I presume that you mean that you can't determine a prior cause. It's not something I've considered whether it is theoretically impossible to know all determinant causes. But that there are causes for the every event is a given. It's even the basis for the cosmological argument.
The Free Will -Determinism threads abound and it always comes down to these two positions
I am going to try to present the two sides as I seen these two positions stated.
Usual Valid Arguments:
1) Free Will There is too narrow a field for the person to be an agent (umbrella)
2) Determined However if the murderers of ZaZa are caused, therefore Fate, no agent
The scope of the OP is that all events have a priori but determining the path is indicating cause.
Refutation of Usual Argument #2 Determined
2) The future has a past but the past does not determine the future, then it is not determined.
It is merely one thing follows another. There isn't any cause to wash or not wash the dishes, instead watching TV.
Not doing the dishes did not cause me to watch TV. I just happened to wander by the TV and sat down.
You see? It was a chain of events but it was not determined by causes.
So no, a sequence is not determined unless caused.
Refutation of Usual Argument #1 Free Will
1) The agent decided to do the dishes. However, the phone rang and then the program came on the TV and so much for free will.
Again the question, is there an effective agent in that sequence?
Conclusion:
1) It is not determined, merely sequential
2) It is not free will because the agent lacks agency
Meanwhile:
Me and the cat are whimsicals in a wandering gravitational space/time warp.
As the spirit moves, we follow along.