What Is the Fallacy of Division? | Definition & Examples

The fallacy of division is the error of assuming that what’s true of a whole must also be true of any given part.

This logical fallacy can occur in arguments that appear logical but don’t hold up to close scrutiny.

Fallacy of division example
“Given Google’s track record of groundbreaking technology, it’s safe to assume that any new product from Google is destined to become a fundamental part of our daily lives.”

This reasoning exemplifies the fallacy of division because it assumes that the success of Google’s product offerings on the whole means that each of its individual products will be successful. In reality, Google has created products that have failed and been discontinued, such as the social network G+ and the augmented reality headset Google Glass.

The fallacy of division can be found in discussions across many domains, such as business, science, and history.

What is the fallacy of division?

The fallacy of division occurs when an argument attributes the qualities of a whole to its individual parts without a clear rationale. The assumption that an entire object, entity, or group has exactly the same traits as its individual components or members often leads to inaccurate judgments.

The fallacy of division is an informal logical fallacy, which means that it is an error of content rather than one of form.

The fallacy of composition is essentially the opposite of the fallacy of division. Fallacies of composition involve making generalizations about a whole based on characteristics of its members or parts.

The ecological fallacy is similar to the fallacy of division. Both involve making assumptions about individuals or components based on characteristics of the whole or group. However, they differ in context:

Ecological fallacy

  • Occurs only in statistical contexts
  • Mistakenly attributes group-level statistics to individual members, overlooking individual variability
  • Involves making inferences about individuals based on aggregate data for a group

Fallacy of division

  • Occurs across various domains
  • Can involve qualitative or quantitative properties (not just statistical data)
  • Involves assuming that properties of a whole must apply to individual parts without sufficient justification

When applied to people, the fallacy of division can sometimes be similar to the guilt by association fallacy, but there is a difference:

  • Fallacy of division: Assumes that all individual members of a group share the same attributes
  • Guilt by association: Maligns a person based solely on their association with another individual or a group of people

Fallacy of division examples

Examples of the fallacy of division can be found in discussions of a wide variety of topics involving living creatures and inanimate objects alike. This fallacy can lead to erroneous conclusions about behaviors, physical attributes, and other characteristics across various fields of study and daily life.

Fallacy of division example in science
In the early stages of atomic theory, it was mistakenly believed that the properties of a material must be directly reflected in the properties of its atoms. This would mean, for example, that because an object made of iron is hard, its individual iron atoms must also be hard.

This line of thinking exemplifies the faulty reasoning of the fallacy of division. In reality, the characteristics of materials arise from complex interactions at the atomic level, not from the inherent qualities of individual atoms.

The fallacy of division can look quite different depending on the context. In a discussion of history, for example, the fallacy of division could be related to assumptions about a historic figure based solely on their civilization and time period.

Fallacy of division example in history
“Ancient Greece was a cradle of philosophy, producing great thinkers such as Socrates, Plato, and Aristotle. This suggests that every individual in Ancient Greece must have been deeply philosophical and engaged in high-level intellectual activities.”This reasoning is a classic example of the fallacy of division because it incorrectly assumes that the intellectual achievements and philosophical advancements of Ancient Greece as a collective were shared equally by all its citizens.

This claim overlooks the diverse society of Ancient Greece, which included not only philosophers but also farmers, artisans, and merchants, many of whom might not have had the leisure to study philosophy.

How does the fallacy of division work?

The fallacy of division typically stems from a genuine misunderstanding rather than an attempt to deceive. It is an error of overgeneralization, which is a common mental shortcut that helps people make decisions quickly and efficiently but can also lead to inaccuracies.

Misunderstanding the distinction between distributive and collective attributes can also lead to the fallacy of division:

  • Distributive attributes: Traits belonging to individual members of a group
  • Collective attributes: Qualities of the group as a whole.

People also tend to overlook the concept of emergent properties: traits or behaviors that are not present in individual parts that emerge from interactions among those parts.

How can you respond to the fallacy of division?

To respond in a constructive way to an argument that commits the fallacy of division, consider the following strategies:

  • Identify the fallacy: Make a habit of noticing when the properties of a whole are assumed to apply to its parts without a logical reason.
  • Question the assumption: Ask for evidence that the properties of the whole apply to its parts, highlighting the need for specific justification.
  • Provide counterexamples: Present examples in which the properties of a whole don’t apply equally to its parts, demonstrating the inherent error in this line of thinking.

Frequently asked questions about the fallacy of division

Are there two forms of the fallacy of division?

The fallacy of division incorrectly assumes that the properties of a whole apply to its parts.

Its counterpart is the fallacy of composition, which assumes that the properties of parts apply to the whole. These are not two forms of the same fallacy but distinct and essentially opposite errors.

The fallacy of division could also be compared to the ecological fallacy, which similarly involves making assumptions about the parts from the whole. However, the ecological fallacy applies strictly to the misuse of statistical data.

What fallacies are similar to the fallacy of division?

The fallacy of division bears similarities to other logical fallacies that involve overgeneralization:

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Magedah Shabo

Magedah is the author of Rhetoric, Logic, & Argumentation and Techniques of Propaganda and Persuasion. She began her career in the educational publishing industry and has over 15 years of experience as a writer and editor. Her books have been used in high school and university classrooms across the US, including courses at Harvard and Johns Hopkins. She has taught ESL from elementary through college levels.