The Garden of forking paths

Libertarians generally define freedom of choice in terms of freedom of opportunity: the freedom to do otherwise. This is then cashed out in terms of possible worlds semantics: alternate possibilities. Here are a few standard definitions:

Many do not follow Fischer here, however, and maintain the traditional view that the sort of freedom required for moral responsibility does indeed require that the agent could have acted differently. As Aristotle put it, “…when the origin of the actions is in him, it is also up to him to do them or not to do them” (1985, Book III).[3]

Incompatibilists think that something stronger is required: for me to act with free will requires that there are a plurality of futures open to me consistent with the past (and laws of nature) being just as they were. I could have chosen differently even without some further, non-actual consideration's occurring to me and ‘tipping the scales of the balance’ in another direction. Indeed, from their point of view, the whole scale-of-weights analogy is wrongheaded: free agents are not mechanisms that respond invariably to specified ‘motive forces.’ They are capable of acting upon any of a plurality of motives making attractive more than one course of action. Ultimately, the agent must determine himself this way or that.

http://plato.stanford.edu/entries/freewill/

To have free will is to have what it takes to act freely. When an agent acts freely—when she exercises her free will—what she does is up to her. A plurality of alternatives is open to her, and she determines which she pursues. She is an ultimate source or origin of her action. So runs a familiar conception of free will.

Finally, the plurality conditions require that, whichever choice is made, there have been at least one alternative choice that the agent was able to make such that, had she made it, it too would have satisfied the previously stated conditions.

http://plato.stanford.edu/entries/incompatibilism-theories/

There are other versions of libertarian freewill, but since this is the basic version which is deployed against Calvinism, this is the version which I’m going to examine. Let’s play along with this version and see how far it will take us when we try to take it to its logical extreme.

1.Let’s say I want to buy an Alfa Romeo. So I stroll through the car lot, scoping out various models. I’ve narrowed my choices down to either the red Alfa Spider or the red Brera.

According to our operational definition, each choice represents a possible world-segment. There’s a possible world in which I buy the Alfa Spider, and another possible world in which I buy the Brera.

For that matter, there’s a possible world in which I buy both, as well as a possible world in which I buy neither.

2.But this, in turn, generates certain metaphysical entanglements. For the car is not a discrete object, existing in a physical or metaphysical vacuum. The car is of a piece with the car lot. And the dealership. And the salesmen. And other customers—in time and place.

The car lot is of a piece with the town, while the town is of a piece with the earth, and the universe. So, in choosing a car, I’m not just choosing a car. I’m choosing everything else that goes along with the car, metaphysically speaking. The past. The whole causal matrix.

I’m instantiating an alternate possibility in which a particular car is a part of a larger package of things. And I am bringing that well-furnished possibility into being by my particular choice.

3.This ascribes a remarkable degree of control to the free agent. The individual agent is responsible for instantiating big chunks of reality.

Not only that, but he has control over other free agents. By choosing the Brera, I instantiate the alternate possibility in which those salesmen exist. I bring them into being. I make them actual. They now exist in the world-segment I chose for them (by choosing the Brera), and they exist in that world-segment, rather than some other (as abstract possibilities), because I chose it.

If I buy the Brera, then they exist in the world where I buy the Brera, rather than the world where I buy the Alpha Spider. And if I bought the Alpha Spider instead…but you know the drill by now.

4.But how is it that one free agent has that much control over another free agent? Wouldn’t the entanglement of my choices with their choices work both ways?

How can my choice commandeer them into existence when they are making choices which likewise affect or even effect the world segment to which I belong?

Suppose a salesman buys a snack at the vending machine. While I deliberate between the Brera and the Alpha Spider, he deliberates between the popcorn and the candy bar.

So whose choice selects for the other agent’s choice? Does my choice of the Brera in turn select for a world-segment in which he chooses the popcorn? Does his choice of the candy bar in turn select for a world-segment in which I choose the Alpha Spider?

5.Since not all possibilities are compossible, wouldn’t all these metaphysical entanglements generate a state of metaphysical gridlock? How can I, by my choice, drag you kicking and screaming (as it were) into my possible world-segment when you, by your choice, are hauling me into your possible world-segment?

If each choice corresponds to an alternate possibility, and each choice is a subset of a larger, possible world-segment, then my choices are tangled up with your choices. Yet each choice represents a different possibility. And differing possibilities cannot be simultaneously realized.

6.It will hardly do to say that God is harmonizing and coordinating our respective choices, for—according to libertarianism—God either cannot or will not force us to agree. For that would be oh-so coercive, ya know. Hence, I must have the freedom to make choices which are incompatible with the choices you make.

7.Suppose two customers want the same car. There is only one red Brera on the lot, and both of us want to buy it. But we can’t both have it. So only one customer ends up buying the car.

But how is it that one customer is able to access the alternate possibility in which he buys the car at the expense of his rival? How can he prevent me from accessing the alternate possibility in which I buy the car?

Why do some free agents enjoy greater metaphysical access than others?

8.Or, to approach our scenario from a different angle, why do we even need to fight over the same car? After all, there is yet another a possible world in which the car lot has two red Breras for sale. Why am I stuck with the range of options I see in the car lot?

I hope the libertarian won’t try to tell me that the real world imposes certain limitations on my freedom of opportunity. For, if this version of libertarianism is true, then the real world is largely the sum-total of all those compossible world-segments which free agents individually realize.

That’s the whole point of libertarianism. The real world is not a fait accompli. The world is what we make it—literally!

So don’t turn around and tell me that the real world infringes on my freedom of choice when you are also telling me that free agents are creating the real world as they go along, moment by moment, by which possible-world segments they instantiate.

Logically, the only restriction on my choice would be your contrary choice. And that results in gridlock. Your choices block my choices. Your world-segment can’t coexist with my world-segment.