Starting from a molecule on up, to cells and beyond, at what system level is a being actually making a decision rather than reacting to their chemical environment based on purely chemical laws? For example, the molecules in a cells are solely reacting to their environment based on chemical fundamentals. However, a person thinks things through and makes decisions. Where in that range do we see decisions start to emerge?
Frankly, the decisions that we make are chemical reactions. The difference is in the complexity of the decisions that we can make. At that point, though, in order to answer your question, we would need to argue about what one would consider to be a decision that’s complex enough and a decision that’s not complex enough, and that leans much more into philosophy and ethics rather than science.
I can only tell you that, from a mechanistic point of view, there’s not really much distinguishing our decision making process from, say, the decision making of a flatworm