Fallacy of Composition

A fallacy of composition arises when one infers that something is true of the whole from the fact that it is true of some part of the whole or even of every proper part of the whole.

This fallacy is often confused with the fallacy of hasty generalization, in which an unwarranted inference is made from a statement about a sample to a statement about the population from which it is drawn.

The converse of the fallacy of composition is the fallacy of division.

Examples

Consider the argument, "This fragment of metal cannot be broken with a hammer, therefore the machine of which it is a part cannot be broken with a hammer." This is clearly fallacious, because many machines can be broken into their constituent parts without any of those parts being breakable.

Here are some other examples of the fallacy of composition:

Atoms are not visible to the naked eye.
Humans are made up of atoms.
Therefore, humans are not visible to the naked eye

You like the taste of ice cream.
You like the taste of scrambled eggs.
Therefore, you like the taste of scrambled eggs mixed with ice cream.

Discussions and Debates

There are also some examples from our forums where members have brought up the fallacy of composition.

Response by Alun in the thread, "If there is a god, why is there evil?"

Questions or comments?

Finally, if you have any questions about the fallacy of composition or wish to debate something about it, please make a post in our Philosophy Forums. Please also post any comments about this page or suggestions of ways to improve it in the feedback section of the forums.