The statement of "we are using just 10% of our brain" is commonly portrayed as a stupid myth.
But much of those arguments are untrue, or at least very misleading.
Ok. If anyone was dumb enough to see the brain as a football field, and the 10% meaning that the mind is dribbling in the last 10 yard, then yes this is stupid and definitely untrue.
The common meaning of the 10% is that we use a small part of our potential. Which is definitely true.
Most of us can learn endless skills, and might be able to mange life vastly better. The exact extent to which this is practical and doable is a huge unknown. But we can all learn to dive, play football, type blindly, and some music . We do not. But there is definitely potential.
What can we learn from this "skeptics" debacle?
1) It is very hard to debunk something without at least trying to think what it means, and pretend for a minute that you beleive it. Otherwise, you debunk something else....
2) Mixing absence of evidence and evidence of absence. There is definitely no precise evidence that we use 10% of our brain potential. But this is very far from a proof that this is not true.
3) Measurement addiction is risky. When failed debunkers attacked the 10% idea, they imagined the meaning is literal as the 10% implies. But this is an error. 10% used is not about measurable space used or blood flowing in the brain. In fact, we might use *more* of our brain when we do not think (the so called "default network" in the brain is a quite active beast).
4) Not everything can be proven vs disproved. Some ideas are just not lying down to your preffered procrustean bed to be handled. Which is fine. Of course something that has not shown clear evidence or which cannot be tested easily is not a proven fact. But it is neither a "myth" to be "disproved" with illogical arguments.