Fallacy of composition: concept, characteristics, examples

The fallacy of composition is the assumption that what is true for one part is true for the rest of the whole. That is, if a part of the whole has a certain property, the whole will be exactly the same.

For example: say that since several elements of a car are made of plastic, the whole car, completely, is made of plastic. The premise is a fallacy because while a car may have some plastic parts (like the dashboard), the rest is made of metal and fiberglass and other materials.

The fallacy of composition is wrongly inferring that a part of the whole fully characterizes the whole. It is a very common type of fallacy in everyday life, and in topics as delicate as religion, the social or the economy. It can be confused with the fallacy of hasty generalization, because the whole is not necessarily the sum of its parts.

Characteristics of the fallacy of composition

This fallacy presents some characteristics by which it can be recognized:

fallacy of irrelevance

The fallacies of irrelevance belong to the type of informal fallacies, that is, they present the error not in its form but in its content, in the information that is given in the premises to infer a conclusion.

In turn, they are classified into another subtype: property transfer fallacies. The fallacy of composition mistakenly transfers the properties of the parts to the complete whole.

Scheme

The scheme that presents the fallacy of composition is the following:

A has parts made up of X.
B is made of A.
So B is X.

The premises can be true or false.

As it is an informal fallacy, the error is not found in the structuring of the arguments, but in the content of what is affirmed. In this sense, a non-fallacious premise can be affirmed as long as the conclusions are valid.

An example: a table is made up of atoms that have mass, therefore the table has mass.

By examining the content of the premise, it can be seen that it is true, since the table is composed of atoms that have mass, and this makes the table itself have mass as well.

Fallacy of composition in economics

The fallacy of composition applied to the economy is very common, and a repeated mistake that some economists and ordinary people make when analyzing certain economic aspects of a society at a certain historical moment.

For example, many people say that raising the minimum wage (in other countries it is called the minimum wage) is a blow to the economy, because it will make small and medium-sized businesses bankrupt by having to face similar expenses.

If that expense cannot be passed on to the consumer, the costs will be higher and the profit margin is reduced. Consequently, the entire economy suffers.

The fallacy of composition occurs in this premise by ensuring that the entire economy will suffer, since it is not taking into account that when people have the capacity to consume, the economy is activated.

In other words, if the population has greater purchasing power, it can generate greater demand for producers. The fact that a group of entrepreneurs has the highest profits is not necessarily always good news, since they will need an audience to which to sell their products.

If there are supplies but not demand, or not enough, it can create an imbalance that can affect the entire economy.

Another case: you live in a third world country and you work online. In your country there is a devaluation of the currency and you are paid in dollars, that means that for the currency exchange you get much more national money than with a «normal» job.

The fallacy of composition here is to say that a further devaluation of the currency improves the overall economy because your home and personal economy improved. It may be true in your case, but for the premise to be true it would require that all the workers in the country were paid in dollars and that the currency was strong.

Fallacy of composition in religion

Religion is another recurring theme for the fallacy of composition. It is not about discussing whether God exists or not (in any of the human representations, be it the Christian, Jewish, Muslim God or in any of the other religions).

For example, saying that God is eternal and that he created the universe, since the universe is not eternal, and that «someone» must have created it, since the universe has not always been present; Since no part of the universe lasts forever, neither does the universe as a whole. Only God.

The fallacy of composition, in matters of religion, is often confused with arguments that are closer to faith and belief than to reason.

Fallacy of composition in everyday life

In everyday life it is more common than we think. For example, when we say that a soccer team, because it has extraordinary players, is an extraordinary team. It is a fallacy because the fact that individually the players are excellent, does not mean that as a team they form an excellent group.

Another everyday case is when we go to the supermarket and hear our mother or father say: «Milk and meat have increased in price, inflation has increased!» The fact that two products have gone up in price does not mean that general price inflation has occurred.

In everyday life we ​​tend to extrapolate our experience to full reality. The fact that something has happened to us does not mean that the same will happen to everyone.

It is a fallacy that promotes prejudices of all kinds and favors the fixation of racial, cultural, ideological stereotypes, etc.

Examples of fallacy of composition

Let’s see several examples of this type of fallacy:

“I was robbed yesterday, and it was an immigrant. All immigrants are thieves.»
The Nazis were mostly German. People who believe that all Germans were or are Nazis commit the fallacy of composition.
When Donald Trump justified the construction of the wall between the United States and Mexico, he used the fallacy of composition based on the premise that «all Mexicans are criminals and drug traffickers.»
“I have spent my holidays in the south of Spain, and the weather is sunny. Consequently, all year round and throughout Spain the weather is sunny”.
“My friends and I want to have children. Ergo, all women want to have children.
“I know five Scandinavians, all five are blond and speak English. All Scandinavians are blond and can speak English.»
The almond contains cyanide, and cyanide is poison. Consequently, the almond is poisonous.

References

Rowe, WL (1962). The fallacy of composition. Taken from jstor.org.
Mixan Mass, F. (1995). Incorrect reasoning: fallacies and paralogisms. Taken from revistas.pucp.edu.pe.
Blecker, RA, Razmi, A. (2010). Export-led growth, real Exchange rates and the fallacy of composition. Taken from auapps.american.edu.
De Lora, P. (2018). Gestar for others: an ultrasound of the fallacies. Taken from dilemata.net.
Rodriguez Jimenez, G. (2021). fallacies. Taken from objetos.unam.mx.