Steelman
Fallacy of composition
Also called composition, part-to-whole fallacy.
Assuming that what’s true of the parts must be true of the whole.
What it is
Inferring that a whole or a group has a property because each of its parts or members has that property.
The pattern
Every part of W has property P. Therefore W has property P.
An example
“Every player on this team is an all-star, so the team will be unbeatable.”
Individual talent doesn’t guarantee teamwork. Teams of stars can lose to better-coordinated sides.
Why it fails
Many properties don’t add up this way. Wholes can have properties no part has (a team’s coordination), and lack properties every part has (each cell is microscopic; a person isn’t).
When it’s not a fallacy
Most lists skip this part. Calling a fair point a fallacy is a mistake too.
It can be fair when
- The property genuinely carries over: if every brick in a wall is red, the wall is red; if every part of a machine is steel, the machine is made of steel.
Try one
A question from the app. The wrong answers are its usual look-alikes.
Lena: “Gas cars are one of the biggest sources of emissions. Phasing them out faster should be near the top of the list.” Mark: “My car puts out about four tons of CO2 a year. The world puts out around 37 billion. Swapping mine for an electric one wouldn’t change anything you could measure. Cars aren’t where climate rules should start. A big coal plant puts out millions of tons a year, so that’s where I’d look first.”
What’s the flaw?
One car really is a rounding error, but Lena’s rule would cover more than a billion of them. Tiny amounts add up: road traffic is one of the largest sources of emissions in the world.
A fair reply
“One car, sure, but the rule is about a billion of them.”
Often confused with
- Fallacy of division
Division runs the other way: from the whole to the parts.
- Hasty generalization
Hasty generalization goes from some members to all members. Composition goes from the members to the group as a single thing.
Where the name comes from
A composition is something put together from parts, like a song from notes or a team from players. The fallacy assumes whatever’s true of the pieces must be true of what they make. “Part-to-whole fallacy” names the direction of the jump: from the parts up to the whole.
Sources
- Fallacies, Bradley Dowden, Internet Encyclopedia of Philosophy
In the app
Practice spotting it on arguments that sound real.
Steelman has more examples of fallacy of composition, how to answer it in a real conversation, and practice rounds that mix it with its look-alikes, so you learn the difference, not just the name. Coming soon to iPhone and Android.
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