Final answer:
David Hume's philosophy identifies the controversy surrounding free will as the conflict between deterministic causality and the human experience of moral responsibility and choice.
Step-by-step explanation:
According to David Hume, the source of the controversy surrounding free will lies in the tension between determinism and the feeling of moral responsibility. Hume suggests that our actions appear to be a result of the laws of nature, much like the falling of a book subjected to gravity, thereby supporting a deterministic view. However, we also experience a sense of choice and moral responsibility that implies some form of freedom. The controversy, therefore, arises from the attempt to reconcile determinism with our experience and capacity for choice. In summary, the dilemma can be characterized by the interplay between causality, moral responsibility, and the empirical basis of knowledge, which is central to Hume's philosophy.