I stand here in front of you today all because of an idea
I could be who I wanted if I could see my potential
Macklemore says here that he needed to realize that he had potential before he was able to do what he wanted. This was the idea that allowed him to stand where he is now. (Number 1 on iTunes as an independent artist)
If not a direct reference to the Human Potential Movement, this line certainly expresses a closely related idea.
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