Correlation Does Not Equal Causation

Among the easiest logical errors to fall into is to assume that because one event followed another, it must have been caused by the first. That logical fallacy is called post hoc ergo propter hoc, or "after which therefore because of". However equally fallacious is the idea that because two events are related in some way, there is a causal relationship between them, which is, instead cum hoc ergo propter hoc ("with this, therefore because of this"). Succinctly stated:

Because two events are related in some way, does not imply a causal relationship among them.

This sort of fallacy comes up in medical practice and statistics frequently. However, it is just as frequently seen in legal arguments -- and as I've mentioned before, we must keep a watchful eye on both our own arguments and those of our opponents.

I often see the case where because an employee was terminated, and because the employee happens to be a member of a protected class (race, sex, disability, etc.), the employee will raise a discrimination claim. The law and logic require more to prove discrimination (as it turns out, the law and logic share a lot in common): there must also be a correlation between the protected class and the termination. The law calls this correlation a nexus ("bond"), defined as a connection between two things.

As always, contact me for more information.