Does It Count As Voluntary If The Bus Driver Was Drunk?

More on Anarchy, State, And Utopia, this time in regards to discussion of marriage and voluntary exchange. Nozick proposes the following rule for determing whether a person's actions are voluntary:

Whether a person's actions are voluntary depends on what it is that limits his alternatives. If facts of nature do so, the actions are voluntary. (I may voluntarily walk to someplace I would prefer to fly to unaided.) Other people's actions place limits on one's available opportunities. Whether this makes one's resulting action non-voluntary depends upon whether these others had the right to act as they did. (p. 262)

Which seems way, way off to me; either he's decided to offer his own, idiosyncratic definition of "voluntary" or he's just completely missed the boat on this one. It seems to me that the question of whether an act is voluntary (or coerced) turns not on how one arrived at a particular choice but rather on the set of anticipated outcomes the choice might generate.

Nozick illustrates his definition by way of a marriage scenario. Rather than writing out the entire passage, which is somewhat lengthy, I'll direct you to p. 263 in the book and summarize as follows:

• There are 26 men arranged in descending order of desirability from A to Z.
• There are 26 women (A' through Z') similarily arranged.
• A marries A' by mutual consent, leaving B to marry B', C to marry C', and so on.
• At the end of things Z and Z' are left with the choice to marry (or not). Nozick asserts that this decision is voluntary.

I agree that the decision is voluntary, but perhaps for different reasons than Nozick. Let's consider 2 counter examples:

• Example 1: Suppose that A through Y and A' through Y' all get on a bus to go sightseeing in the Swiss Alps. Unbeknownst to them the driver is roaring drunk and drives the lot of them off a very high cliff, killing everyone aboard. Z/Z' are left to marry or not as they see fit, a decision which would almost certainly be considered "voluntary" according to the common understanding of the word.
• Example 2: Same scenario as Example 1, but the driver of the bus is stone cold sober. Instead, an avalanche sweeps the bus off the road and over the aforementioned cliff. Z/Z' are faced with exactly the same range of choices as in Example 1, though this time their choices have been limited by a "fact of nature" rather than an illegitmate act (drunk driving).

The above illustrate why I think it's wrong to focus solely on the set of available alternatives when considering whether an act is voluntary or coerced; the anticipated outcomes of the decision are clearly relevant as well. I believe Examples 1 and 2 to be pretty much a slam-dunk; it seems absurd to think that the determination of whether Z/Z' are marrying voluntarily should turn on whether the other 25 couples were killed by an avalanche or a drunken driver. And what happens if Z/Z' don't know the exact cause of death? How can facts which they do not know be at all relevant to the question of whether they are acting of their own volition?

The fundamental flaw with Nozick's definition of voluntary action is that it's a path function; what matters is not the spectrum of possible outcomes, but only how one arrived at the choice. This seems to run counter to the whole concept of volition; choosing is an inherently forward looking process wherein you (as a rational actor) balance the anticipated costs and benefits of each available course of action and select the one which most appeals to you. How you arrive at a particular choice matters only to the extent that it shapes the anticipated outcomes available to you.

Of course, the real question is what constitutes "coercion" under this formulation? Consider Nozick's example of someone who must work at some menial task or face starvation. Does ey choose of eir own free will to take the job? And how does this differ from the situation where someone forces em to work at gunpoint? Those are tough questions for which I don't claim to have anything approaching a complete answer. My gut says that in both situations (starvation and gunpoint) the person so affected is acting with the same amount of volition (which we needn't specify); what differs are the external circumstances driving the person to that choice. So perhaps we should focus on these immediate (rather than historic) extrinsic factors and leave the concept of free will (if such a beast truly even exists) to someone else.