Nirvana Fallacy

Logical fallacy

Rejecting a workable option because it falls short of a perfect one. Also called the perfect solution fallacy. The relevant comparison is with the realistic alternative, not with perfection.

An everyday example

“Seat belts don't prevent every death, so there's no point requiring them.”

The same move in this debate

“Veganism doesn't end all animal suffering, so there's no point bothering.”

Where this appears

You can't be 100% vegan, so why try?Ethics & Morality

Rejects a substantial reduction in harm because it falls short of eliminating harm. The comparison that matters is with the realistic alternative, not with a perfect outcome.

Lab-grown meat will solve everythingFood Systems

Holds out for a solution requiring no adjustment at all, and treats the available option as not worth adopting because it asks for one.

Crop agriculture kills animals tooFood Systems

Treats any remaining harm as grounds for abandoning a reduction in it, rather than comparing the two available options against each other.

You can survive on it, but you won't thriveHealth & Nutrition

Treats anything short of theoretically optimal as a failure, a standard that would rule out virtually every diet anyone actually eats, including the one being recommended instead.

Where do you draw the line?Philosophy & Logic

Demands a perfectly precise criterion before any distinction may be acted on, a standard that would disqualify most working categories.