When trying to spot the charlatan in health and fitness or any other walk of life, it's good to be armed with a well trained skeptical ear. One of the things you should be listening out for as a skeptic is the use of unsound reasoning when someone is defending, promoting or selling an idea, position or product. Don't worry you don't need a degree in philosophy to understand this stuff, just a grasp of a few simple ideas and principles.
The first thing to understand is what an argument is. When someone is making a claim or selling something they will on some level make an argument for what they are claiming or selling. The argument will consist of one or more premises and a conclusion.
The premise is either true or false and supports the claim being made (the conclusion) which is itself either true or false.
So for example, someone promoting an exercise programme might say "by doing x, y or z you will gain fitness faster". The premise is doing x, y or z and the conclusion is; you will get fitter faster.
A logical fallacy is an error in reasoning in which the premises don't provide an appropriate level of support for the conclusion. So to use the example above, if the reasoning behind doing x, y or z to get fit fast is unfounded then the conclusion that you will get fit fast cannot be seen as necessarily true. One thing that It is important to note about fallacies is we are not talking about getting the facts wrong about something in the premise. We are talking about fallacious reasoning not factual errors.
There are loads of different logical fallacies that have been defined and named and spotting them can be tricky but after a while you can pick up on them quite quickly. The only issue I find is remembering which one has been committed!
Here're a few well used logical fallacies to get you started with examples of where I've heard them being used:
1: Post Hoc Ergo Propter Hoc which is Latin for 'After therefore because of'
This is a classic in the fitness industry where claiming that because B happens after A then A must have caused B. This is not necessarily the case and is therefore a fallacy.
Have you ever heard someone at the gym say that after taking this or that supplement they put on muscle or perhaps you've heard someone say that their back pain got better after they started doing a particular stretch.
If these people are saying that the particular things they are talking about lead to the outcome, they're committing the Post Hoc Ergo Propter Hoc fallacy. In the first example the person can't attribute any muscle gain to a supplement without specific scientific investigation . Who's to say that the training programme isn't the reason and they would've gained muscle without the supplement or some combination of things lead to the effect. In the second example how does the person know that their back wouldn't have got better without doing the stretch or that something else they're doing in their training is the main reason for the pain going.
2: Argumentum ad populum or the appeal to popularity.
Another classic in health and fitness where something is argued to be valid purely because a lot of people do it or believe in it.
I was talking to someone recently who was a big Crossfit fan. (Crossfit joke: How do you know if someone does Crossfit? Don't worry, they'll tell you!)
Anyway; this person told me that Crossfit was by far the best form of training. When I asked how he knew this he said "well so many people do it and they all get really fit" !!?
Now there maybe some good arguments about why Crossfit is a really good form of training but saying it is so because a lot of people do it is not one of them!
Somewhere else you'll hear this fallacy a lot is in the world of diets. To put it simply, the position of a diet book in the best sellers list does not speak to the efficacy of the diet. I've lost count of the number of times over the years that I've heard someone say this or that diet is great using it's book chart position as support for the argument. (Mr Atkins, I'm looking at you!)
3: No True Scotsman:
This fallacy is committed when someone defines a group as having specific qualities then re-defines the group if a counter example is presented. The name derives from an example that states "All Scotsman eat porridge" "but what about so and so, he's Scottish and doesn't eat porridge?" "Ah but he's not a true Scotsman"
Again to use an example from my own experience. While I was working as the Fitness Manager at a health club in Notting Hill I was having a conversation with a yoga teacher. During our discussion she told me that yoga was brilliant and implied that everyone who did yoga was relaxed, chilled and spiritual. When I told her that I regularly had run in's with irate yoga participants about various non issues and they didn't seem like that to me she just insisted that these people obviously weren't serious about yoga?! 'No true yogi' perhaps!
These are just a few of many logical fallacies that people often use when arguing their case. I'll address more in future posts but in the mean time turn on your skeptical ear and see if you can spot some erroneous reasoning for yourself.