 2030. “It is an organisation whose sole mission is to make American law the best version of itself”.

He notes there are about 850 federal judges in the US, and that in 2023 the average age was 70 - the retirement age of federal judges in Australia.

“When I look at the people I know within the system and when I think of the experience that lies in the system, I think it's going to survive. 

"The judiciary is going to be doing its job, and doing its job with integrity.”

 He said another thing he took away from his visit was an appreciation of Australia’s political system.

“We face the same kinds of pressures that are producing the politicisation of the judiciary. We’re vulnerable to these same forces, but to a much milder extent, because they're moderated by the political system that we are really fortunate to have.

“An independent electoral commission, compulsory voting, preferential voting and for the Senate, proportional voting; put all those things together, and whatever forces of polarisation are out there are moderated in the political outcomes.

“The other thing about our political system is that there's been a long acceptance, in Australia, of the role of the courts on the part of the politicians. Rarely, rarely are courts criticised.”

Only a few days after the interview,  the Federal Government’s Home Affairs Minister, Tony Burke, said the High Court was the reason why he could not place some stateless people with criminal backgrounds in preventative detention.

In its first decision with Gageler as chief justice - NZYQ v Minister of Immigration - the court overturned a precedent that had stood for almost 20 years which allowed the government to detain stateless asylum seekers indefinitely.

It said that detention became punishment - which can only be administered by the courts - when there was “no real prospect of removal from Australia becoming practicable in the reasonably foreseeable future”. This led to the immediate release of more than 150 detainees - and considerable political pain for a government that was taken by surprise by the timing. (The orders were made at the end of the hearing, with the judgment published three weeks later).

A subsequent decision, YBFZ v Minister of Immigration, ruled the government’s response to NZYQ - nightly curfews and ankle bracelet monitors - was also punishment.

Burke said no individual cases had “come close to reaching the threshold” set by the High Court. But he treated it as something he had to deal with, not something to criticise - unlike US President Donald Trump.

“The reality is the legal thresholds that we are stuck with, because of some decisions of the High Court, are more difficult to be able to reach than I want them to be.”

The actual decisions of the court are off limits for discussion, but Gageler says there have been “tweaks” in how it runs and decides cases.

And Gageler himself has changed course, from a puisne justice who was more likely to write alone — especially in big cases to a leader that actively seeks consensus.

In 2018, then chief justice Susan Kiefel said the court was operating differently as part of a “concerted effort to find common ground and reduce the number of individual judgments where justices are largely in agreement”.

Kiefel said the justices had a meeting at the start of each sitting week, at which “points of possible importance might be flagged or preliminary views offered". It might last 30 minutes, but a post-hearing conference would sometimes go well past the hour mark. If they could not agree, the chief justice would convene further meetings.

Gageler said there was now minimal discussion among the justices before a hearing.

“There was a practice some time ago of discussing cases before a hearing. We rarely do that now, unless there is some procedural question to discuss.”

“Any group discussion will have a tendency to cause people to express views.

“My view, and the view of most of my colleagues, is that those discussions, the discussions between the judges about the substance of the case, are much better had after the full argument.”

He says that after a hearing there might be “homework” for the parties.

“That's not uncommon. These days we say ‘you’ve got seven days to provide submissions’. That’s pretty common. Then we have a conference.”

It is not held in the chief justice chambers - as has been the case with previous chief justices - but in the court’s conference room.

“The usual outcome of the conference is the emergence of a majority view.

“The usual end of the conference is with me - as Chief Justice - asking a member of the majority to write a draft.”

Will there be volunteers?

“Sometimes, but generally it will emerge from the discussion [who it will be]

It's not necessarily the most enthusiastic, it's the most appropriate for that case.”

If the judges find it hard to agree, there might be another meeting.

“Sometimes the issues are so complex, or there's enough uncertainty even after the hearing, that we benefit from having one or two members of the court go off and jot down some thoughts, and have another meeting with the benefit of those.”

“If I compare us now with the processes that Chief Justice Kiefel has publicly described, we have less discussion before a hearing, and we have more formal discussion after the hearing.”

He doesn’t seem to share Kiefel’s enthusiasm for the court to “speak with one voice” - or provide a clear majority judgment by multiple justices.

“I have a view, but it’s a fairly nuanced view.

“I see benefit for the profession in producing a single judgment or a single set of reasons for judgment, if that can be achieved without compromising quality.

“Quite often, it can be achieved by narrowing the focus of the judgment and not dealing with things that don't need to be dealt with.

 “If that can be achieved, I'm totally in favor of it.

“But I do recognise that in some difficult areas of law, the different expressions of views on the same legal topic can be of benefit.”

Gageler said he was “not opposed to the concurring judgment” - in which a judge agrees with the majority outcome, but express a divergent view on an aspect of the case.

“Obviously, a dissent is just a different view.

“But if it’s a concurrence, the question is usually raised - why do we have somebody expressing their own views in slightly different words, but coming to the same conclusion?

“If we can come to a common form of expression, or just not deal with issues that divide us - but not really as to the outcome - I prefer to get to a single view.”

There have also been changes in how the court decides which cases to take on. Special leave applications are now usually decided “on the papers” -  without the need for a brief contested hearing on the merits of an appeal.

“The reason we have a hearing is we think there is something to be discussed that is not apparent on the papers. It’s not signifying anything other than we need to discuss this.”

While courts around the country livestream cases, Gageler says the High Court is “not heading in that direction”.

“We take a video and we post it at the same time as we post the transcript (within 24 hours).

“If we were to move to televising hearings, then we would need to have a different system of capturing the image, and then having a time delay.

He said it is “not an access to justice issue”.

“You can attend in Canberra. At the end of the day, you can then get the full audio and visual image at the same time, you get the transcript.

“Probably once every couple of [monthly] sittings, there'll be something said that is a breach of some order for confidentiality.

“I'd rather deal with that at the end of the day, than in the course of the hearing and needing to deal with snipping out part of the transmission.”

Gageler has served with two chief justices - Robert French and Kiefel - but admits to still being surprised by the demands of the job.

 “The workload is significantly greater than I thought.

“A chief justice of a large court [whom he declines to name] told me when I was taking the job that being Chief Justice was about 80% judicial work and about 80% administration. And that's been my experience.

“The amount of time spent on non-judicial work is significantly greater than what I expected.

“Then there’s the engagement with the wider judiciary and the wider world - none of which I regret.”

Gageler has a black belt in taekwondo, but these days yoga is his preferred form of exercise.

“When I became a judge, I decided it wasn’t a good look to be hitting people.”