Fallacy · Leaning on the wrong support
Sunk cost fallacy
Also called: Throwing good money after bad
Continuing something because of what you have already spent on it, rather than what lies ahead.
What it is
Money, time or effort already spent is gone whatever you choose next. The only sensible question is which choice is best from here. Carrying on just to avoid “wasting” the past usually adds to the waste.
An example
Halfway through a dull film, you stay because you paid for the ticket. The ticket is spent either way; the question is how to use the next hour.
How to spot it
The reason to continue is about the past (“we’ve come so far”) rather than the future.
How to answer it
“If we were starting fresh today, would we choose this?”
When it is not a fallacy
Past effort is relevant when it changes what the future looks like, for example when a project really is nearly finished.
Printable sheet of all fallacies
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A plain reference you can paste into notes or an essay:
Quest2Reason. “Sunk cost fallacy.” https://quest2reason.com/learn/ideas/fallacies/sunk-cost. Accessed 13 November 2026.