Can Do and Can Try

As has been previously discussed, in On the Freedom of the Will, Schopenhauer asserts that 'I can do X' links 'I will X' to 'I do X'.  However, closer examination discerns a crucial lacuna over which his analysis glosses.  For, 'I can do X' means, more precisely, 'On the basis of my past experience, I feel confident that if I attempt to do X, then the attempt will be successful.'  In other words, while it might always be in one's power to attempt some action, its success is never guaranteed.  So the referent of  'I can do what I will', contrary to Schopenhauer's thesis, does not suffice to connect a volition with the actualization.of its object.