Using 100% of the Brain

From Ilchi Lee’s book BEST 5 Handbook

When I speak of using 100% of the brain, I am not talking about using all the physical parts of the brain. I am talking about accessing 100% of its full potential. I would contend that although most people are using all the parts of their brains, very few are using 100% of its full potential. I believe your brain’s abilities may exceed your expectations.
Think of your brain as similar in some ways to a muscle in the body. If you lift a fifty pound weight with your right arm, there is no doubt that 100% of your bicep muscle will be used. All of the muscle fibers will be engaged in the task of keeping that weight in the air. But does this mean 100% of that muscle’s potential is being used? With training, the muscle may be able to lift 100 or 200 pounds, or perhaps even more.