In the 16th century, witches and demons weren’t just for Halloween. People were terrified and preoccupied with them – even kings.

In 1590, James VI of Scotland – who was later also crowned James I of England – travelled by sea to Denmark to wed a Danish princess, Anne. On the return journey, the fleet was hit by a terrible storm and one of the ships was lost.

James, a pious Protestant who would go on to sponsor the translation of the King James bible, was convinced he’d been the target of witchcraft. A few years later, James decide to write a treatise called Daemonologie, setting out his views on the relationship between witches and their master, the devil.

Meanwhile, another firm Halloween favourite – ghosts – had fallen out of favour in the wake of the Protestant Reformation because they were seen as a hangover from Catholicism.

In this episode, Penelope Geng, an associate professor of English at Macalester College in the US who teaches a class on demonology, takes us back to a time when beliefs around witches, ghosts and demons were closely tied to religious politics. She explains how these beliefs have come to influence the way witches and ghouls have been portrayed in popular culture ever since.

This episode was produced by Mend Mariwany and Katie Flood with mixing by Eleanor Brezzi. Theme music by Neeta Sarl. Gemma Ware is the executive producer. Read the full credits for this episode and sign up here for a free daily newsletter from The Conversation.

If you like the show, please consider donating to The Conversation, an independent, not-for-profit news organisation.

• From printing presses to Facebook feeds: What yesterday’s witch hunts have in common with today’s misinformation crisis
• Samhain: the true, non-American origins of Halloween
• What’s the difference between ghosts and demons? Books, folklore and history reflect society’s supernatural beliefs

One American company called Strategy owns more than 3% of all bitcoin in existence. In August 2020, its executive chairman, Michael Saylor, pioneered a new business model where publicly listed companies buy cryptocurrency assets to hold on their balance sheet.

More than 100 other public companies have since followed Saylor’s lead and become bitcoin treasury companies, together holding more than $114 billion of bitcoin. There’s been a new rush into crypto treasury assets in 2025 following the general crypto enthusiasm of the new Trump administration.

But holding bitcoin assets also comes with some big risks, particularly given the volatility of cryptocurrency prices, and the share prices of some of these companies are now coming under pressure.

In this episode, we speak to Larisa Yarovaya, director of the centre for digital finance at the University of Southampton in the UK, about whether bitcoin treasury companies are the future of corporate finance, or another speculative bubble waiting to burst.

This episode was produced by Mend Mariwany and Gemma Ware with assistance from Katie Flood. Mixing by Michelle Macklem and theme music by Neeta Sarl. Read the full credits for this episode and sign up here for a free daily newsletter from The Conversation.

If you like the show, please consider donating to The Conversation, an independent, not-for-profit news organisation.

• Cryptocurrency’s transparency is a mirage: New research shows a small group of insiders influence its value
• Bitcoin: why a wave of huge companies like Tesla rushing to invest could derail the stock market
• Could digital currencies end banking as we know it? The future of money

As one of the birthplaces of the industrial revolution, the River Mersey in northern England is no stranger to pollution flowing into its waters. Now it's got a new problem: monitoring shows the amount of forever chemicals, also known as PFAS, entering the Mersey catchment area is among some of the highest in the world.

In this episode we speak to water scientist Patrick Byrne at Liverpool John Moores University in the UK about why so many per- and polyfluoroalkyl substances (PFAS), are still making it into our rivers, many from sources that are lying hidden. Identifying these sources of pollution, can help prioritise how to clean them up.

This episode was produced by Mend Mariwany, Katie Flood and Gemma Ware. Sound design and mixing by Michelle Macklem and theme music by Neeta Sarl. Read the full credits for this episode and sign up here for a free daily newsletter from The Conversation.

If you like the show, please consider donating to The Conversation, an independent, not-for-profit news organisation.

• You can be exposed to PFAS through food, water, even swimming in lakes – new maps show how risk from ‘forever chemicals’ varies
• Australia has banned 3 ‘forever chemicals’ – but Europe wants to ban all 14,000 as a precaution
• How I tracked the biggest hidden sources of forever chemical pollution in UK rivers – new study

Back in the 1980s, when Shimon Sakaguchi was a young researcher in immunology, he found it difficult to get his research funded. Now, his pioneering work which explains how our immune system knows when and what to attack, has won him a Nobel prize.

Sakaguchi, along with American researchers Mary Brunkow and Fred Ramsdell, were jointly awarded the 2025 Nobel prize in physiology or medicine for the work on regulatory T-cells, known as T-regs for short, a special class of immune cells which prevent our immune system from attacking our own body.

In this episode Sakaguchi tells The Conversation about his journey of discovery and the potential treatments it could unlock.

This episode was produced by Mend Mariwany, Katie Flood and Gemma Ware. Sound design and mixing by Michelle Macklem and theme music by Neeta Sarl. Read the full credits for this episode and sign up here for a free daily newsletter from The Conversation.

If you like the show, please consider donating to The Conversation, an independent, not-for-profit news organisation.

• Metal-organic frameworks: Nobel-winning tiny ‘sponge crystals’ with an astonishing amount of inner space
• Nobel physics prize awarded for pioneering experiments that paved the way for quantum computers
• How does your immune system stay balanced? A Nobel Prize-winning answer
• Nobel medicine prize: how a hidden army in your body keeps you alive – and could help treat cancer

As Donald Trump gives oxygen to unproven theories about what might be behind a recent rise in autism cases, experts repeatedly point to the changing nature of how autism is diagnosed and viewed.

A key moment in the history of autism diagnosis was the publication in 1994 of a new version of the Diagnostic and Statistical Manual of Mental Disorders. It's a reference book of psychiatric conditions and how to diagnose them, used by psychiatrists and psychologists around the world.

In this episode, Andrew Whitehouse, a professor of autism research at the University of Western Australia, explains why this shift in autism diagnosis happened in the 1990s, what impact it had, and what it's meant for the support autistic people get.

This episode was produced by Katie Flood, Mend Mariwany and Gemma Ware. Sound design and mixing by Michelle Macklem and theme music by Neeta Sarl. Read the full credits for this episode and sign up here for a free daily newsletter from The Conversation.

If you like the show, please consider donating to The Conversation, an independent, not-for-profit news organisation.

Donald Trump is not letting up pressure on the US Federal Reserve. He's taken efforts to fire one of its governors, all the way up to the US Supreme Court.

Trump's clash with the Fed echoes pressure that Richard Nixon put on the central bank in the 1970s to lower interest rates. In this episode, Cristina Bodea, professor of political science at Michigan State University, why that moment – and the inflation spike that followed – became a cautionary tale about what can happen if politicians threaten the independence of central banks.

This episode was written and produced by Katie Flood and Gemma Ware with assistance from Mend Mariwany. Sound design and mixing by Eloise Stevens and theme music by Neeta Sarl. Read the full credits for this episode and sign up here for a free daily newsletter from The Conversation.

If you like the show, please consider donating to The Conversation, an independent, not-for-profit news organisation.

With France, the UK, Australia and Canada expected to recognise an independent Palestinian state at UN General Assembly in New York, what are the origins of the state they plan to recognise?

In this episode, Palestinian-American historian Maha Nassar from the University of Arizona describes the events leading up to the original declaration of Palestinian independence in 1988, including the compromises made within the Palestinian liberation movement. Nassar then traces how  we've got to the point where more than 150 countries will recognise an independent Palestinian state – a move that she believes is more of a symbolic gesture than a meaningful route to Palestinian sovereignty.

This episode was written and produced by Mend Mariwany and Gemma Ware with assistance from Katie Flood. Sound design and mixing by Eloise Stevens and theme music by Neeta Sarl. Read the full credits for this episode and sign up here for a free daily newsletter from The Conversation.

If you like the show, please consider donating to The Conversation, an independent, not-for-profit news organisation.

Police in Australia are continuing a huge manhunt in the mountains for Dezi Freeman, a man accused of killing two police officers and injuring a third in late August.

Freeman identifies as a sovereign citizen, someone who believes they aren't subject to the law.

In this episode we speak to criminologist Keiran Hardy from Griffith University about the origins of the sovereign citizen movement in the US, how it spread to Australia and was taken up by the self-styled Prince Leonard in the 1970s, and why the movement grew during Covid-19.

This episode was written and produced by Mend Mariwany and Gemma Ware with assistance from Katie Flood and editing help from Ashlynee McGhee. Sound design and mixing by Eloise Stevens and theme music by Neeta Sarl. Read the full credits for this episode and sign up here for a free daily newsletter from The Conversation.

If you like the show, please consider donating to The Conversation, an independent, not-for-profit news organisation.