The greatest hindrance to the discovery of evolution by natural selection was the illusion of design. That the existence of complexity implied there must have been a grand watch maker – a god.
Despite the fact that the evidence for evolution by natural selection is as strong as, say, the earth being round it is controversial outside of science, being a genuine problem for religion. The removal of directed action or free will, would face a similar challenge.
This teleological illusion extends to purpose as well as design. Yet there is no equivalent of the theory of natural selection which replaces the notion of purpose, or free-will (to give it its exalted use when describing the actions of human beings) when looking at very complex passive actions which somehow look actively driven.
The notion that life forms are autonomous agents is not restricted to spiritual ideas of a ghost in the machine, but is commonplace in life sciences vis a vis Stuart Kauffman who views living things as able to act on their own behalf.
On further examination, the idea of action on ones own behalf leads to reductio ad absurdum: