"Unless you adopt the (almost certainly nonsensical) position that everybody is entirely born, not made, you have to concede some degree of environmental influence on people's eventual properties(the degree of that influence is certainly a matter of debate; but almost certainly isn't zero)."

That is not a nonsensical position. Once you are born, your DNA does not change.

If you were not born a deep thinker, you will never naturally be a deep thinker, regardless of how much training or practice you have. You may be able to become good at deep thinking, possibly through practice or training, but you will never naturally be a deep thinker, since you were not born that way. That applies to everything in life. You are entirely born.

As for a person's ability to be able to use their personal abilities and skills to their fullest can be environmental and can be influenced by a number of factors including personal circumstances and upbringing. But again, a person who is born to take advantage of their situation will find a way to maximize their life and those who are not born that way will not, given identical circumstances.

While you make some good points, your arguments are inherently incorrect based upon your misunderstanding of creative problem solving. Here is a link http://en.wikipedia.org/wiki/Creative_problem_solving. Note the second sentence in the second paragraph. Problem solving as a whole is considered the most complex of all intellectual functions. Mathematical problem solving is considered one of the highest, if not the highest, forms of creative problem solving. Also consider for a moment that effectively the entire field of computer science was originally developed by Mathematicians.

I would argue that writing code is a purely analytical process. I would also argue that people who believe programming is purely an art form or is best suited for people who are not analytical, for example musicians, make terrible programmers. From my personal experiences, these kinds of people are at best "hacks" and tend to write average or below average code, which may or may not work. And that same code is almost always poorly designed, poorly architected, poorly implemented, poorly documented and poor performing. All of the people whom I've worked with who are Mathematicians, Engineers, Physicists, etc. who are also professional software engineers tend to write exceptionally good code. They also tend to have the appropriate analytical and creative problem solving skills necessary to provide appropriate solutions to extremely complex problems throughout all levels of development from architecture to implementation.

Getting back to the Wikipedia article, your misunderstanding is based upon the fact that while musicians may be creative, that does not mean they are creative problem solvers. Creative problem solvers though can be purely creative. Which correlates perfectly with my own personal experiences, since most highly analytical creative problem solvers I know also enjoy pursuing such subjects as art, design, music, etc. As a matter of fact, most of the people I work with enjoy photography outside of work, not music. And the opposite is true, people who are only musicians tend to be neither highly analytical nor decent problem solvers.

I don't consider myself an expert and will never claim to be (on Slashdot or on my resumes). Claiming to be "knowledgeable and intelligent" is (to me) arrogance. As I've stated, it is a matter of degree and perspective.

Claiming to be knowledgeable and intelligent is arrogant? What are you talking about?

Here are some definitions for you:
Knowledge
Knowledgable
Intelligent

which has nothing to do with

Arrogance

Reading your entire post, it is clear you are insecure and trying to project your own inadequacies onto others.

Your current +4 Insightful rating is highly inaccurate.