Fallacies: C (Part 3)

Core idea

This stretch of the letter C gathers misconceptions that feel like settled knowledge: who Cleopatra was, what cola does to teeth, what a coincidence means, why we catch colds. Each is wrong, and each is instructive. The shared lesson is that confidence is not evidence. A belief can be repeated for centuries, taught to children, and printed in reference books, and still be false — because nobody stopped to test it.

Why it matters

Most of these myths are harmless on their own. Believing a rooster says "cock-a-doodle-doo" universally costs nothing. But the habit of accepting unverified claims is not harmless. The same uncritical reflex that lets "feed a cold, starve a fever" survive also lets quack remedies, conspiracy theories, and bad medicine survive. Practising skepticism on small, safe myths builds the muscle you need for the consequential ones.

Key takeaways

Mental model

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Practical application

Trace the claim to its source

"Cleopatra's Needles" sound Egyptian and connected to Cleopatra — they are neither, having been carved a thousand years before her birth. A label is not a lineage. When a name suggests an origin, check whether the name came from the origin or was attached later.

Distrust the dramatic demonstration

The tooth dissolving in cola is a real demonstration of a misleading point: it ran for 26 hours, far longer than any sip lingers, and the enamel only browned. A vivid experiment can be technically true and practically meaningless. Ask what the demonstration leaves out.

Count, do not marvel

A coincidence is only striking if it is unlikely — and most are not. Crossing letters in the mail happens constantly because relatives often think of each other at once. Before calling something amazing, estimate roughly how often it should happen by chance.

Example

A friend insists their grandmother "always knew" when someone would phone, because the phone would ring just as she mentioned them. It feels uncanny. Count properly: she mentions dozens of people a day, the phone rings several times a day, and she only remembers the hits — never the hundreds of mentions followed by silence. That is not telepathy; it is the birthday-problem logic in everyday clothes. Given enough chances, a "coincidence" is not just possible but expected.

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