Humans only use 10% (or less) of their brain's mental capacity

This is what i believe will be a very entertaining debate.
First round: case
Second round: rebuttals
Third round, conclusion (May not bring up new points) try to sway voters to vote for you
Good luck

Definitions
Evolution: a theory that the various types of animals and plants have their origin in other preexisting types and that the distinguishable differences are due to modifications in successive generations; also : the process described by this theory

The myth that humans only use 10% of their mental capacity is a blatant lie. I will refute this with the following points
P1: There is no purpose whatsoever to not use all mental capacity
P2: The only reason this myth is spread is because of people's shortcomings
P3: There is sufficient evidence to disprove this myth

Point one: Given that evolution is true, and that mutations to a species are for the benefit of the species, there is no logical purpose as to why the human would use only 10 % of their mental capacity. Considering that the brain supposedly has ten times the mental capacity that it uses, this puts man on a serious crutch because he is not aptly fit for survival. Not only that, but man would be inflicting his lack of intelligence upon himself.

Point two:According to neurologist Barry Gordon, "Though an alluring idea, the '10 percent myth' is so wrong it is almost laughable,"
The myth's durability, Gordon says, stems from people's conceptions about their own brains: they see their own shortcomings as evidence of the existence of untapped gray matter. This is a false assumption.
Gordon also says, "Let's put it this way: the brain represents three percent of the body's weight and uses 20 percent of the body's energy."
(My words following) If at a mere ten percent of mental capacity, the brain uses twenty percent of energy, than the brain must be very inefficient; whereas if it uses one hundred percent of its capacity for twenty percent of energy, it is very efficient.
as you can see, the brain uses one hundred capacity, there is no other explanation.

Point Three: These are but few of the reasons that the brain using to percent of the brain are debunked:
Brain imaging: Technologies such as Positron Emission Tomography (PET) and functional magnetic resonance imaging (fMRI) allow the activity of the living brain to be monitored. They reveal that even during sleep, all parts of the brain show some level of activity. Only in the case of serious damage does a brain have "silent" areas.
Localization of function: Rather than acting as a single mass, the brain has distinct regions for different kinds of information processing. Decades of research have gone into mapping functions onto areas of the brain, and no function-less areas have been found.
Microstructural analysis: In the single-unit recording technique, researchers insert a tiny electrode into the brain to monitor the activity of a single cell. If 90% of cells were unused, then this technique would have revealed that.
Neural disease: Brain cells that are not used have a tendency to degenerate. Hence if 90% of the brain were inactive, autopsy of adult brains would reveal large-scale degeneration.There have been countless tests, and all show the same results. The brain uses more than ten percent of its mental capacity.
http://en.wikipedia.org...
http://www.scientificamerican.com...
http://en.wikipedia.org...

Im con

Better yet, don't vote.
i don't want to accept a win because of a complication
please leave as a draw