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The One-Way Arrow

This video presents the same text shown beside it, spoken and on screen. It adds nothing the text does not say.

State

The rule arrow runs one way: from established conditions the conclusion may be drawn — and from an established conclusion, nothing follows about the conditions.

Show

A plant can be overwatered without yellow leaves; the rule licensed one direction of travel only.

Watch for

Running an arrow backward is among the oldest reasoning errors in the species — notation, read carefully, is the vaccine.

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