What Don't We Know?

Episode Summary

Executive Summary: A comedy-driven Infinite Monkey Cage episode explores “known unknowns” across physics and biology, contrasting the mysteries of dark matter and dark energy with the unresolved complexity of genetics, consciousness, and evolution. The panel argues that science advances through uncertainty, but also that some questions may remain fundamentally open because reality is far messier than our theories imply.

Main Topics: Known unknowns and the nature of scientific uncertainty (Priority: 5/5): The hosts frame the episode around what scientists know they do not know, arguing that uncertainty is central to science rather than a weakness. Dark matter and dark energy as major cosmological mysteries (Priority: 5/5): Marcus Chown explains that most of the universe is invisible and that dark energy’s discovery upended expectations about cosmic expansion. Why biology remains hard despite genomic breakthroughs (Priority: 5/5): Steve Jones argues that finding relatively few genes in the human genome deepens the puzzle of how complex organisms are built and function. Limits of reductionism and emergent properties (Priority: 4/5): The discussion turns to consciousness, brains, and whether breaking systems into parts can ever explain higher-level phenomena. Humor, philosophy, and the culture of science (Priority: 3/5): The panel uses jokes about clogs, shoes, and philosophy to explore how science differs from dogma and why questioning matters. Audience questions and practical examples of inheritance (Priority: 3/5): Listener questions about thumbs, doorbells, and acquired traits lead to a discussion rejecting Lamarck-style inheritance.

Key Arguments: Science is defined by uncertainty: scientists repeatedly say “I don’t know,” then test ideas until they become more reliable. Most of the universe remains unaccounted for, so cosmology is built on a small visible fraction of reality. Dark energy is a profound anomaly because the best quantum predictions are wildly off from what is observed. Biology may be fundamentally harder than physics because organisms are complex, messy systems with emergent properties. The small number of human genes suggests genes alone cannot explain development, behavior, or complexity. Consciousness may emerge from networks of neurons and synapses, meaning it may not be understandable by reducing the brain to parts. Acquired traits are not inherited in the way people once imagined; repeated tail-cutting in mice did not produce tailless descendants. Physics has a history of overconfidence, so scientists should be cautious about claiming final theories.

Data Points: Universe visible matter fraction: ~4% - Marcus Chown says only about 4% of the universe is made of atoms like those in stars and people. Universe dark matter fraction: 23% - Chown states that dark matter makes up about 23% of the universe. Universe dark energy fraction: 73% - Chown says dark energy accounts for about 73% of the mass-energy of the universe. Share of universe studied directly: ~2% - Chown says science has been studying only about 2% of the universe when combining what is seen with telescopes. Human genes: ~24,000 - Steve Jones says humans have only about 24,000 genes, fewer than expected. Genome sequencing speed: 15 minutes - Jones notes that reading a person’s DNA may soon take about 15 minutes. Original genome sequencing time: 15 years - Jones contrasts future sequencing speed with the 15 years it took to read the first human DNA set. Chemical cost of a human body: 12 pounds, 8 shillings, and 4 pence - Jones cites an old estimate for the chemicals needed to make a human being. Dark energy mismatch: 1 followed by 120 zeros - Chown says quantum theory predicts vacuum energy larger than observed by this factor. Human survival after raw-food diet: within 3 months - Chown claims humans would die within three months on an all-raw-food diet.

Pivotal Quotes: "I don’t feel frightened by not knowing things, by being lost in a mysterious universe without any purpose, which is the way it is, so far as I can tell." — Richard Feynman (quoted by Robin Ince): Used in the opening to frame scientific humility and acceptance of uncertainty. "Science to me, you can define science in one word which is pessimism." — Marcus Chown: He argues that science proceeds by assuming current knowledge may be wrong and testing it repeatedly. "Philosophy is to science as pornography is to sex. It’s cheaper, easier, and some people seem to prefer it." — Steve Jones: Jones uses the line to criticize armchair philosophy and emphasize empirical science.

Implications: The episode reinforces science as a process of disciplined doubt and suggests that some mysteries—especially in cosmology and biology—may require new frameworks, not just more data. For listeners, it highlights humility, skepticism, and the limits of reductionism.