I think that the “could” idea does not need to be confined to the process of planning future actions.
Suppose we think of the universe as a large state transition matrix, with some states being defined as intervals because of our imperfect knowledge of them. Then, any state in the interval is a “possible state” in the sense that it is consistent with our knowledge of the world, but we have no way to verify that this is in fact the actual state.
Now something that “could” happen corresponds to a state that is reachable from any of the “possible states” using the state transition matrix (in the linear systems sense of reachable). This applies to the world outside (“A meteor could hit me at any moment”) or to my internal state (“I could jump off a cliff”) in the sense that given my imperfect knowledge of my own state and other factors, the jump-off-a-cliff state is reachable from this fuzzy cloud of states.
I think that the “could” idea does not need to be confined to the process of planning future actions.
Suppose we think of the universe as a large state transition matrix, with some states being defined as intervals because of our imperfect knowledge of them. Then, any state in the interval is a “possible state” in the sense that it is consistent with our knowledge of the world, but we have no way to verify that this is in fact the actual state.
Now something that “could” happen corresponds to a state that is reachable from any of the “possible states” using the state transition matrix (in the linear systems sense of reachable). This applies to the world outside (“A meteor could hit me at any moment”) or to my internal state (“I could jump off a cliff”) in the sense that given my imperfect knowledge of my own state and other factors, the jump-off-a-cliff state is reachable from this fuzzy cloud of states.