Explanation

Your first clue is “free will.” One can only be responsible for the things one decides, or freely wills, to do. For the second blank, the word instead, even though it occurs later in the sentence, implies that Dr. Wegner is avoiding the traditional talking points of the controversy, or eschewing them.

The word though indicates that the third blank contrasts with the word tangential. Fundamental is thus the most appropriate answer.

Responsible for, eschews, fundamental.
_________________

am still a bit confused as to how to pick between "responsible for" and "aware of."
Couldn't we say that free will is related to being aware of your actions?

Below was how approached the question - including the choice between the two options:

First tackled blanks (ii) and (iii) - do let me know if that is not clear.
Debates over free will have always focused on the extent to which humans may be said to be fully (i) _________ their actions.Dr. Wegner in his article deliberately and artfully eschewed the traditional talking points of the controversy, instead asking a tangential, though possibly more fundamental, question: What effect does a person’s belief in free will have on his or her well-being?

So what do we get from the context:
"Free will" is a controversial topic, and whenever this is discussed a particular point a always at the center of it. This is something which was cleverly omitted from one of the scholarly articles - probably knowing the controversial nature etc.

What is the result of "will" / "free will" ? => actions;
What could be good/bad/controversial ? => outcome/impact of these actions
Hence we are looking for a word that assigns some form of accountability for these actions/outcomes (which is the topic of controversy in the discussion of "free will")

When I look at the options:
"aware" - seems like a neutral word, it doesnt ring of accountability we are looking for, it lacks "strength" that we are looking enough to make a controversy.=> but I will keep it, unless I find a better word
"responsibility" - seems apt and has the characteristics we are looking for. (a much better choice than "aware")

"aware" would be my second best choice within the options.

Hello from the GRE Prep Club VerbalBot!

Thanks to another GRE Prep Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.