"Post hoc, ergo propter hoc" is Latin for "after this, therefore because of this." It is used to refer to the logical fallacy of assuming that because one event follows another it was also caused by it. For example: "I thought of my brother, and then, like, two seconds later he phoned me. He must have felt my aura and responded to me." Or, less fancifully, but equally flawed: "The rooster cock 'a doodled and the sun rose. Therefore, the rooster's sound must have caused the sun to rise."

Sometimes an event happens after another event coincidentally, and the two have nothing to do with each other. The mere fact of proximity in time should not be taken as sufficient proof of a cause-and-effect relationship, because it ain't.

At other times, a number of partial causes lead to an effect, but one is selected as the sole cause. This is called "oversimplification of the cause," and it is also flawed thinking. We can't establish what is actually the case solely by reference to when things happen. So long as you don't fall into thinking that you can thusly establish things, you won't commit the post hoc, ergo propter hoc fallacy.

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