Post Hoc Ergo Propter Hoc

Hello!

Due to all the political ‘hoopla’ going on in the great state of Queensland at this time, because of the upcoming election in a few days time, I have been hearing a lot of political arguing. I have been pretty happy with the quality and the logic behind the arguments, but the Labor party (who is almost guaranteed to lose to the LNP this year) has been resorting to Post Hoc arguments and Ad hominem  attacks in the up-hill battle to hold on to seats. Today I will not be blogging about these arguments, but I think now would be a good time to introduce you all to these two logical fallacies. Today’s blog will be about Post Hoc Ergo Proper Hoc.

Post Hoc Ergo Proper Hoc is a common logical fallacy which often seems to hold weight at first sight and also seems logical in basis, but is not. Post Hoc Ergo Propter Hoc is latin for ‘after this, therefore because of this.’ You will see this argument everywhere, all the time, and for simple things, is logically valid. For example, to say that putting one’s hand on the hot stove will burn one’s hand. That is correct logic, but this argument breaks down when you try to apply it to even slightest of complex problems.

The most common use of this argument is in testimonials for alternative medicines and day-time television commercials for acne removal cream or the ab-circle pro. It is a perfect demonstration of this argument, and its flaws. If one has a sore back, and decides to go to the Chiropractor to fix it. The Chiropractor gives the patient some herbal remedies and a nice massage and manipulates his neck, and a few weeks later, the patients back feels much better. He tells all his friends about how the Chiropractor fixed his back, and all his friends go to the Chiropractor to get their sore back fixed.

This attribution to the Chiropractor is very illogical. There are a whole plethora of reasons why the patients back could have got better, other than the Chiropractor. The patients back may have gotten better any way, because it is a very arbitrary and subjective thing, back pain. He could have been the beneficiary of some pain-killers, or he might have been doing some home treatment like hot-packs and stretches, and that may have fixed up his back. It is unfair for the Chiropractor to get the credit.

It also is a common proof for some people that prayer works. If you pray for your friend Steve to make a speedy recovery from his Influenza, and he does recover, then you may attribute that to the fact that you prayed for it. Never mind the fact that everybody gets over the flu eventually.

I will leave you with a quote from an unknown author, “Correlation does not equal causation.” Anonymous, a Joe Klein, a 13th century English student and a New York Quartet group of some note.

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