There’s a scene in The West Wing– in one of the early episodes- when everyone is sitting in the oval office. The Ryder Cup team has just declined an invitation to the White House and Press Secretary CJ Craig relates the issue with their loss in Texas because of a joke the President made.
President Bartlet: “CJ, on your tombstone it’s gonna read, ‘Post Hoc Ergo Propter Hoc’”.
CJ: “Okay, but none of my visitors are going to be able to understand my tombstone.”
President Bartlet: “27 lawyers in the room, does anybody know post hoc ergo propter hoc?”
Josh Lyman makes an attempt to translate but fails. Leo comes up and tells the room it means “after, therefore because of.”
President Bartlet: “It means one thing follows the other, therefore it was caused by the other, but it’s not always true – in fact it’s hardly ever true. We did not lose Texas because of the hat joke.”
Post hoc ergo propter hoc is one example of a logical fallacy. It’s something you’ll see everywhere once you know what to look for. If a person has a minor back tweak after a deadlift and goes to the Doctor, an MRI may reveal a slight bulge in a disc. Since this happened after deadlifting it seems to be what caused it. However, it’s entirely possible the bulge was there before deadlifting but never caused a problem. The doctor may not know this and conclude that since the bulging disc followed the deadlifts, they caused it, and therefore deadlifts should be avoided.
Ad hominen is another fallacy where the person making the argument is criticized rather than the argument itself. It’s when you try and suggest someone try overhead presses to get their upper body stronger and they say it’s a silly exercise because you’re not that strong. That may be true. But that doesn’t respond to the claim that presses could be a useful way to get stronger.
Lastly, an appeal to authority attempts to use only a person’s “expertise” or status rather than evidence. When someone makes a claim it should be examined on its own merit, not blindly followed. A physical therapist may tell you that squats are bad for your knees. But if they can’t support the claim with more than “Trust me, I’m a professional,” then you’ve got a problem.
