Fundamentals of Critical Argumentation by Douglas Walton | Excerpt

The following excerpt about the correlation-causation fallacy is from Professor Douglas Walton's Fundamentals of Critical Argumentation.

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[T]he three main critical questions that should be asked, when an argument from correlation to cause is put forward, are the following.

1. Is there really a correlation between A and B?
2. Is there any reason to think that the correlation is any more than a coincidence?
3. Could there be some third factor, C, that is causing both A and B?

As an example of the third critical question, consider the correlation between drinking red wine every day with a meal and fewer heart attacks among men over forty. Subsequent studies showed that drinking alcohol of any sort (in moderation, meaning one or two drinks per day) was associated with significantly fewer attacks within this group. The latest finding suggested that it was the alcohol in the red wine that caused the outcome and that drinking beer or any kind of alcohol would have the same effect.

In short, argument from correlation to cause is a legitimate and correct type of inference of a presumptive and defeasible type, and it is extremely useful for practical purposes in guiding action in practical matters. But in many cases, there is a natural human tendency to leap too quickly to a causal conclusion once a correlation has apparently been observed. In such cases, it is better to ask appropriate critical questions before placing too much weight on an argument from correlation to cause.

Here is a final word of warning. All arguments based on the statistical claim of a correlation should be questioned regarding how the terms were defined in the survey. The red wine theory of heart disease prevention was recently questioned by a group of cardiologists who pointed out that while most countries require a specific cause of death to be stated, in France, many fatalities caused by cardiac arrest are officially put down to “sudden death.”11 This way of reporting medical statistics would mean that the findings reported would lessen the number of heart attacks.


11 Bernard D. Kaplan, “The Attack on Red Wine’s Hearty Reputation,” Globe and Mail, September 16, 1994, p. A9.


Fundamentals of Critical Argumentation by Douglas Walton
Copyright © 2006 Douglas Walton.  Reprinted with the permission of Cambridge University Press.