The statement that “the self can cause the self” is necessarily false because of its self-referential nature (reductio ad absurdum). In other words, the Will cannot will itself to be something different from what it already is.
The above effectively “solves” the problem of “free will”, in the sense that it demonstrates the absurdity of a type of concept of “free will” that people commonly hold.
Having said that, the Will nonetheless exists with a reasonable degree of agency and autonomy which is (ironically) directly proportional to the degree that the world is deterministic. This is because, the higher the degree of determinism, the greater the capacity of the present self to causally determine the future self.
If my present self knows that obesity is unhealthy, my present self can then make intentional changes to my lifestyle so that my future self becomes healthier. Likewise, if I now know that I am ignorant, I will seek knowledge so to ensure that my future self is a wiser person. In this way, determinism is actually the answer we have been looking for.
However, if causality is limited, or even non-existent, then it means that the present self has no power to intentionally influence the future self. In that case, it becomes completely up to chance whether one becomes a better or worse person as time goes on. Without causality, we are completely screwed over by the universe.
This understanding of the interrelatedness between determinism and agency/autonomy has profound implications on our morality/ethics. Knowing that knowledge is what ultimately empowers people to make good decisions/choices for themselves, we have a moral obligation to support education, rational inquiry, etc., in the hope of improving the human condition.
The state of our present self gets to dictate the state of our future self, and therein lies the true autonomy/agency that we all have been searching for. (Of course, whether we like it or not, we cannot choose for our future selves not to be determined by our present selves.)