Post hoc ergo propter hoc
Also known as the post hoc, Post hoc ergo propter hoc is a Latin phrase, literally translated as "after this, therefore because of this." It is a fallacious argument that states that because a second event follows the first, the first event must be the cause of the second. Many superstitions are based on this type of argument, because the observer may notice that performing one action seems to lead to another.
Although post hoc observations may lead to a testable hypothesis, there must be evidence of a mechanism that extends the correlation to causation.
My child broke her leg after she was vaccinated, so vaccines cause broken legs.
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