Our knowledge about the outside world is tentative and based on a series of assumptions.
In particular, it’s extremely difficult even to identify the operation of a free will distinct from the recognized determinism and/or ostensibly random phenomena, let alone to determine the nature of that free will.
With that said, the possibility of free will can’t be ruled out, because of our knowledge of tentative conclusions, ignorance, and of the diversity of sensations known and previously unknown, yet now known to us.
Because of that, we should proceed as though we might be able to optimize our value function, on the objective materialist basis.
There are different categories of predictable phenomena: roughly these are physical -> poorly understood or limited-applicability physical -> human behaviors.
Conventional attribution (giving intent to humans) can’t be relied upon as a prediction technique in many of the situations where we would demand it.