The core of the flaw in your proposition is the premise of making the determination based on external observation.
The actual question is this: do I have free will or not? Life presents us with choices. To paraphrase the prince of Denmark, 'Do I decide to do x or !x? That is the question'.
Related question is does I (distinct from Reality) even have a real existence?
In the 2 slit experiment, as long as the future state of the system is undecidable, we see light behave as waves. When the future of the system is constrained (by measure, which is a 'means of determination') does light behave like a particle.