Fallacy of the Week – Fallacy of Composition

Fallacy of Composition _ the position that what is true of the parts must also be true of the whole, or what is true of the individual members of a group is also true of the group itself.


Matter is made up of invisible particles. Everything is made of matter, therefore everything is invisible.

Both oxygen and hydrogen are flammable. Water is made up of both these flammable elements; therefore water will burn.

If I save money and stop spending, I’ll eventually become wealthy. Everyone can become wealthy by doing the same.

It’s fallacious to assume that what is true of the parts is the same as the whole itself. The properties or functions of the individual parts may not be indicative of the nature of the whole.

However there are exceptions to the rule. Some properties are such that if every part of a whole has the property, then the whole will display those properties.

Example of an exception:

If every piece of the puzzle is plastic, then the puzzle is made of plastic.

Understanding the properties, functionality and relationship of the individual parts to the whole is the key to spotting this fallacy.


Next Week:

Fallacy of the Week – Fallacy of Division


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