Franco Vazza is a numerical astrophysicist and Associate Professor in the Department of Physics and Astronomy at the University of Bologna, where he runs some of the largest cosmological simulations ever attempted. He studies the cosmic web, extragalactic magnetic fields and clusters of galaxies, and he held a European Research Council Starting Grant for the MAGCOW project on the origin of cosmic magnetism. His work involves building entire simulated universes on supercomputers, testing them against observation, and then deleting them. In 2025 he published a paper in Frontiers in Physics titled Astrophysical constraints on the simulation hypothesis for this Universe, which did what philosophers arguing about the Matrix had never done: it calculated the actual energy bill. The answer, across every version he tested, was numbers so large they are incompatible with the physics of this universe.

Expect to learn what a numerical astrophysicist actually does all day, how you simulate a universe on a supercomputer and why you delete it afterwards, what the simulation hypothesis really claims and where it came from, why Nick Bostrom's 2003 ancestor simulation argument is different from the version people argue about online, how information and energy are physically linked, what Landauer's limit says about the minimum energy needed to flip a single bit, why simulating just the Earth would require converting the mass of an entire galaxy into energy, whether the Grand Theft Auto rendering argument saves the hypothesis, why nobody knows if consciousness is computable in the first place, whether we could ever prove we are simulated, and why Franco thinks certain people have an interest in promoting the idea.

Franco Vazza online:

Website: https://cosmosimfrazza.eu

University profile: https://www.unibo.it/sitoweb/franco.vazza2/en

Mastodon: @[email protected]

Paper: Astrophysical constraints on the simulation hypothesis for this Universe, published open access in Frontiers in Physics

0:00 What a numerical astrophysicist does

2:36 Building a history of the universe

5:01 Why simulations beat observation alone

6:20 Moon rocks and missing evidence

9:35 Existential questions in cosmology

11:13 Tiny fluctuations and cosmic structure

13:07 How much computing power improved

15:23 The limits of current models

17:47 Defining the simulation hypothesis

19:51 Bostrom and the 2003 argument

23:56 The Matrix and popular culture

25:25 Simulating a past civilisation

28:48 Computers, heat and thermodynamics

31:55 Asking how complex a simulation can be

33:48 Calculating the energy cost

35:20 Chaos and the prediction problem

39:48 Landauer's limit and single bits

42:58 Simulating human history

45:04 Neutrinos and low resolution Earth

47:16 Trapping a planet's entire radiation

49:19 The Grand Theft Auto rendering argument

50:51 Reactions to the paper

53:32 Is consciousness computable

54:59 Assuming computers create consciousness

58:17 Why selective rendering fails

59:55 Could we ever prove it

1:01:41 The fundamental gap in the argument

1:03:56 The Pacman hypothesis

1:05:37 Would the answer even matter

1:07:26 Whether we could change anything

1:08:39 Why people were offended by the paper

1:09:54 Elon Musk and the digital blur

Todd K. Shackelford is a Distinguished Professor and Chair of the Department of Psychology at Oakland University in Rochester, Michigan, and one of the most prolific researchers in evolutionary psychology. He earned his Ph.D. under David Buss at the University of Texas at Austin in 1997 and has since published roughly three hundred peer reviewed articles, edited more than a dozen volumes, and accumulated well over ten thousand citations. Much of his work examines sexual conflict between men and women, with a particular focus on sperm competition theory, the idea that when a female mates with more than one male in a short window, the males' sperm compete to fertilize the egg. What began with his astonishment at reading how birds adjust their behavior to the risk of a partner's infidelity became a career studying the same logic in humans, from mate guarding and jealousy to cuckoldry and its psychological aftermath. He is the editor of the journals Evolutionary Psychology and Evolutionary Psychological Science and co directs the Evolutionary Psychology Lab. This conversation ventures into some of the most provocative and uncomfortable territory in the field.

Expect to learn how reading about sperm competition in birds set Todd on his career, what cuckoldry means and where the word comes from, how often men unknowingly raise another man's child, why nature would build psychology to prevent being cuckolded, what mate guarding looks like across species, why men and women are upset by different aspects of infidelity, how obsessive review reveals the sex difference in jealousy, why some men report arousal at the very thing that also enrages them, what a study of adult film covers suggested about sperm competition, whether ejaculate adjustment shows up in the lab, why open relationships run against evolved intuitions, and how the modern cultural meaning of the word cuckold connects to all of it.

Todd Shackelford online:

Website: ToddKShackelford.com

University profile: oakland.edu/psychology

Lab: Evolutionary Psychology Lab, Oakland University

0:00 From New Mexico to evolutionary psychology

4:24 Sperm competition in birds

6:49 Ejaculate adjustment and infidelity risk

8:34 Where the word cuckold comes from

9:46 How often cuckoldry happens

11:33 Why nature evolved to prevent it

15:46 Jealousy, killing, and violence

18:55 Sperm competition theory explained

22:09 Emotional versus sexual infidelity

24:47 Obsessive review and the sex difference

28:04 Arousal from the unthinkable

34:58 Open relationships and evolved logic

36:48 The study of adult film covers

38:40 Ejaculates in the lab

41:00 Inviting rivals and forced copulation

44:22 The female point of view

50:04 Forgiveness and mate value

52:18 The modern meaning of cuckold

55:35 Reality TV and jealousy

1:00:35 The last lab standing

C. Shawn Green is a professor of psychology at the University of Wisconsin, Madison, who studies how people learn and how experience reshapes perception and cognition. As an undergraduate he joined a lab investigating how congenital deafness alters vision, and while testing his measures on a few avid gamer friends he found they scored far above where anyone should, a puzzle that became his senior thesis and launched a career. His work with Daphne Bavelier helped establish that fast paced action video games, particularly first person shooters, can sharpen visual attention, speed of processing, and the capacity to filter distraction. He has spent more than two decades separating hype from evidence, showing that not all games are the same and that the benefits track the specific demands a game places on the brain. His research now spans surgical training, aging and rehabilitation, and the idea that games can teach people to learn new skills faster. He directs the Learning and Transfer Lab and has been cited more than twenty thousand times.

Expect to learn how a testing error on three gamer friends started a whole field of research, why action games improve some cognitive skills but not others, what the correlational versus training study design reveals about causation, how many hours of play it takes to see real effects, why an hour a day beats marathon sessions, what makes the frustrating edge of difficulty the sweet spot for learning, how gaming experience transfers to surgery and piloting, whether games can protect against cognitive decline in aging, why virtual reality still struggles to prove its worth, what a healthy gaming protocol actually looks like, why treating video games as one category is the biggest mistake people make, and how games may teach the deeper skill of learning to learn.

Shawn Green online:

Google Scholar: search C. Shawn Green, University of Wisconsin

University profile: psych.wisc.edu

Lab: Learning and Transfer Lab, UW Madison

0:00 Are you a gamer

0:55 The congenital deafness lab

2:15 Friends scoring off the charts

5:07 When the field began

7:01 Correlational versus training studies

10:01 What the cognitive tests measure

12:09 Why only some skills improve

13:26 Sustained attention and new genres

15:36 The trouble with chess

19:16 How many hours it takes

22:19 The difficulty sweet spot

24:35 Gamers in the operating room

27:53 Bringing the science to work

32:41 Gaming and aging brains

40:38 The problem with VR

46:59 A healthy gaming protocol

51:08 Games are not a monolith

53:25 Learning to learn

59:04 GTA 6 and where to find Shawn

Sven Nyholm is Professor of the Ethics of Artificial Intelligence at LMU Munich and a Principal Investigator at the Munich Center for Machine Learning. Before Munich he taught at Utrecht University and TU Eindhoven, where playing goalie against a soccer-playing RoboCup robot first pulled him toward the philosophy of human-robot interaction. He is co-editor of the journal Science and Engineering Ethics, and his books include Humans and Robots: Ethics, Agency, and Anthropomorphism and This is Technology Ethics: An Introduction. His latest book, The Ethics of Artificial Intelligence, closes with what he calls the AI wager: the idea that society is betting on this technology to solve our problems while gambling with its future. In this conversation he draws on self-driving car fatalities, sex robots, AI companions, and the Richard Dawkins Claude story to think through what happens as machines move into everyday life.

Expect to learn how a game of robot soccer led Sven into robot ethics, why humans anthropomorphize even machines that look like trash cans, what separates pre-programmed factory robots from adaptive AI-powered ones, whether the trolley problem actually applies to self-driving cars, why a death caused by a robot can feel more tragic than one caused by a human, how responsibility and the inability to apologize sit at the center of machine harm, what the Dawkins Claude episode reveals about our hardwired agency detection, why sex robots and AI companions attract both disgust and sympathy, whether embodied robots or text chatbots trigger stronger anthropomorphizing, how frictionless sycophantic AI may erode critical thinking and relationships, what the laziness trap means for children learning with AI, and whether large language models are approaching a plateau.

Sven Nyholm online:
Bluesky: https://bsky.app/profile/svennyholm.bsky.social
LinkedIn: https://www.linkedin.com/in/sven-nyholm-5b8507167/
Book — The Ethics of Artificial Intelligence: https://www.amazon.com/Ethics-Artificial-Intelligence-Philosophical-Introduction/dp/1647922674
All his books (Amazon author page): https://www.amazon.com/stores/Sven-Nyholm/author/B0GTPB6JXB

0:00 Robots beyond the factory

0:43 From robot soccer to robot ethics

4:53 Anthropomorphizing and image recognition

7:18 Classic robots versus AI robots

11:59 The trolley problem and self-driving cars

13:50 From hypothetical to real fatalities

20:19 Why robot deaths feel more tragic

24:33 Responsibility and machines that cannot apologize

30:00 Darwinian buttons and the Dawkins Claude story

33:24 Humanoid robots entering the home

40:37 Sex robots and AI companionship

43:37 His documentary on AI relationships

46:03 Text versus embodied anthropomorphizing

51:53 Frictionless companions and critical thinking

56:44 Kicking robots and human empathy

1:01:09 Unhinged Grok and tuning personality

1:06:25 The AI wager and future outlook

1:11:59 Plateau of large language models

1:19:42 The laziness trap and learning

Kian is a recent graduate of LIU Global and the researcher behind a thesis on loneliness in men. Studying global studies, he was tasked with picking a global issue to research across his whole degree, and he chose loneliness because it was personal to him: he had experienced isolation in school and again later while changing careers and adopting a healthier lifestyle. Drawing on his own time in a men's group he joined at nineteen, he traveled to Bali to conduct three months of fieldwork, interviewing fifteen men who had participated in emotionally open men's groups for anywhere from one year to thirty. From over three hundred codes he distilled five findings, all pointing toward one conclusion: intentionally built men's groups are a viable, sustainable intervention for loneliness. In this conversation, his first ever podcast appearance, he walks through the research, the definition of loneliness, and what actually makes these spaces work.

Expect to learn why loneliness is defined as the gap between the connection you have and the connection you want, how you can feel lonely while surrounded by friends, why youth under eighteen report the most loneliness, what the research says about AI companions alleviating loneliness in the short term, how loneliness can be as harmful to your health as smoking fifteen cigarettes a day, why Kian avoids the phrase male loneliness epidemic, how masculine norms around emotional stoicism keep men isolated, what the five findings from his fifteen interviews actually revealed, why a men's group needs structural safety and confidentiality to work, how vulnerable sharing transforms isolation into connection, what the three pillars of consistency, proximity, and intimacy mean in practice, how the PIES framework helps men figure out what to share, and whether everyone should try joining a men's group at least once.

Kian online:

YouTube: BeinKian

Short film: his film on his loneliness research is on his YouTube channel, with further links in the description

0:00 Why study loneliness in men

1:32 His own experience of loneliness

8:39 Defining loneliness

12:48 Connected yet more disconnected

16:41 AI companions and loneliness

20:16 The health effects of loneliness

22:13 The male loneliness epidemic term

25:42 Masculine norms and emotional stoicism

28:17 The study and Bali fieldwork

35:00 The interviews and main finding

39:09 Finding one: structural safety

43:46 Finding two: a male-only space

47:37 Finding three: isolation into connection

52:55 Findings four and five: belonging and solitude

59:01 Building a good men's group

1:03:49 The PIES framework

1:14:25 Should everyone try it

1:20:19 What's next for Kian

Charlotte Martial is a neuroscientist at the Coma Science Group within the GIGA-Consciousness research unit at the University of Liege in Belgium, where she leads the group's projects on near-death experiences. She studies states of disconnected consciousness, conditions like cardiac arrest and general anesthesia where a person appears unresponsive yet later reports a vivid inner experience, using tools ranging from EEG and MRI to psychedelic models in the laboratory. Trained in psychological sciences with a PhD in biomedical sciences, she has published more than ninety peer-reviewed papers and spent time at the Centre for Psychedelic Research at Imperial College London comparing DMT and ketamine experiences to near-death states. In 2025 she and her colleagues published NEPTUNE, a comprehensive neuroscientific model in Nature Reviews Neurology that tries to explain the phenomenon through the interaction of brain, body, and mind. Her team maintains a database of more than 2,000 experiencers and has recorded brain activity from patients in intensive care in real time. In this conversation she separates the science of dying from belief, and explains what these experiences reveal about consciousness itself.

Expect to learn how scientists first began studying near-death experiences after Raymond Moody's 1975 book, what actually counts as a near-death experience and why the field still lacks a single definition, whether a person has to be truly close to death to have one, why so many people across cultures report peace, tunnels, and out-of-body sensations, how neurotransmitters like noradrenaline and serotonin may generate these features, why the animal behavior of playing dead may be an evolutionary ancestor of the phenomenon, how DMT, ketamine, and other psychedelics are used as safe laboratory models, what happens inside the brain when the heart stops, why consciousness may need only small pockets of brain activity rather than the whole brain, how the life review and precognition resist explanation, and what still stands as the holy grail of near-death research.

Charlotte Martial online:
Email: [email protected]
Instagram: cmartial
Coma Science Group profile: https://www.coma.uliege.be/people/charlotte-martial/
Key paper: A neuroscientific model of near-death experiences, Nature Reviews Neurology, 2025

0:00 Entering the field by chance
3:09 When the science began
5:15 Defining a near-death experience
6:43 Believing you are dying
8:14 Common features across cultures
11:17 The feeling of peace
13:58 The chemistry of dying
16:57 Playing dead in animals
19:25 Science versus belief
21:39 The life review
24:38 Out-of-body experiences
27:32 How the research is done
30:08 Vivid memories of NDEs
32:27 After-effects on life
35:02 Psychedelics, DMT and ketamine
39:04 What the brain does when dying
41:32 Consciousness from small pockets
50:02 Defining consciousness
52:24 Disconnected consciousness
53:40 The open questions
55:52 How her view changed
57:17 A common misconception
59:21 A call for participants
1:00:28 Where to find her

Ian Crawford is Professor of Planetary Science and Astrobiology in the Department of Earth and Planetary Sciences at Birkbeck, University of London, and a self-described child of Apollo who was seven years old when Neil Armstrong stepped onto the Moon in July 1969. An astronomer turned planetary scientist, he came to the field from earlier research on the interstellar medium and now focuses on lunar science, the analysis of Moon rocks, and the search for life in the universe. He has been a co-investigator on lunar instruments flown on missions including ESA's SMART-1 and India's Chandrayaan-1, and he chaired the science team for the C1XS X-ray spectrometer. For more than two decades he has argued the scientific and cultural case for humanity's return to the Moon, work recognised with the 2021 Royal Astronomical Society Service Award and the 2023 Michael J. Wargo NASA Exploration Science Award. In this conversation he lays out why we went to the Moon, why we stopped, and why we are finally going back.

Expect to learn why Apollo really ended and how much of it was Cold War geopolitics rather than science, why it took decades for scientists to realise Apollo did not answer everything, what humans can do on a planetary surface that robots still cannot, how a single Apollo 17 crew outperformed years of modern Mars rovers, whether artificial intelligence and humanoid robots can ever match human explorers off Earth, why the far side of the Moon is the quietest place in the solar system, what it would actually take to build and shield a lunar base, how long astronauts could safely live on the surface, why the Moon is the logical stepping stone to Mars, what we should do if we discover life on Mars, and whether international cooperation could replace a new space race between the United States and China.

0:00 A child of Apollo
2:26 Why we stopped going
6:59 Robots and humans in parallel
9:46 What humans do that robots cannot
12:31 The rover versus astronaut gap
15:10 Apollo 17 in three days
19:31 Humanoid robots and AI
22:14 Energy, latency and AI limits
25:08 Why we are returning now
28:03 Three scientific reasons
33:35 Lunar bases and Antarctica
37:25 Radiation, dust and shielding
41:58 How long astronauts can stay
44:56 The Moon as Mars practice
49:16 If we find life on Mars
56:48 Water, resources and bootstrapping
1:02:01 Geopolitics and cooperation
1:06:28 Where to follow his work

Caroline Goyder is a leading voice and gravitas coach based in the UK and the bestselling author who has trained news anchors, CEOs, actors, and even royalty to speak with confidence. She studied English Literature at Oxford and fell in love with voice and movement at drama school, then spent over a decade as a voice coach at the Royal Central School of Speech and Drama before launching her own practice. An introvert by nature, she built her career on a simple conviction that everyone has a confident speaker within, and that the secret is not performance but regulation, breath, and genuine focus on the other person. Her TEDx talk, The Surprising Secret to Speaking with Confidence, has been viewed more than 10 million times, and in this conversation she revisits it eleven years on after a year training as a breath work facilitator. She is the author of Gravitas and Find Your Voice, and the creator of The Gravitas Method.

Expect to learn why speaking is a physical act rather than an intellectual one, what the human voice offers in an age of AI generated content, why focusing on the other person is the real secret to confidence, what separates a good communicator from a bad one, how fight or flight shows up in your voice when you get nervous, why simplicity is a speaking superpower and so hard to achieve, how the gravitas equation of knowledge plus passion plus purpose minus anxiety works, why too much expertise can work against you, how to bring playfulness to heavy or boring topics, how to stop using filler words and pause with confidence, why a daily breathing practice can change how you show up, what men and women each tend to struggle with, and why introverts can make the most compelling speakers of all.

Wade Allison is an Emeritus Professor of Physics at the University of Oxford and a Fellow of Keble College, where he taught physics and medical physics for over 40 years. He was inspired at the age of 13 in 1954 after stumbling upon the Atoms for Peace exhibition in Geneva, and went on to study at Cambridge and earn his doctorate in particle physics at Oxford and CERN. His research spanned experimental and theoretical physics, but a final-year course he created on the applications of nuclear physics drew him toward radiation safety, where he became convinced that public fear of radiation is wildly out of proportion to the actual risk. He argues that the blast, fire, fear, and panic surrounding nuclear accidents have caused far more harm than the radiation itself, pointing to the survivors of Hiroshima and Nagasaki, the cleanup of Chernobyl, and the panic evacuation at Fukushima as evidence. He is the author of Radiation and Reason and Nuclear is for Life, and the Honorary Secretary of Supporters of Nuclear Energy.

Expect to learn what nuclear energy actually is and how it works, what the three things are that happen when radiation hits living tissue, why the linear no threshold model used to set safety rules is wrong, what really happened to the radium girls who painted glowing watch dials, how a lifetime radiation experiment on dogs revealed a safe threshold, why the fear of radiation was deliberately exaggerated after the war, what the precautionary principle gets wrong, whether a serious nuclear accident could still happen today, why fear and panic do more damage than radiation, how the placebo and nocebo effects can make people genuinely ill, what the Goiania accident in Brazil teaches us, what radiation did and did not do to the survivors of Hiroshima and Nagasaki, why nuclear fuel holds a million times more energy than fossil fuels, and whether nuclear power is really as expensive as people believe.

Wade Allison online:

Website: http://www.nuclear4life.com

Email: [email protected]

Supporters of Nuclear Energy: www.sone.org.uk

Books: Radiation and Reason (2009) and Nuclear is for Life (2015), available on Amazon and all good booksellers

0:00 Introduction

4:41 What is nuclear energy

6:57 Three things radiation does

15:23 The linear no threshold myth

20:59 Chernobyl death data

23:05 Marie Curie

24:54 The radium girls

33:20 Lifetime radiation dog study

41:38 Why the fear was exaggerated

43:19 The precautionary principle

48:06 Could an accident still happen

53:02 The real danger fear and panic

55:56 Placebo and nocebo effects

1:01:34 The Goiania accident

1:07:40 Hiroshima and Nagasaki survivors

1:11:47 Energy density of nuclear

1:14:21 A million times more powerful

1:21:30 Churchill on nuclear energy

1:23:38 Where the energy comes from

1:33:34 The cost of nuclear

1:36:41 China and the future

1:38:56 Closing thoughts

Erik Persson is a Swedish philosopher, an Associate Professor in the Department of Philosophy at Lund University and co-director of its Space Humanities Lab, where his work focuses on the ethics of space exploration. He wrote his doctoral dissertation in environmental ethics and has also studied astrobiology and astronomy, which led him to ask whether the principles we apply to the environment here on Earth can be extended beyond it. His research deals with the moral questions raised by asteroid and lunar mining, planetary protection, terraforming, and the long-term settlement of Mars, and he has published widely on the conflicts between commercial use of space, science, and the possible value of extraterrestrial life. In this conversation he traces how space mining moved from science fiction into a serious geopolitical contest, now that the Artemis programme and a renewed race to the Moon have brought celestial resources within reach. He helps organize a biennial space ethics conference, the most recent edition of which took place at Carnegie Mellon University, with the next planned for Padua, Italy.

Expect to learn what space mining actually means and how mining an asteroid differs from mining the Moon or Mars, why bringing resources back to Earth is rarely worth the energy, how the Artemis programme and China's lunar ambitions have reignited the space race, what the Outer Space Treaty and the Artemis Accords do and do not allow, whether a first come first served approach to space resources is fair, how mining in space could either narrow or widen the gap between rich and poor, what planetary protection is and why we sterilize spacecraft, whether it could ever be ethical to terraform a planet, what we owe to extraterrestrial life if we find it, whether it is right to raise children who never chose to be born on Mars, and why some argue for human settlement of space even when it benefits no one alive today.

Erik Persson Online

Lund University profile: http://fil.lu.se

Popular texts from the Inhospitable Space conference: https://pghrev.com/tag/inhospitable-space-conference-2/

Conference recordings (YouTube playlist): https://www.youtube.com/playlist?list=PLLob6JXdYejvvQA-UERE1qKM1mVZv-LN1

Book recommendation: Mars and the Earthlings: A Realistic View on Mars Exploration and Settlement

Also worth a look: astrobiologist Charles Cockell, who has written on space and liberty.

0:00 Why space mining matters now

0:45 From environmental ethics to space

1:28 Defining space mining

5:41 Who actually benefits

8:55 Mining as substitution not addition

12:21 China and the new space race

15:12 The Outer Space Treaty

15:36 The Artemis Accords

16:11 First come, first served

25:17 The problem with claiming resources

28:59 Settling Mars ethically

32:04 Surviving radiation and environment

40:46 The value of extraterrestrial life

46:44 Why caring about life is hard

48:47 Planetary protection and sterilization

53:22 The ethics of terraforming

55:56 Could Mars become a second Earth

62:57 Raising children on Mars

67:08 Two human species in the system

70:19 The risk to the first settlers

76:03 What is in it for us

79:07 Where to follow Erik's work