Fallacies: B (Part 1 of 3)

Core idea

The opening of the B-entries collects misconceptions about the body and everyday objects — what bacteria do, where baldness comes from, what would happen if Barbie were real, whether bathing keeps the pores "open." Several are textbook examples of a half-truth promoted to a whole truth. A few species of bacteria cause disease, so all bacteria get treated as enemies; in fact most are harmless and many are essential, breaking down food and crowding out the dangerous strains.

The topic also exposes folk wisdom that simply reverses the facts. Male baldness, the lore says, is inherited "like father, like son" — but the key gene sits on the X chromosome, so it travels through the mother's line. A bagpipe is treated as quintessentially Scottish, yet it is an ancient instrument the Romans knew. The pattern to notice: a belief can be confidently held, neatly worded, and exactly backwards.

Why it matters

Body myths are not idle. The "keep your pores open" claim sold soap on a false premise — pores do not breathe, and the skin's natural oils are a protective layer worth keeping. The bacteria fallacy underwrites a reflex to sterilise everything, when indiscriminate antibacterials can do more harm than good. Acting on a tidy falsehood produces real, if quiet, costs.

These entries also show how a single influential source can seed an error for generations. A popular Victorian schoolbook invented a French etymology for "Beefeaters"; a national water council overstated, then quietly retracted, the water needed to brew beer. The lesson is that authority is not evidence — even a textbook or an official leaflet can simply be wrong, and the correction rarely travels as far as the mistake.

Key takeaways

Mental model

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Practical application

The habit to build here is checking which way the causation runs. The baldness myth is not wrong about heredity — baldness is genetic — it is wrong about the route. Whenever a claim names a cause, ask whether the opposite direction, or a different family member, or a confounding factor, fits the data just as well.

Example

A wellness account claims you should never use antibacterial soap because it "kills the good bacteria your skin needs." Run it through the topic's lens. The kernel is real — skin bacteria do crowd out harmful species. But check the leap: does that make all hand-washing harmful? No; the harmless-bacteria point concerns indiscriminate, body-wide sterilisation, not ordinary washing before a meal. The post has taken a genuine fact (a healthy skin microbiome matters) and promoted it into a sweeping rule (never wash with antibacterial soap), exactly the half-truth-to-whole-truth move that turned a few pathogens into the belief that bacteria as a class are the enemy.

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