Cum Hoc Fallacy: A Logical Fallacy

Cum Hoc Fallacy: Etymology, Literal and Conceptual Meanings

Etymology

The Cum Hoc Fallacy, also known as the correlation fallacy, is a logical fallacy that occurs when one incorrectly assumes that because two events or phenomena happen simultaneously, there must be a causal relationship between them. The term “cum hoc” is Latin, translating to “with this.” It is derived from the larger Latin phrase “post hoc, ergo propter hoc,” meaning “after this, therefore because of this.” The fallacy emphasizes the importance of distinguishing correlation from causation, as a mere correlation does not imply a causal connection. Understanding this fallacy is crucial in critical thinking and reasoning to avoid drawing unwarranted conclusions based on coincidental relationships.

Literal and Conceptual Meanings

Here is a concise table differentiating the literal and conceptual meanings of the Cum Hoc Fallacy:

Literal Meaning	Conceptual Meaning
Latin term “cum hoc” means “with this”	Fallacious assumption of causation due to simultaneous occurrence
Derived from “post hoc, ergo propter hoc”	Emphasizes the need to distinguish between correlation and causation
Refers to events happening together	Warns against concluding cause-and-effect relationships based on correlation
Highlights the fallacy of assuming causation	Encourages critical thinking and scrutiny of causal claims
Stresses the importance of avoiding unwarranted conclusions	Reminds us to seek additional evidence before asserting causation

Cum Hoc Fallacy: Definition as a Logical Fallacy

The Cum Hoc Fallacy, or correlation fallacy, is a logical error that occurs when one mistakenly assumes a causal relationship between two events solely because they happen simultaneously or in close proximity. It stems from the Latin phrase “cum hoc,” meaning “with this,” and is related to the broader fallacy of “post hoc, ergo propter hoc” (“after this, therefore because of this”). Identifying and avoiding the Cum Hoc Fallacy is essential in critical thinking to prevent drawing unfounded conclusions based on mere correlation.

Cum Hoc Fallacy: Types and Examples

Type of Cum Hoc Fallacy	Description	Example
Synchronicity Fallacy	Assumes a causal connection between two events merely because they happen at the same time, without considering other factors or a direct cause-and-effect relationship.	Example: The rooster crows every morning just before the sun rises. Therefore, the rooster’s crowing must cause the sun to rise.
Confounding Variable Fallacy	Fails to consider other variables that may be influencing both correlated events, leading to a mistaken causal inference.	Example: Ice cream sales and drowning incidents increase during the summer. Concluding that higher ice cream sales cause more drownings without considering the common factor of warm weather.
Reverse Causation Fallacy	Incorrectly assumes the direction of causation, suggesting that Event A causes Event B when, in fact, Event B may be causing Event A.	Example: People who carry umbrellas get wet in the rain. Therefore, carrying an umbrella causes rain.
Coincidence Fallacy	Assumes a cause-and-effect relationship based on a single or a few instances of coincidence, neglecting statistical probability and the likelihood of random occurrences.	Example: A student wears a “lucky” hat during exams and scores well twice. Assuming the hat caused the success, ignoring other factors like preparation.

Cum Hoc Fallacy: Examples in Everyday Life

1. Rooster and Sunrise: Assuming that the crowing of a rooster causes the sun to rise because they happen simultaneously.
2. Superstitions: Believing that wearing a specific item, like a lucky charm, brings good luck simply because positive events occurred while wearing it.
3. Ice Cream and Drowning: Concluding that higher ice cream sales cause an increase in drowning incidents during the summer without considering the shared factor of warm weather.
4. Health Habits: Believing that people who take vitamins and stay healthy do so because they take vitamins, without considering other lifestyle factors.
5. Rain and Umbrellas: Thinking that carrying an umbrella causes rain because it often rains when people are using umbrellas.
6. Traffic Lights and Arrival Time: Assuming that hitting green lights during a commute causes one to arrive at work early, neglecting other factors like traffic conditions.
7. Exam Success and a “Lucky” Pen: Believing that using a specific pen during exams leads to success because it happened a few times, disregarding the importance of preparation.
8. Late-Night Studying and Grades: Thinking that studying late at night causes better grades, without considering the possibility that those who are more disciplined might be more likely to study late.
9. Candlelight and Romance: Assuming that the use of candlelight causes romantic feelings, neglecting the influence of the setting, mood, and personal connection.
10. Wedding Rituals and Marriage Success: Believing that specific wedding rituals or customs directly contribute to a successful marriage, overlooking other factors like communication and compatibility.

Cum Hoc Fallacy in Literature: Suggested Readings

1. Gerald Graff and Cathy Birkenstein, They Say/I Say: The Moves That Matter in Academic Writing, W. W. Norton & Company, 2018.
2. Wayne C. Booth, Gregory G. Colomb, and Joseph M. Williams, The Craft of Research, University of Chicago Press, 2008.
3. John D. Ramage, John C. Bean, and June Johnson, Writing Arguments: A Rhetoric with Readings, Pearson, 2018.
4. Andrea A. Lunsford, John J. Ruszkiewicz, and Keith Walters, Everything’s an Argument with Readings, Bedford/St. Martin’s, 2019.
5. Stephen Toulmin, The Uses of Argument, Cambridge University Press, 2003.