What is the difference between the post hoc fallacy and the non sequitur fallacy?

The post hoc fallacy and the non sequitur fallacy are sometimes conflated, but they are fundamentally different.

  • Non sequitur is Latin for “does not follow.” A non sequitur is an invalid deductive argument whose conclusion doesn’t follow logically from its premises because of its faulty structure. Any formal fallacy that doesn’t fall into another, more specific category can be called a non sequitur fallacy.
  • Post hoc ergo propter hoc is Latin for “after this, therefore because of this” and refers to an informal fallacy in which causation is assumed based on the chronological order of events. It is also called “post hoc fallacy.”