The question is not whether or not there is choice, but whether or not their is choice free of external causes. The definition of freewill is "the power of making free choices unconstrained by external agencies."
To answer the question I need more precision for what "free of external causes" means as well as "unconstrained by external agencies." They seem to be trying to say the same thing but in my mind will lead to two very different answers. [...] we can interpret "unconstrained [by external agencies]" more rigidly. We have physical limitations, many would argue psychological limitations (which I think is the more interesting debate...do we have psychological limitations?), etc. By this interpretation of the word, there would be no free will.
I agree, this need for definition is the crux of the matter. And I would argue that there
is free will.
Humans are endowed with meta-consciousness, which negates any argument that sociological or any other kind of "mental conditioning" is a limitation on free will. The very fact that we are able to see those limitations frees us from them. Obviously this is a broad generalization - not everyone is going to come to the realization that "I think X because I was taught Y, and I don't necessarily have to react the way I was taught." However, the question was "is there free will," not "does everyone have free will," and that is the question I am addressing. Although I would go so far as to say everyone has the
possibility of free will, if they're willing to work (and in many cases, sacrifice deeply held beliefs) for it.
What is left, then, is whether or not we would define the
physical process of thought as an "external agency" that constrains us. If the limitations of the firing of neurons in our brains
are our definition of our limits of "free will," then perhaps we are limited. But that would imply that there is some kind of "free will" that exists beyond the physical capacity of our brains. Which begs the question: is it possible to "think" in a way that transcends our physical capabilities of thought? What, then, becomes of the definitions of "thought" and "consciousness" themselves?
Keep in mind that the concepts of "will" and "free will" were brought about within those same physical limitations. That is to say, the idea of "free will" itself, as a concept, exists only within the context of "thought" - the firing of neurons in the human brain.
Therefore, also within that context, I think free will
must exist - because humans have the capacity to reach the physical limits of the brain (perhaps beyond), overriding any ingrained, learned patterns.