
Relatively Human
Season 3, Episode 2: Wrong Parts, Right Answer
Why do some of the most important readings we take barely depend on what's inside a thing?
A living cell runs on a tangle of chemical reactions, yet a model whose 48 rate settings couldn't be pinned down to better than a factor of fifty still predicted what the cells would do, and beat the biologists' own guess. Stranger still, simulations showed that measuring those settings one by one wouldn't have helped. We follow that puzzle through three cases, each harder than the last. A boiling fluid and an iron-fluoride magnet, which share nothing at the level of atoms, come out with the same critical number, 0.327 against 0.325, and we hear how Kenneth Wilson worked out why, one scale at a time. Then Grenoble, two in the morning, 1980: Klaus von Klitzing finds a resistance in an imperfect silicon chip set only by constants of nature and a whole number. Chips of different materials now agree to within about one part in ten billion, and the impurities help make the plateaus. We ask where the claim breaks, when sharper experiments expose what a model left out. Then we follow what that chip changed: the ohm went from a coil of wire sold in a box, and later from cans of wire that slowly drifted, to a recipe the world's standards labs can follow, and in 2019 the kilogram followed. Averaging, stepping up in scale, counting and smoothness each explain part of the pattern, and nobody yet knows whether they are one reason or several. But where a reading doesn't depend on what's inside, you can stop trusting objects and start trusting nature.
Chapters
00:00 Cold open: one claim
02:32 Welcome, and the map of the episode
04:18 Part one: forty-eight settings nobody knew
13:20 Part two: boiling water and a magnet
20:31 Part three: a chip full of flaws
26:44 Where the claim breaks
29:46 From objects to recipes: the ohm and the kilogram
37:48 Why, and what's still open
Keywords: sloppy models, systems biology, renormalization group, critical phenomena, Kenneth Wilson, quantum Hall effect, Klaus von Klitzing, metrology, the ohm, kilogram redefinition
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