
Hosted by Bruce Nielson and Peter Johansen · EN

In this video podcast, Bruce makes his boldest statement yet about probability. He dives into David Deutsch’s lecture “Physics Without Probability”—as well as our Episode 100 interview with Deutsch—to unpack the core argument.Bruce carefully works through the mathematical details of Deutsch’s claim that probability is merely a “flat-earth approximation.” As best as he can make sense of it, however, the argument just doesn’t add up. In fact, Bruce concludes that Deutsch’s own reasoning seems to imply that probability is not at all comparable to a flat-earth approximation.From there, he methodically explores whether this long-running debate about probability is really a case of word essentialism—an argument over definitions rather than a substantive difference.He closes with an impassioned plea: if someone out there truly understands Deutsch’s argument, please help him pinpoint exactly where he’s going wrong.Support us on Patreon

This week Bruce takes a deep dive into the epistemological ideas in Jonathan Rauch’s book The Constitution of Knowledge. Rauch is a fan of Karl Popper and a former guest on this show. He makes the case that the creation of objective knowledge relies on institutions and norms as much individuals. All claims must be open to criticism and not based on authority. This applies not just to science but to journalism, law, and all areas where humans seek to fallibly move closer to truth. Bruce considers how these claims relate to critical rationalism, specifically Deutsch’s conception of static vs dynamic societies. Does this provide another clue as to why we got stuck in static societies for so many millennia?Support us on Patreon

This week, Bruce looks at how much critical rationalists do—and do not—subject their proposed best theories to critical testing. Bruce wrestles with how we apply the tools of critical rationalism—fallibilism, argument/debate, the demarcation criteria, falsification, and so on—to our real world ideas about economics, politics, and other issues.To do this, Bruce asks these question: Isn't economics famously difficult, or even impossible, to test? Does that mean it is a metaphysical theory? Doesn't Popper's famous demarcation criteria force us to accept that label? And what about Praxeology and Anarcho Capitalism?Support us on Patreon

In our shortest episode ever, Bruce continues his exploration of the concept of concepts by looking at "knowledge" as a concept rather than a theory. And of course along the the way he pushes back again several critical rationalist dogmas.Support us on Patreon

Bruce looks at what makes sense—and doesn’t—about popular theories on knowledge promoted by CritRats (critical rationalists on X). He looks at how much these theories align, and don’t align, with what David Deutsch has actually said about knowledge.Support us on Patreon

A curious Twitter exchange with David Deutsch prompts Bruce to explore what Deutsch and other critical rationalists mean when they assert that randomness doesn’t truly exist.Support us on Patreon

In this episode, Bruce explores his extended conversation with philosopher and inductivist Kieren, focusing on Kieren’s claim that Popper’s Critical Rationalism ultimately depends on induction.Bruce then makes a striking counter-claim: that Kieren’s entire argument amounts to stripping all substantive content from his “theory” of induction and turning it into an unfalsifiable concept—essentially a word game, a kind of argument-by-tautology designed to immunize the theory from criticism. Or put another way, Kieren is turning his theory into a concept because concepts are unfalsifiable.This leads Bruce into a deeper examination of what induction actually is—and what it isn’t. Why is “induction” such a confusing, multidimensional idea? What is the real point of contention between critical rationalists and inductivists? Did Popper truly lack a notion of “support,” as Kieren argues? And what did Popper actually say about justification—did he really reject every form of it?And to make things even more provocative: do CritRats rely on similar linguistic maneuvers to shield their own favored theories from criticism?Support us on Patreon

Here Bruce starts with Popper’s assertion that theories are 100x more valuable than concepts and compares it to Douglas Hofstadter’s ideas on creativity and consciousness. But if concepts matter so little, where do conjectures originate? Popper offers little on this point, yet Hofstadter’s view of the human mind as a system of self-referential feedback loops—able to bridge gaps that formal logic cannot—may provide a useful way to think about it.And while we’re at it, let’s poke at one of the CritRats’ sacred cows: is it actually the case that observations have no role other than helping us pick between rival theories?Support us on Patreon

What is a concept? What is a theory? And was Karl Popper right when he said theories are “100 times more valuable” than concepts? But where do conjectures come from?We go over Popper's own writing about concepts and his explanation for why he feels they are less valuable than theories. Does this prove Bruce wrong from back in episode 112 where he claimed concepts are more valuable than words? What would Popper say?Support us on Patreon

This week Bruce puts Popper on trial. Specifically, through the lens of Michael Stevens’s book, The Knowledge Machine, which argues that science works because it follows the “iron law of explanation” where scientists must (at least in public) put aside philosophy, politics, and theology and only follow empirical evidence. Bruce asks, how compatible is this view with the epistemology of Karl Popper?And does Strevens' critique of Popper ring true? Or is it a strawman?