I feel my opinion on IQ is superior.
A little background, I'm a very gifted person but also had a childhood of malnourishment, poor food choices, drugs and alcohol, and leaving school ay the age of 14. My IQ should be low, the vast majority of people with my upbringing are below 80 IQ. I was born extremely gifted. 150 IQ. It hasn't diminished with the use of drugs at all. It has certainly increased since childhood, I'm the greatest I've ever been at everything.
The key truly is rigorous thought.To
a degree it's true that nobody is stupid. With a physical therapist, a person can learn to use muscles that hadn't activated in an athletic movement before. This is coordination. People have uncoordinated brains. You can increase this coordination by a fuckhuge degree, perhaps without limit because you have quite a large variety of neuro pathways to bridge.
tl;dr you're born with your mind but just like a body it must be maintained, some things can destroy a brain while for another person those same things can empower a brain and this is simply due to the patterns of our lives.