Non Causa Pro Causa
Alias: False Cause1
- Cum Hoc, Ergo Propter Hoc
- Post Hoc, Ergo Propter Hoc
- The Regression Fallacy
- Slippery Slope
- Texas Sharpshooter Fallacy
This is the most general fallacy of reasoning to conclusions about causality―see the Subfallacies, above, for more specific causal fallacies. This is why no Example is given since every instance would probably be an example of a more specific fallacy; for an example, see one of the subfallacies, above.
A causal argument is fallacious when it violates the canons of good reasoning about causation in some common or deceptive way. Thus, to understand causal fallacies, we must understand causal reasoning, and the ways in which it can go awry.
Causal conclusions can take one of two forms:
- Event-Level: Sometimes we wish to know the cause of a particular event, for instance, a physician conducting a medical examination is inquiring into the cause of a particular patient's illness, say, lung cancer. Specific events are caused by other specific events, so the conclusion we aim at in this kind of causal reasoning has the form:
Event C caused event E.
- Type-Level: One way to infer causation at the level of events is through the application of causal laws, which have the form:
Events of type C cause events of type E.
Here, we are not talking about a causal relation holding between two particular events, but the general causal relation holding between instances of two types of event. For example, when we say that smoking cigarettes causes lung cancer, we are not talking about an individual act of smoking causing a particular case of lung cancer. Rather, we mean that smoking is a type of event which causes another type of event, namely, cancer. Given a patient who has lung cancer, together with the further information that he was a heavy smoker for many years, we may use the causal law to conclude that his cancer was probably caused by his smoking.
There are three ways that we can be misled about causation:
- Coincidence: Mistakes about event-level causation may be the result of confusing coincidence with causation. Event C may occur at the same time as event E, or just before it, without being the cause of E. It may simply be a coincidence that these two events occurred at about the same time.
- Confounding Causation: Instead of one causing another, two events or event-types may be both caused by a third event or type of event. For example, suppose that you have two clocks in your home, both of which chime the hour at the same time. Does this mean that one clock caused the other to chime? Of course not, as there is a third event that caused both clocks to chime at the same time, namely, your setting both clocks to the same time.
- Reverse Causation: When two events or event-types occur at the same time, we may be tempted to think that one caused the other when the direction of causation is the reverse.
These three ways of going wrong about causation lead to three questions that should be asked about every causal claim:
- Could the occurrence of the two events at about the same time be a coincidence?
- Is there some third event or event-type that could cause both events or types of event?
- If the two events or event-types happen at the same time, could the direction of causation be the reverse?
Only if you can reasonably answer each of these questions negatively should you cautiously conclude causation.
Except in the case of billiard balls bouncing off of one another, it is seldom possible to see what causes what. As a result, it is more difficult to determine causation than many people seem to assume, and a common mistake to jump to conclusions about causation. The news media, in particular, regularly report on scientific studies about health and nutrition as if such studies have established causation, when in fact the authors of the studies deny having done so within the studies themselves3. Consequently, causal fallacies are among the most common and the most damaging logical errors that people make, and much superstition and pseudoscience is the result of people jumping to incorrect causal conclusions.
- This is the usual name given this fallacy, for instance: W. L. Reese calls it: "The Argument from False Cause", see his Dictionary of Philosophy and Religion: Eastern and Western Thought (1980), p. 168. Some authors describe the fallacy as that of inferring that something causes something else when it doesn't, an interpretation encouraged by the fallacy's name and alias―see above. However, inferring a false causal relation is often just a mistake, and it can be the result of reasoning which is as cogent as can be, since most reasoning to causal conclusions is inductive, and therefore the conclusion could be false even if all the premisses are true.
- Translation: "Non-cause for cause", Latin. For the use of this phrase to refer to causal fallacies, see: Peter A. Angeles, Dictionary of Philosophy (1981), p. 98. Alonzo Church, in Runes' philosophy dictionary, uses this phrase for a completely different logical mistake, namely, that of rejecting the wrong assumption in a proof by reductio ad absurdum; see: Dagobert D. Runes, editor, Dictionary of Philosophy (1962), under: "Non causa pro causa". Angeles also appears to mention this same fallacy as a second meaning for the phrase, though his account of the mistake is so brief as to be obscure.
- See The Fallacy Files Weblog for many examples.