Trying to figure out what advice to follow in fitness is tricky. Conflicting opinions abound. And attempting to weigh them against one another is an infinite effort. So don’t. Find the argument. Forget the opinion.
This is a really sticky area for all of us. I see people make this mistake on both sides of a debate on just about anything. And your intellect and education does not shield you from this mistake. Part of the problem is that even really good experts forget that opinion is not argument. An argument stands alone. And it must be taken on its own terms. Opinion can be weighed based on the expertise and motivations of the one saying it. Argument does not rely on anything but it’s own soundness and validity (which I covered yesterday).
To help illustrate, imagine the following:
The Director of NASA with 40 years of experience in the field and numerous peer-reviewed published papers says, “based on my experience, I must conclude the earth is flat.”
Your crazy neighbor with an IQ of 80 and history of mental illness says, “if a model’s explanations and predictions are confirmed by repeated and independent observation, it is practical and provisionally true - the spherical model of the earth and Copernican principle make explanations and predictions which are confirmed by repeated and independent observation; therefore, they are practical and provisionally true.”
The expertise of the first and his motivations play into how we should weigh his opinion. He did not present an argument. There is an implied one we often insert, something along the lines of “if one person’s expertise is high enough, his conclusions are true; my expertise is high enough, therefore, my conclusion is true - and here it is!” This is a question-begging fallacy, of course, and an extremely common one. The implied argument is valid, but unsound. We mistakenly take that implied validity to equate with truth. But the premises are both question-begging and so obviously untrue. There is no level of expertise anyone can achieve which puts her opinions beyond question. Regardless, the expert did not present us with an argument.
In the second example, we have an argument. The person presenting the argument is immaterial to the force of the argument. Its logic is valid. That’s beyond question. If we accept the premises, it is sound. We could disagree over any one part of the premises, and revise until we find a commonly-agreed-upon wording. At that point, all who agree on the premises will end with the same conclusion. And it has absolutely nothing to do with the expertise or field-specific experience of the presenter.
We always hope that field-specific experience will help experts to present better arguments, but there is no guarantee. They could just as easily present increasingly strong-worded opinions, confusing themselves and listeners.
Look for arguments, not opinions. Evaluate arguments on their own terms.