For the mind, at least insofar as i have plumed it. What exists for it are possibilities, with varying probabilities of certainty. These possibilities exist in a state of flux, their "solidity" for the mind, a measure of it's certainty, depend upon the information available to it. As such, the mind is merely a tool, just like the body is also a tool. That is why the mind & body are so strongly coupled together, they have an affinity for each other. In this view, mind & body cannot choose anything, as they are merely tools for the gathering, processing, & transmission of information.
That which can choose, is of a vastly different nature, quality, and configuration. It is what Gurdjieff called essence, osit, and what i would call spirit. Spirit/essence & emotion are strongly coupled together, the same way mind & body are. The mind & body have various mechanisms to translate the information communicated by spirit into thoughts, among other "things."
Since the ability to choose, which is free will, is greatly determined by the availability of information, and the proper usage of various tools to analyze, process, & utilize said information. The tools used for analysis cannot pick and choose a given course of action, any more than a computer can choose to surf the internet. The user of the mind & body is the only "thing" that can choose. The user=spirit=essence, osit.
The importance of knowing one's machine, is thusly reinforced, for the ability to discern between internal & external influences being translated, and thus perceived as self by the mind, depends upon the state of development of the observer. It is the observer in the mind, which is a result of efforts to observe oneself, and reality, that makes it possible to even begin to perceive the communications of spirit through emotion as intention, and thus be able to begin to exercise freewill osit. The observer is that which can pave the way for the seating of that which is, in the mind, it is nothing more but a "height" that has been attained through intentional suffering, and conscious efforts, that is why and how it can observe osit. Thus we can reconcile the Gurdjeffian view that humans are machines, with the Cassiopaean view of organic portals and souled humans.