Aristotelian “Weakness of Will”


It is sometimes said that Aristotle’s answer to weakness of will is building good habits. Socrates said that to know the good is to do the good. Aristotle objected that people might fail to do the good simply out of weakness of will (laziness, cowardice, etc.). Building good habits, says Aristotle is the key to overcoming weakness of will.  But I wonder if building good habits really is a prescription that works.
Imagine a couch potato who doesn’t have a very strong will. Suppose the couch potato knows that he ought to get off the couch and that its in his best interest to do so. Presumably, Aristotle would advise such a person to start building good habits in order to overcome the problem. He might start by getting up early, turning off the television, creating a schedule and working with a day planner, etc. He might even get off the couch and exercise in his living room. Over time, these habits would become more and more a part of his routine and over time he would become more productive.
But there is what Quine would call “an air of circularity” about this: doesn’t he need more strength of will to start a day planner and exercise and get up early in the first place? If the problem was weakness of will to begin with, won’t that become an obstacle to developing good habits? In short, Aristotle seems to be assuming the the solution to the problem lies in the premises that were introduced to solve it.
How then do you deal with weakness of will itself? Is there any one prescription that actually would work as the core to any w.o.w. problem? We could try pressing further with Aristotle’s solution: perhaps one could engage in will-building exercises. Perhaps one could chart one’s progress in incremental steps. Something tells me this wouldn’t get very far with an entrenched couch potato. But is Aristotle nevertheless right?