316 RELIGION, MORALITY, FAITH, AND REASONCausal impossibility: State of affairs A is causally impossible if and
only if A obtains only if some law of nature is false.
Compatibilists take it to be possible that a bit of behavior be in fact
inevitable and one that one is morally responsible for performing.
Compatibilists and incompatibilists typically agree that human beings
never perform actions that are logically inevitable or causally impossible.
Libertarians deny that human actions are typically in fact inevitable and
add that, were they, no one would ever be responsible for them.^13
Compatibilism and actions versus nonactions
The compatibilist thinks that whether determinism is true or not, and
hence even if it is true, we can have the sort of freedom required for moral
responsibility. Hence he holds that this sort of freedom regarding some
thought or action is compatible with that thought or action being in fact
inevitable.
One may be responsible for what one does, but also for what one does
not do. A friend who could easily have stopped your progress and knew
what would happen if he did not, but nonetheless allowed you to walk into
the path of a moving vehicle, is not innocent merely because she did not
push you into its path. For simplicity, however, focus here will be on
responsibility for what one does. Regarding such responsibility, Karen is
responsible for action A entails Karen performed A.
Let Karen’s states at time T refer to all of the physical states Karen’s
body is in at T and all of the mental states her mind is in at T. If
determinism is true, each of those states is in fact inevitable, given the
content of the past. Let us say that a causal chain passes through Karen at T
if and only if at least one of its members is also one of Karen’s states at T. If
some action by Karen is a member of a causal chain – a chain whose earlier
members result in Karen performing that action – let us call it an action
chain relative to Karen; for short, an action chain. Any action chain
relative to Karen must pass through Karen.
Consider the various sorts of mental states that one can be in that are
relevant to how one acts – intentions, purposes, goals, preferences, likes,
dislikes, desires, wants, choices, and so on. Let these be action-inclining states.
Action-inclining states relative to chewing a stick of gum will include desiring
to chew it, intending to chew it, having chewing it as a purpose or a goal, and
the like. If a chain passes through Karen but contains no action-inclining state
of Karen’s, then even if it results in some motions of her body, it is dubious
that it is an action chain regarding her. There is a difference between Karen’s