If P is true then Q is true
Q is true
Therefore, P becomes more plausible.
But Annoyance was talking about logic, not plausible reasoning or probability theory, right? In terms of Aristotelian deductive logic the two errors quoted are pretty much equivalent.
In the words of a well known amateur pianist:
But Annoyance was talking about logic, not plausible reasoning or probability theory, right? In terms of Aristotelian deductive logic the two errors quoted are pretty much equivalent.
The statement “If P, then Q. Q. P is not ruled out.” is correct logic. But it conveys very little information.
How much information is conveyed, the amount we need to update our prior for P, upon learning Q, may be considerable. It depends on p(Q|P) and p(Q|~P)