DarkHorse Podcast #305: "Was Darwin Wrong?" — The Evolutionary Lens

Hosts: Bret Weinstein & Heather Heying
Date: December 17, 2025

Main Theme & Purpose

This episode is a deep dive into recent critiques of Darwinian evolution, responding especially to the claim that the evolutionary record fails to account for "body plan" changes (e.g., the appearance of vertebrates from invertebrates). Hosts Bret Weinstein and Heather Heying, both evolutionary biologists, dissect these challenges using their expertise, revisiting the fossil record, evolutionary theory, and why some "gaps" are expected, not damning. The show pivots to a critical look at biotech meat alternatives and the societal implications of drugs like Ozempic.

Key Discussion Points

1. Jim Tour's Critique of Darwinism

Timestamps: 12:57–53:08

• Summary of Tour's Argument (14:20–16:34):

  • Jim Tour (nanotechnology expert, Rice University) claims that while small evolutionary changes ("permutations") are observed, major "body plan changes" are not directly evidenced in the fossil record.
  • Tour contends these transitions (e.g., invertebrates to vertebrates) don't appear as direct, gradual sequences; only as hypotheses drawn from widely-separated fossil discoveries.

• Hosts’ Perspective and Rebuttal:

  • Heather: This line of argument is a familiar one from creationist/intelligent design circles—accepting "microevolution" but denying "macroevolution."
  • Bret: Tour makes more of a concession than most critics, accepting even some between-species evolution, and is worth engaging seriously.
  • They note that evolutionary biology accepts gaps but asserts these are predicted by genuine scientific reasoning, not evidence of failure.

“Everybody accepts the micro evolution at the below species level because you'd be crazy to deny it. The evidence is everywhere and incontrovertible.” —Bret (19:19)

Explaining Fossil Gaps (25:12–53:08)

• Transitional fossils do show up — e.g., Pakicetus, Ambulocetus in whale evolution; Archaeopteryx and other proto-birds; Tiktaalik as transitional tetrapod (33:14–35:03).
• Fossils appear in expected places, disproving some previous "missing link" claims as evidence against evolution.
• The "gaps" often cited by critics are a statistical inevitability due to:
  • Population size and time: Early transitional forms are few in number and exist briefly.
  • Fossilization rarity: Most creatures do not fossilize; extraordinary conditions are required.
  • Rapid evolutionary rates: Major changes are expected to pass quickly through populations, shrinking the window for fossil evidence.

“You would expect almost none of those transitional forms to have walked the earth. Only at the point that the innovation has been refined ... do we expect to see the population grow to a size.” —Bret (44:53)

Bret’s Model and Analogy (37:08–61:15)

• Innovation-Optimization-Diversification Model: Most body plan changes appear as rare and brief "innovations," quickly optimized and diversified in subsequent populations — visualized in Bret’s dissertation trade-off diagram.
• Apple I vs. Apple II analogy: Like early tech prototypes, transitional evolutionary forms are rare and fleeting but essential to later success.

“How many Apple ones were there? The answer is a handful. ... How often would you expect to run into an Apple one in a thrift store versus an Apple II?” —Bret (59:15)

Other Lines of Evidence

• Anatomy, developmental biology, and molecular phylogenetics all independently reinforce the evolutionary narrative, not just fossils.

"The likelihood that these things would line up across multiple domains if the overarching story wasn't right... is strong evidence that Darwin was right." —Bret (54:41)

2. Biotech "Cultured Meat" Critique: Mission Barns’ Cultivated Pork Fat

Timestamps: 61:17–72:46

• Story on Mission Barns, a company growing real pig fat in bioreactors for plant-based meat hybrids.
• Main claims: Pork fat is central to flavor, and this process is supposedly less cruel, more sustainable.

Hosts’ Concerns:

• Safety and Naturalness Skepticism: Bret predicts such products will be "gross" and likely carcinogenic due to necessary tricks (e.g., telomerase to beat the Hayflick limit), possibly leading to tumor-like cells in fat cultures (66:11).
• Sustainability/Practicality Doubts: If repeated animal tissue harvesting is required, it's not scalable or ethical.
• Toxin Accumulation Risk: Animal fat retains fat-soluble toxins; bioreactor environments must be hyper-pure to be safe.
• “Sales Brochure” Journalism: The hosts lampoon the uncritical, glowing tone of such reporting (71:43).

"You're describing growing tumors on the wall and then selling it as if it were food, which isn't any better." —Bret (67:34)

“Eat real meat that's as fresh as possible. Or preserve it well. Jerky’s great—that’s not rotting, it’s preserved.” —Heather (94:03)

3. Ozempic, GLP-1 Drugs, and the “Game of Pharma”

Timestamps: 72:53–94:17

• Background:
  • New article reporting further side effects: besides known impacts (muscle loss, nausea, intestinal issues), recent studies show Ozempic shrinks heart muscle in both lean and obese mice.
  • New anecdotal reports: Users feel flattening of appetite and personality, libido, ambition—chronic anhedonia likened to the emotional blunting of SSRIs.

"By altering their desire for food, some people say they've lost their desire for everything else. What's left is a long lasting state of meh... It's something like the clinical term anhedonia." —Heather, quoting New York magazine (78:40)

• Bret's Pharma Critique:
  • "Game of Pharma": Industry prioritizes profit, using hype to create massive short-term demand (fueled by insurance support and media), knowing side effects will squash long-term usage but maximizing "area under the (profit) curve."
  • Current marketing for “fat cats” shows how pharma extends markets for questionable “solutions” to lifestyle-created problems.
  • They parallel this to vaccine hype and other recent pharma trends: restrict initial access to create demand.

"What you're really looking for is to jack the price up so high that the hype causes people to flood your industry with profit temporarily..." —Bret (87:07)

• Ethical Reflections:
  • Instead of modifying the world around us (portion control, reducing temptation), society increasingly medicates away symptoms, be it in pets or people.
  • The flattening of emotional experience is now seen as an acceptable side effect—“They need breaks from the anhedonia” (from article cited by Heather, 81:57).

Notable Quotes & Memorable Moments

• “Everybody accepts the micro evolution at the below species level because you'd be crazy to deny it. The evidence is everywhere and incontrovertible.” —Bret (19:19)
• "You would expect almost none of those transitional forms to have walked the earth. Only at the point that the innovation has been refined... do we expect to see the population grow to a size." —Bret (44:53)
• "How many Apple ones were there?... How often would you expect to run into an Apple one in a thrift store versus an Apple II?" —Bret (59:15)
• "By altering their desire for food, some people say they've lost their desire for everything else. What's left is a long lasting state of meh..." —Heather, quoting New York Magazine (78:40)
• “They need breaks from the anhedonia, so they occasionally skip a dose or two.” —Heather (81:57)
• “What you're really looking for is to jack the price up so high that the hype causes people to flood your industry with profit temporarily…” —Bret (87:07)
• “Eat real meat that's as fresh as possible. Or preserve it well. Jerky's great—that's not rotting, it's preserved.” —Heather (94:03)

Timestamps for Important Segments

• Intro & Theme Setting: 00:04–10:00
• Jim Tour's Argument & Fossil Critique Discussion: 12:57–53:08
• Innovation-Optimization-Diversification Evolution Explanation: 37:08–61:15
• Analogy to Apple Computers: 58:09–61:15
• Lab-Grown Meat Critique: 61:17–72:46
• Ozempic Side Effects & Societal Implications: 72:53–94:17
• Pharma Business Model & Critique: 83:01–89:29
• Ethics of Medicating Pets & People: 89:29–94:17

Final Takeaways

• Major evolutionary transitions appear rare in the fossil record because they are rare and brief in nature—an expected, not suspicious, pattern given population biology and fossilization odds.
• Overarching evolutionary theory remains robust, strongly supported by converging evidence from fossils, genes, development, and anatomy—even as science continually refines the details.
• Enthusiasm for biotech food and pharma “solutions” to modern problems often outpaces scrutiny of their safety, sustainability, and societal effects.
• The temptation to flatten the highs and lows of existence with pharmacology—whether for vanity, mood, or convenience—carries deep trade-offs that warrant much more skepticism.

For listeners seeking a rich, technical, yet highly accessible look into evolutionary biology, scientific controversy, and the pitfalls of modern "high-tech" fixes, this episode delivers both critical depth and lively wit.