I usually operate under the assumption that I (or anyone) could learn just about anything, but I think that there are natural limitations for certain types of knowledge, and whether they can be overcome is often up to the person.
An example that I’ll never forget is when I tried to teach my grandmother how to use a computer. She was probably about 80 at the time (she’s 94 now). I consider her pretty intelligent, but she couldn’t grasp the concept of using a mouse. Her hand was on the mouse, and I placed my hand on hers. I used my other hand to point to the screen where the pointer was and moved both my hands in conjunction so that she could see the connection between mouse and screen. When I let go for her to try on her own, she kept “spinning” the mouse, as if she were screwing a top on a jar. For a time, I thought it was simply an inconceivable concept for her, but maybe her desire to learn just wasn’t strong enough.
I would like to have the intelligence to adapt to the changes that I can’t foresee. To solve problems that I can’t think of. Kind of a non-answer, I know, but I want to be able to grasp concepts that are foreign to me, like the mouse was a foreign concept to my grandmother. She has yet to use a computer.