In the life sciences, statistical analysis is used, because their theories have not fully reached causal determinism. Instead of cause and affect; accurately predict the future of evolution, for example, things are based on odds, which like buying a lottery ticket and winning, is not a sure thing. Probability leaves things open ended, albeit with some things having higher probability. However, nothing is assigned 100% certainty, which is a rule of probability. How can you have determinism and probability at the same time? Will power offers choices, that can defy the odds, in a theoretical land where there is no sure thing.
Nobody has been able to form life, in the lab, from scratch; Abiogenesis. If this was based on determinism, why is everyone unable to find that determinism? This is not to say that that determinism does not exist, but rather the ego, can't find it, even if it is determined to try. Instead science, diverges in many directions, none of which are fully predicted; deterministic. The only thing that is deterministic here, is the lack of determinism.
In the Bible, there were two trees; Good and Evil, and Life. Life is about natural instinct or the natural integration of life both internally and externally. Good and Evil is not as integrated, but is more relative. This symbolic tree of good and evil is where free will appears. For example, transgender to the extreme Left is called good, while to the extreme right it is called evil. Knowledge of good and evil is often relative and subjective, not always predetermine by one set of logic. Subjectivity, adds wild cards, allowing the determinism of natural instinct to become blurred for subjective will and choice.
We have two centers of consciousness; inner self and ego. The inner self is natural and is the center of the animal brain. All animals have an inner self. The ego is much newer; 10K years old, and is only found in humans. Although the higher domestic animals, like a dog, can form a virtual ego; trained to become unnatural; neurotic, to serve the needs of the owner's ego. One may need a professional trainer to reverse and/or shut off that virtual ego, so the dog's inner self can come to the front. When domestic dogs go feral, their inner self is restored, however, the option of a virtual ego remains; new owner can induce it to coordinate with instinct; natural, or run contrary to instinct; neurotic.
When you have two centers, where each center see the world by two different systems; how the same data is processed, the two systems do not have to coordinate. The Tree of Life, and Tree of knowledge of good and evil, caused a parting of the ways; ego and inner self. This is the original mention of free will and choice; connected to the appearance of the ego. The human ego may have begun as a virtual ego, complementary to the inner self. But as time went on, it finally stuck and became self standing, allowing will and choice to appear.
The way this works, in practical terms, is the ego is more differential; left brain processing, while the inner self is more integral; right brain processing. In calculus, there are two different math operations; differentiation and integration, that treat the same equations, differently. The ego differentiates reality, allowing it to see itself as a certain ethnicity or skin color. This makes anyone outside that set, seem different. The inner self integrates, and sees how all humans are part of the same species. These two different POV, make it hard to overlap 100%, leaving room for ego choice and will; subset. The inner self is more 3-D while the ego is 2-D or less.