List on Free Will and Determinism (Part Two)

(Part One)

This is the second part in my series looking at Christian List’s article “Free Will, Determinism and the Possibility to do Otherwise”. The goal of List’s article is to provide a new compatibilist theory of free will. This, he argues, requires a theory of agency that allows for alternative possibilities. In part one, we saw how he dismisses the conditional and dispositional theories of alternative possibilities and opts for the modal theory of alternative possibilities. In this part, we will see how he develops a theory of agency that is compatible with this modal theory of alternative possibilities and with the determinist theory of causation.

List’s article uses a number of technical flourishes to support his basic argument. In many ways, these technical flourishes are what makes his article a unique and significant contribution to the literature. However, I’m going to avoid them in my summary and just share the key elements of the basic argument. If you want the supporting detail, read List’s article.


1. What does List Want to Establish
Before we get down to the main argument, we have to do a little bit of grunt work. To be precise, we have to clarify the main objective of List’s argument. We start by considering a simple argument against the compatibility of free will and determinism:

• (1) Free will requires that (at the time of interest) more than one alternative course of action is possible for the agent.

• (2) Determinism implies that (at the time of interest) only one course of action is possible for the agent.

• (3) Therefore, free will and determinism are incompatible.

Following the discussion in part one, premise (1) is here understood to involve the strong modal sense of alternative possibility. List has no wish to challenge this premise here. His concern lies with premise (2), which, he believes, is misleading. He thinks that determinism is primarily a thesis about possibility at the fundamental physical level of reality, not a thesis about possibility at the agential level of reality.

In other words, he thinks we need a new premise that more accurately describes the determinist thesis:

• (4) Determinism implies that (at any given time) only one future sequence of events is physically possible.

And he thinks we need to see whether (4) actually implies (2). The incompatibilist will, no doubt, assume that determinism at the physical level implies determinism at the agential level, but that is an assumption that List wants us to challenge. He wants to show us how to sever the assumed connection between (4) and (2).


2. List’s Basic Argument
Now that we know what List wants to do, let’s see how he goes about doing it. His argument is relatively straightforward. It relies on several claims that are widely accepted within the philosophy of mind and the sciences of human behviour. These claims have to do with the relationship between agential states and fundamental physical states. He starts by defining an agential state as:

Agential State : The state of an agent and his or her macroscopic environment as specified by a relevant higher level theory of human behaviour.

List gives some idea of what he means by “a relevant higher level theory of human behaviour” later in the article. He reckons our best available theory of human agency is some version of behavioural decision theory. This theory posits the existence of intentional states such as beliefs, desires, preferences, intentions and so forth, and uses these states to explain and predict human behaviour.

Agential states, so defined, have two key features:

Supervenience : agential states are supervenient upon physical states. This means that there cannot be variations in agential states without there also being changes in physical states.

Multiple Realisability : There is typically more than one physical state that gives rise to the same agential state. Which is to say: not every variation in a physical state gives rise to a variation in an agential state.

Both of these features are widely accepted within the philosophy of mind, although some reductionists will deny them (e.g. John Bickle). We’ll say something more about reductionism in a moment, for now we’ll follow List and use these two features of agential states as the basis for the following argument:

• (5) If a state of Type X (call it “X1”) is multiply realisable by states of Type Y (Y1…Yn), then the existence of X1 is consistent with the existence of more than one state of Type Y (i.e. Y1…Yn, where n ≥ 1).

• (6) Agential states are multiply realisable by distinct physical states.

• (7) Therefore, the existence of any particular agential state (e.g. “belief that P”) is consistent with the existence of more than one distinct physical state.

• (8) Determinism is the thesis that for every temporally and spatially identical physical state there is only one possible future and for every temporally and spatially distinct physical state there is more than one possible future.

• (9) Therefore, the existence of any particular agential state is, despite the truth of determinism, consistent with more than one possible future.

• (10) Therefore, from the perspective of the agent, determinism does not imply a lack of alternative possibilities.

This argument is slightly inelegant — a result of my cobbling it together from several pages of List’s article — but I think you get the gist: because of multiply realisability, agential states are, despite the truth of determinism, consistent with more than one possible future.

List uses two devices to further flesh out and defend this basic argument. One of them is a “toy model” of physical reality which illustrates exactly how the same agential state could be realisable by different physical states and could thereby be consistent with multiple possible futures. If you’ve ever read Dennett’s Freedom Evolves you’ll be familiar with toy models of this sort. I think List makes better use of his toy model than Dennett did with his. One important lesson to be drawn from List’s toy model is that an agential state is not always going to be consistent with multiple possible futures, but, rather, that can sometimes be consistent with multiple possible futures.

The second device used by List is his analysis of the special sciences of human behaviour. Appealing to behavioural decision theory as the best available theory of human agency, List argues that this theory presupposes that every agent faces alternative possible futures. Indeed, he argues that the analysis of decision problems or strategic interactions (games) makes little sense without such a presupposition. The suggestion here seems to be that, if such a presupposition operates in these sciences, and if multiple realisability is true, then we can remain confident in the existence of alternative possible futures, at least from the agential perspective.


3. Further Issues
List notes two ways in which his argument could fail to impress. The first would be if there was some one-to-one reductive relationship between agential states and physical states. Such a relationship would mean that multiple realisability was no longer true. And if multiple realisability was no longer true, a single agential state would no longer be consistent with multiple possible futures. As I noted above, some hardcore reductionists like John Bickle make this claim.

The other way in which List thinks his argument could fail is if the sciences of human behaviour reject the presupposition of alternative possible futures. In other words, if they establish that each agential state is actually only consistent with one possible future. This has actually happened at various times throughout the history of the behavioural science (e.g. behaviourism was quite deterministic at the agential level), so we should perhaps be on the lookout for this.

I have a further issue I want to raise. Although he explicitly excludes the issue from his analysis, I’d love know what the implications of his argument are for moral responsibility. My feeling is that it wouldn’t do anything to address the concerns of those who think that determinism is incompatible with moral responsibility. Here’s my thinking: List’s argument really only establishes that there a multiple possible futures open to an agent at the time of their decision making. That is to say, it shows that when you are presently in agential state A, you have multiple possible futures open to you. The argument does nothing to show that when you look back at when you were previously in agential state A, you had multiple possible futures open to you.

To explain further, the act of holding someone responsible generally viewed a third-person, backward-looking act. In other words, it is an act in which one agent examines the historical decisions of another agent and asks whether that agent was responsible for that historical decision. But if alternative possibilities at that historical moment are necessary for moral responsibility (a condition I’ll concede for now), then List’s argument does nothing to show that they were available to the agent. List’s argument only shows that multiple possibilities are available to the agent from a first-person, forward-looking perspective.

Am I right about this, or am I being unfair to List’s argument? Tell me what you think.