I think that one of the things that makes this notion of autonomy potentially incoherent is its apparent incompatibility with mechanism. Because if mechanism is true, there is no self-creating agency in the world. If there are agents at all, they are constituted in the way that anything else in nature is constituted.
Intentional explanations appeal to beliefs.
His belief that the gun was loaded caused his heart attack. His obsessive desire for revenge caused his ulcers. His htought his narrow escape from the rattler made him shudder. His obsessive desire for revenge led him to follow Jones all the way to Burma. He refused to pick up the snake because at the moment he thought of his narrow escape from the rattler.