Thefallacy of composition is aninformal fallacy that arises when oneinfers that something is true of the whole from the fact that it is true of some part of the whole. A trivial example might be: "This tire is made of rubber; therefore, the vehicle of which it is a part is also made of rubber." That is fallacious, because vehicles are made with a variety of parts, most of which are not made of rubber. The fallacy of composition can apply even when a fact is true of everyproper part of a greater entity, though. A more complicated example might be: "Noatoms arealive. Therefore, nothing made of atoms is alive." This is a statement most people would consider incorrect, due toemergence, where the whole possesses properties not present in any of the parts.
Thefallacy of composition is related to the fallacy ofhasty generalization, in which an unwarranted inference is made from a statement about a sample to a statement about the population from which the sample is drawn. The fallacy of composition is theconverse of thefallacy of division.
Invoting theory, theCondorcet paradox demonstrates a fallacy of composition: Even if all voters have rationalpreferences, the collective choice induced bymajority rule is not transitive and hence not rational. The fallacy of composition occurs if from the rationality of the individuals one infers that society can be equally rational. The principle generalizes beyond the aggregation via majority rule to any reasonable aggregation rule, demonstrating that the aggregation of individual preferences into asocial welfare function is fraught with severe difficulties (seeArrow's impossibility theorem andsocial choice theory).[citation needed]
Bertrand Russell's example in theCopleston–Russell debate: "Every man who exists has a mother... therefore the human race must have a mother".[1] This was intended to illustrate howcosmological arguments for God's existence (specificallyFrederick Copleston's) commit the fallacy by assuming that the universe itself requires a cause or an explanation for its existence just because everything in the universe does.
"Since every part of a certain machine is light in weight, the machine as a whole is light in weight."[2]
Inchemistry andmaterials science, a single type ofatom may formallotropes with different physical properties from each other, and from their individual constituent atoms, such asdiamond andgraphite each consisting ofcarbon atoms. What is true of a single carbon atom is not true of a collection of carbon atoms bonded into a material. Furthermore, the properties of an atom differ from the properties of the individualsubatomic particles that constitute it.
Insocial network theory, a group of humans arranged into a social network can have abilities not possessed by the individual humans making up the network.[3] A simple example is thebucket brigade, in which humans arranged into a chain can move buckets of water or other similar items across a distance faster and with less effort than can a disorganized group of individuals carrying the loads across the same distance. What is true of the part (an individual needing to move his or her body across the whole distance to move a load) is not true of the whole (in which individuals can move loads across the distance merely by standing in place and handing off the load to the next individual).
"Some people can become millionaires with the right business concept. Therefore, if everyone has the right business concept, everyone will become a millionaire."
Division of labour is another economic example, in which overall productivity can greatly increase when individual workers specialize in doing different jobs. An individual worker may become more productive by specializing in making, say,hatpins, but by satisfying the wants of many other individuals for a given product, the specialist worker forces other workers to specialize in making different things. What is true for the part (earning more by investing in the skills or equipment to make a given product faster) is not true for the whole (because not everybody can profitably make the same product).
In atragedy of the commons, an individual can profit by consuming a larger share of a common, shared resource such as fish from the sea; but if too many individuals seek to consume more, they can destroy the resource.[4]
In thefree rider problem, an individual can benefit by failing to pay when consuming a share of a public good; but if there are too many such "free riders", eventually there will be no "ride" for anyone.[4]
In the economics of education, Bryan Caplan explainscredential inflation, or degree inflation, using the fallacy of composition: "If one person gets a college degree, that person looks more appealing in the labor market. If everyone gets a college degree, everyone will look more appealing in the labor market." (The Case Against Education)
Themodo hoc (or "just this") fallacy is the informal error of assessing meaning to an existent based on the constituent properties of itsmaterial makeup while omitting the matter's arrangement.[5] For instance,metaphysical naturalism states that while matter andmotion are all that composehumans, it cannot be assumed that the characteristics inherent in the elements and physical reactions that make us up ultimately and solely define our meaning; for, a cow which is alive and well and a cow which has been chopped up into meat are the same matter but it is obvious that thearrangement of that matter clarifies those different situational meanings.[5]
^abPigliucci, Massimo (2012). "Chapter 15: On Justice".Answers for Aristotle: How Science and Philosophy Can Lead Us to A More Meaningful Life. Basic Books.ISBN978-0465021383.
^abCarrier, Richard (2005).Sense and Goodness Without God: A Defense of Metaphysical Naturalism. Prometheus Books. p. 130.ISBN1-4208-0293-3.
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