Thefallacy of division[1] is aninformal fallacy that occurs when one reasons that something that is true for a whole must also be true of all or some of its parts.
An example:
The converse of thisfallacy is calledfallacy of composition, which arises when one fallaciously attributes a property of some part of a thing to the thing as a whole.
If a system as a whole has some property that none of its constituents has (or perhaps, it has it but not as aresult of some constituents having that property), this is sometimes called anemergent property of the system.
The termmereological fallacy refers to approximately the same incorrect inference that properties of a whole are also properties of its parts.[2][3][4][5]
Both the fallacy of division and thefallacy of composition were addressed byAristotle inSophistical Refutations.
In the philosophy of the ancient GreekAnaxagoras, as claimed by the RomanatomistLucretius,[6] it was assumed that the atoms constituting a substance must themselves have the salient observed properties of that substance: so atoms of water would be wet, atoms of iron would be hard, atoms of wool would be soft, etc. This doctrine is calledhomoeomeria, and it depends on the fallacy of division.
Instatistics, anecological fallacy is a logical fallacy in the interpretation of statistical data where inferences about the nature of individuals are deduced from inference for the group to which those individuals belong. The four common statistical ecological fallacies are: confusion between ecological correlations and individual correlations, confusion between group average and total average,Simpson's paradox, and other statistical methods.[7]
