This notion of free will where we have "the notional capacity or ability to choose between different possible courses of action unimpeded" and determinism "the view that all events in the universe, including human decisions and actions, are causally inevitable" is a topic of great philosophical debate and discussion.
Firstly, an all encompassing definition of terms may be difficult due to the debatable nature of consciousness itself. Great strides have been made since the early 20th century within the realms of quantum theory, which gives a reliable description of the nature and behaviour of matter and energy on the atomic and subatomic levels. It describes causation as a set of probability distributions where outcomes are not fixed until waveform collapse occurs. So as free will is a function of both time (the possibility for change) and consciousness, operating within this reliable description of quantum theory, one could say that the existence of free will is correct.
Are there degrees of freedom though, an interplay between deterministic and non-deterministic qualities to reality? I would say that this approach has merit due to the changing nature of the probability distributions themselves. How likely is the outcome of an event, and does this event include a conscious observer or not? As our knowledge of quantum theory and consciousness improves our understanding of the relationship between free will and determinism will improve over time.
