Peter Turchin is a complexity scientist and one of the founders of cliodynamics — a new, cross-disciplinary field that applies mathematics and big data to test historical theories.

Full transcript available at: jnwpod.com.

Peter Turchin is a complexity scientist and one of the founders of cliodynamics — a new, cross-disciplinary field that applies mathematics and big data to test historical theories.
Full transcript available at: jnwpod.com.

Well-researched interviews on ideas, technology, and policy. (Plus a recurring series on Australian public policy.)

Well-researched interviews on ideas, technology, and policy. (Plus a recurring series on Australian public policy.)

Joe Walker hosts refreshingly in-depth conversations with founders, scientists, scholars, economists, and public intellectuals.

The Joe Walker Podcast

Joe Walker hosts refreshingly in-depth conversations with founders, scientists, scholars, economists, and public intellectuals.

Peter Turchin — Why Societies Fall Apart (And Why the US May Be Next)

Part 3 of a three-part immigration series this week. Martin Parkinson (economics) available here; Mark Cully (history) available here.

Mike Pezzullo ran the Australian Customs and Border Protection Service (2013-2014), then the Department of Immigration and Border Protection (2014-2017), then the Department of Home Affairs (2017-2023). For more than a decade across those three roles, he was responsible for how Australia selects migrants, screens for risk, and thinks about social cohesion under stress.

We discuss the central but underappreciated fact about how Australia selects migrants: the diversity of our intake is a happy accident of global migration flows, not engineered policy. We also walk through how the visa system actually screens for security and character, why Pezzullo doubts the Bondi terrorist's father would have been refused a student visa in 1998 even with today's tools, what a 2027 China-Taiwan blockade would mean for the Australian migration system in real time, and a never-aired proposal for fixing Australia's "permanent temporaries" problem — a constitutional amendment Pezzullo calls "the Pezzullo special." We finish with: should "populate or perish" return as defence policy? 

(Episode recorded on 16 March 2026.)

Sponsors
Eucalyptus: the Aussie startup providing digital healthcare clinics to help patients around the world take control of their quality of life. Euc is looking to hire ambitious young Aussies and Brits. You can check out their open roles at eucalyptus.health/careers.
Vanta: helps businesses automate security and compliance needs. For a limited time, get one thousand dollars off Vanta at vanta.com/joe. Use the discount code "JOE".

To sponsor a future episode, go to https://josephnoelwalker.com/sponsor/

Part 3 of a <a href="https://josephnoelwalker.com/australias-immigration-blind-spot/">three-part immigration series this week</a>. Martin Parkinson (economics) available <a href="https://josephnoelwalker.com/martin-parkinson/">here</a>; Mark Cully (history) available <a href="https://josephnoelwalker.com/mark-cully/">here</a>.
Mike Pezzullo ran the Australian Customs and Border Protection Service (2013-2014), then the Department of Immigration and Border Protection (2014-2017), then the Department of Home Affairs (2017-2023). For more than a decade across those three roles, he was responsible for how Australia selects migrants, screens for risk, and thinks about social cohesion under stress.
We discuss the central but underappreciated fact about how Australia selects migrants: the diversity of our intake is a happy accident of global migration flows, not engineered policy. We also walk through how the visa system actually screens for security and character, why Pezzullo doubts the Bondi terrorist's father would have been refused a student visa in 1998 even with today's tools, what a 2027 China-Taiwan blockade would mean for the Australian migration system in real time, and a never-aired proposal for fixing Australia's "permanent temporaries" problem &mdash; a constitutional amendment Pezzullo calls "the Pezzullo special." We finish with: should "populate or perish" return as defence policy?&nbsp;
(Episode recorded on 16 March 2026.)
Sponsors
<ul>
<li>Eucalyptus: the Aussie startup providing digital healthcare clinics to help patients around the world take control of their quality of life. Euc is looking to hire ambitious young Aussies and Brits. You can check out their open roles at <a href="https://www.eucalyptus.health/careers">eucalyptus.health/careers</a>.</li>
<li>Vanta: helps businesses automate security and compliance needs. For a limited time, get one thousand dollars off Vanta at vanta.com/joe. Use the discount code "JOE".</li>
</ul>
To sponsor a future episode, go to https://josephnoelwalker.com/sponsor/

How Australia Actually Selects and Integrates Migrants — Mike Pezzullo [Immigration Series]

Part 2 of a three-part immigration series this week. Martin Parkinson (economics) available here; Mike Pezzullo (acculturation, social cohesion, security) drops Friday.

Mark Cully was the inaugural chief economist at the Australian Department of Immigration (2009-2012). His forthcoming book, Waves of Plenty (September 2026), is (to my knowledge) the first truly general history of immigration to Australia. It will fill a remarkable gap in our literature, given the centrality of immigration to the Australian story.

We discuss Australian exceptionalism in migration policy. The only country to have run assisted passage at scale (around 3.5 million people whose fares were subsidised). The first country in the world to have a dedicated Department of Immigration. The first country to offer migrants English-language training. Per capita, the world's largest receiver of international students for decades. Today, one of only three countries – alongside Switzerland and Singapore – with an overseas-born share above 30%. On current trends that share is projected to approach 40% by mid-century, a level likely not seen since the 1880s.

We walk through six decades that built the nation – the 1830s, 1850s, 1890s, 1950s, 1970s, and 2000s. We discuss why Australia eschewed slavery, why the 1850s might be the most important decade in the making of modern Australia, and what the White Australia policy was really about. We also explore what made the post-war migration program the most epic policy experiment in our history, whether migration has increased Australian living standards, and what history can teach us about the rise of One Nation.

(Episode recorded on 23 February 2026.)

Sponsor
Vanta: helps businesses automate security and compliance needs. For a limited time, get one thousand dollars off Vanta at vanta.com/joe. Use the discount code "JOE".

To sponsor a future episode, go to https://josephnoelwalker.com/sponsor/

Part 2 of a <a href="https://josephnoelwalker.com/australias-immigration-blind-spot/">three-part immigration series this week</a>. Martin Parkinson (economics) available <a href="https://josephnoelwalker.com/martin-parkinson/">here</a>; Mike Pezzullo (acculturation, social cohesion, security) drops Friday.
Mark Cully was the inaugural chief economist at the Australian Department of Immigration (2009-2012). His forthcoming book, <a href="https://amzn.to/4dAaAZr">Waves of Plenty</a> (September 2026), is (to my knowledge) the first truly general history of immigration to Australia. It will fill a remarkable gap in our literature, given the centrality of immigration to the Australian story.
We discuss Australian exceptionalism in migration policy. The only country to have run assisted passage at scale (around 3.5 million people whose fares were subsidised). The first country in the world to have a dedicated Department of Immigration. The first country to offer migrants English-language training. Per capita, the world's largest receiver of international students for decades. Today, one of only three countries &ndash; alongside Switzerland and Singapore &ndash; with an overseas-born share above 30%. On current trends that share is projected to approach 40% by mid-century, a level likely not seen since the 1880s.
We walk through six decades that built the nation &ndash; the 1830s, 1850s, 1890s, 1950s, 1970s, and 2000s. We discuss why Australia eschewed slavery, why the 1850s might be the most important decade in the making of modern Australia, and what the White Australia policy was really about. We also explore what made the post-war migration program the most epic policy experiment in our history, whether migration has increased Australian living standards, and what history can teach us about the rise of One Nation.
(Episode recorded on 23 February 2026.)
Sponsor
<ul>
<li>Vanta: helps businesses automate security and compliance needs. For a limited time, get one thousand dollars off Vanta at vanta.com/joe. Use the discount code "JOE".</li>
</ul>
To sponsor a future episode, go to https://josephnoelwalker.com/sponsor/

"Bigger and Different": The Six Decades That Remade Australia — Mark Cully [Immigration Series]

Part 1 of a three-part immigration series this week. Mark Cully (history) drops Thursday; Mike Pezzullo (acculturation, social cohesion, security) drops Friday. 

 Martin Parkinson ran the Australian Treasury (2011-2014), then the Department of Prime Minister & Cabinet (2015-2019). He's also thought deeply about the economics of migration policy, not just in those roles, but also in his past academic life and as chair of the Australian government's 2023 Migration Review (the most significant review of our migration system in more than three decades). 

We discuss the central but underappreciated issue with Australian migration policy today: we've drifted into a quasi-guest-worker system without anyone voting for it. About 2.3 million people in Australia now go to sleep here every night with work rights, but without being citizens or permanent residents. 

We also work through how migration affects living standards, the "Soviet-style" occupation list that governs our skilled program, how to attract true global talent, how international student fees came to subsidise roughly half of Australian university research, and what should be the upper and lower bounds for net migration. We end up in an unexpected place: how much more geopolitical weight would a larger population actually buy us?

(Episode recorded on 27 February 2026.)

Sponsors
Eucalyptus: the Aussie startup providing digital healthcare clinics to help patients around the world take control of their quality of life. Euc is looking to hire ambitious young Aussies and Brits. You can check out their open roles at eucalyptus.health/careers.
Vanta: helps businesses automate security and compliance needs. For a limited time, get one thousand dollars off Vanta at vanta.com/joe. Use the discount code "JOE".

To sponsor a future episode, go to https://josephnoelwalker.com/sponsor/

Part 1 of a three-part immigration series this week. Mark Cully (history) drops Thursday; Mike Pezzullo (acculturation, social cohesion, security) drops Friday. &nbsp;Martin Parkinson ran the Australian Treasury (2011-2014), then the Department of Prime Minister &amp; Cabinet (2015-2019). He's also thought deeply about the economics of migration policy, not just in those roles, but also in his past academic life and as chair of the Australian government's 2023 Migration Review (the most significant review of our migration system in more than three decades). We discuss the central but underappreciated issue with Australian migration policy today: we've drifted into a quasi-guest-worker system without anyone voting for it. About 2.3 million people in Australia now go to sleep here every night with work rights, but without being citizens or permanent residents. We also work through how migration affects living standards, the "Soviet-style" occupation list that governs our skilled program, how to attract true global talent, how international student fees came to subsidise roughly half of Australian university research, and what should be the upper and lower bounds for net migration. We end up in an unexpected place: how much more geopolitical weight would a larger population actually buy us?
(Episode recorded on 27 February 2026.)
Sponsors
<ul>
<li>Eucalyptus: the Aussie startup providing digital healthcare clinics to help patients around the world take control of their quality of life. Euc is looking to hire ambitious young Aussies and Brits. You can check out their open roles at <a href="https://www.eucalyptus.health/careers">eucalyptus.health/careers</a>.</li>
<li>Vanta: helps businesses automate security and compliance needs. For a limited time, get one thousand dollars off Vanta at vanta.com/joe. Use the discount code "JOE".</li>
</ul>
To sponsor a future episode, go to https://josephnoelwalker.com/sponsor/

Peter Turchin — Why Societies Fall Apart (And Why the US May Be Next)

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