What is determinism, but a fatalistic play in motion? What is causality?

Humans like to resolve causality down to one factor, even if it's only correlated. Causality is an abstraction. But is it understood through inductive reasoning or deductive? We tend to think as certain functions of our body happening autonomously, without a decision in our mind, but then we think of "choices" we ascribe that to a decision that's made regardless of some of the parts that influenced it. So, if we have so many aspects of our body that happen unconsciously, how can we say that our conscious decisions are anything but controlled by things outside our control?