I saw the film "Lucy" in 2015. The film says that humans can use 100% percent of the capacity of their brains.
According to my personal ideas, the capacity of the brain will changed based on the basic knowledge of a person. We all know Albert Einstein was a great knowledgeable human in the world. This level of knowledge can change by the time, for example he was arguably the best scientist or philosopher of his time; he used his brain as much as possible for innovation.
At the present, there are many more scientists in the world, but the world is filled with knowledge, new technology etc. Man's basic knowledge could be higher than a scientist in the past, because this knowledge is openly available everywhere. But the problem is that they don't use their brain to the same level as Einstein or any other scientist that has lived in the past. That means that they don't use the highest capacity of the brain.
So according to my idea, the capacity of the brain will vary depending on external environmental factors.
According to comments and suggestions in this article I read, I was unable to identify the truth: whether people can enhance their brain capacity like "Lucy". And I need to know whether humans have a fixed brain capacity or not.
Most religions say that their saints had used 100% of their brain capacity. So what about other humans?