Sunday, December 26, 2010

Who's Still Afraid of Determinism? (Part 2)

(Part One)

In the previous entry we took a look at the motivations behind D & T’s article and outlined some of the formal concepts they use in making their arguments. In this entry, we turn to the arguments themselves.

These arguments respond directly to the alleged problems with determinism. As you recall, these were (a) that determinism rules out any meaningful sense of alternative possible futures; and (b) that determinism rules out any meaningful sense of originative causal powers.

Let’s see why D & T think those concerns are misplaced.

1. Determinism and Alternative Possible Futures
Dennett thinks that the following famous footnote in one of J.L. Austin’s essays sums up the incompatibilist position on alternative possible futures:

"Consider the case where I miss a very short putt and kick myself because I could have holed it. It is not that I should have holed if I had tried: I did try, and missed. It is not that I should have holed it if conditions had been different: that might of course be so, but I am talking about conditions as they precisely were, and asserting that I could have holed it."

In this short paragraph, Austin is making a claim about what it is possible for him to do. In the previous entry, we saw that such statements are characterised by their appeal to possible worlds. So, roughly, what Austin is saying here is that the sentence “Austin holes his putt” is true in at least one possible world within a specified subset (X) of possible worlds.

The big problem for Austin is how large the specified subset X needs to be in order for him to meaningfully claim that he “could have holed the putt”. In the portion quoted above, Austin seems to include just one world in the subset X: the actual world in which we live (“conditions as they precisely were”). D & T call this the “narrow” approach and think it is typical of the incompatibilist position.

D & T’s contention is that the narrow approach is flawed: to make meaningful claims about what is possible, we have to have a broader interpretation of the subset X. Indeed, Austin himself seems to be aware of this because after the section just quoted he continues in the following manner:

“Further experiments may confirm my belief that I could have done it that time, although I did not.”

If Austin sticks to the narrow approach, “further experiments” are meaningless since they occur in a different set of conditions. Only if he takes the broader approach would such a claim make sense.*

D & T reinforce this observation with a lengthy thought-experiment about two chess-playing computers. Anyone who has spent time reading Dennett will know that, along with Conway’s Game of Life, this is one of his favourite “intuition pumps”. Apparently, there is no concept in the philosophy of mind, biology and responsibility that fails to be illuminated by it.

I won’t repeat the lengthy discussion of the chess-playing computer programmes here. Suffice to say, the important point about such programmes is that they are “miracles of determinism”: they play chess games in accordance with predetermined algorithms. Nevertheless, they can they can play different sequences of games if they make use of pseudo-random number-generators. Each one of those games is a possible world (in a subset X), and each one reveals something about the competencies and capabilities of the computer programme. Or, to put it another way, the games reveal something about what it is possible for the programmes to do. This is a meaningful sense of possibility, and it is based upon a broad construal of the set X.

D & T argue that these observations make discussions of possibility perfectly compatible with a deterministic worldview. The ball is thus sent back to the incompatibilist’s court: they must show why indeterminism is necessary.

2. Making a Difference in a Deterministic World
The second worry that incompatibilists have about determinism relates to causal powers. To recap, the concern is that determinism leads inexorably to the view that human beings are mere receptacles through which non-human causal forces exert their powers. D & T obviously think this is wrong and they do so on the basis of a simple argument:

  • (1) Determinism is a thesis about causal sufficiency, not a thesis about causal necessity.
  • (2) For meaningful, morally relevant causal powers, we care about causal necessity, not sufficiency.
  • (3) So, the truth of determinism does not remove or eliminate the kinds of morally relevant causality that we care about.

Premise (1) could be taken as a stipulative definition of what determinism is, however, that may be a little unfair since it also tracks well what I have read elsewhere. D & T say the definition amounts to something like the following:

If σ1 is a (mind-bogglingly complex) sentence that specifies the state of the universe at t1, and σ2 is another sentence that specifies the state of the universe at t2, then determinism dictates that σ1 is sufficient for σ2 in all physically possible worlds.

What does this definition actually mean when making a causal judgment with practical implications?

D & T look to the example of JFK’s assassination by Lee Harvey Oswald. According to determinism, the condition of the universe one instant after the big bang (call this “σ”) sufficed to produce the death of JFK in November 1963 (call this “ψ”). But, argue D & T, this tells us nothing about what actually caused Kennedy’s death, or who bears responsibility for his assassination.

This is because although σ is sufficient for JFK’s assassination, it is not necessary. JFK could have been assassinated even if σ were other than what it was. The necessary preconditions of the assassination included things like “Lee Harvey Oswald was born” and “Oswald pulled the trigger of his gun” and so on, not the complete description of the microphysical properties of the universe one instant after the big bang.

This example allows us to see why the incompatibilist fear of determinism is misplaced: when we are interested in explaining why something happened, or in figuring out who bears responsibility for it, we are primarily interested in what is causally necessary, not what is causally sufficient. This is what is asserted in premise 2. The conclusion follows as a matter of course.

This brings us to the end of D & T’s main article. They have now, to their minds, shown why there is nothing to fear from determinism and why incompatibilists bear the burden of proving otherwise. They have an appendix in which they deal with Peter Van Inwagen’s famous Consequence Argument. I’ll look at that in the next entry.

* I sometimes like to employ a explicability argument in response to those who make use of the narrow approach. As follows: Suppose one does accept the narrow approach, and suppose the one world within the set X does give rise to alternative possible futures. Ask yourself: what is making the difference in realising these possible futures? By stipulation, it can’t be anything in your personality or psychology because if they were different, conditions would not be “precisely as they were”. So what could it be? The answer: nothing that is relevant to an ascription of responsibility. Is this a good argument? I think so, but I'd be interested in hearing counterarguments.


  1. A little confused here...

    D&T say that the narrow approach is flawed because they can't make meaningful claims about what is possible, but isn't this exactly what was intended by using the example with the exact same conditions, that only one outcome was ever possible? If the conditions at the beginning of the universe (the random number) is σ and the laws of physics (the algorithm) are the same then would JFK not die every time(the game would play out precisely the same)?

    Also, does the condition σ being sufficient but not necessary mean that σ does not necessarily lead to ψ or that ψ can be caused by ~σ?

    Surely in the narrow sense σ necessarily leads to ψ?

    Essentially, I don't see how they are justified in making comparisons about what could have happened given different initial conditions - It would be like saying the golfer could have made the shot if the grass was at a different angle, or JFK would have lived if the car was travelling slightly faster.

    Does this not defeat the purpose of the whole exercise?

  2. I think the major source of confusion may have come from how I framed the article in part one. I originally suggested that D & T were concerned with the metaphysical side of the free will debate, but in retrospect this was a mistake. They are not concerned with this at all, they are concerned with the existential and moral implications of determinism. Reframing it in this way could help to answer some of your questions.

    As for your specific questions:

    (1) Re: the point of examples such as Austin's Putt.

    I would say the point of such examples is most definitely not to say that only one outcome was ever possible. That certainly doesn't seem to be what Austin is saying in the quoted passage. Indeed, he is saying the opposite: that other outcomes are possible even in exactly the same circumstances or at least it feels that way to him. John Searle makes very similar assertions in his writings on free will. I think the real point of those examples is to show that meaningful claims about what it is possible for agents to do must adopt the narrow method. D & T are targetting this claim directly, they are not going after the metaphysical meaning of such a claim.

    (2) Re: the fact the "game" would play out precisely the same.

    This is no doubt true, but also, I take it, irrelevant to the kind of argument D & T are making. Their point is that σ doesn't tell us why the assassination takes place. This is because it is a causal claim or explanation without practical implications. And since only explanations with practical implications affect our moral/existential lives, σ is not something that affects our moral and existential lives.

    I think Dennett also brings to the table certain arguments that he has made elsewhere about the practical irrelevance of complex but highly accurate micro-physical explanations. I'd suggest reading his article entitled "Real Patterns" on this.

    (3) Re: sufficiency and necessity.

    The second part of your disjunct is the correct one, i.e. that ψ can be caused by not-σ.

    Re: your other question about making comparisons across different possible worlds.

    I think the point (and this comes across better in the chess-playing computer story) is that we can't really make claims about the universe as a whole; we can only make claims about experimental possible worlds (with varying initial conditions) that we create. If we limit ourselves to these worlds then it would seem like claims about putting or assassinations under different conditions are legitimate. This is why D & T don't offer a full account of possible worlds, only one that is compatible with scientific approaches to explanation.

    I think Dennett would also argue that it is claims about these experimental worlds that carry all the weight in our practical and moral lives. For example, the theory of responsibility that he presents in his book Freedom Evolves is not really focused on how an agent performed a particular act in the past, but on the causal powers of the agent across a range of experimental possible worlds.

  3. "The necessary preconditions of the assassination included things like “Lee Harvey Oswald was born” and “Oswald pulled the trigger of his gun” and so on"

    Eh, no they aren't. Necessary preconditions, that is. They are sufficient conditions, but the assassination surely could have happened in another way.

    This doesn't detract from their major point, that we should focus on the chain of events that led, sufficiently, to the assassination. I think they may very well be correct that this is a good way to think about causation, but that they don't address the real worry the incompatibalists assert. You may be able to define a "choice" using imaginary worlds, but I believe the incompatibalist will maintain that this isn't a "real" choice. These worlds are imaginary, you can't really choose to go to them. So you can't really hold a person morally accountable for not going there - he never had a "real" choice whether to go there or not.

    Now, I think that's bullocks as it intentionally wraps a black curtain over the process of choosing. A person's choice only carries moral weight if it reflects his moral thinking, and hence choices are only meaningful to the extent that they reflect deterministic thought processes. The "real" choice the incompatibalist wants is not a choice at all, it's a metaphysical impossibility borne by not describing the process of choice.

    In terms of your conceptual framework: strong intelligability precludes strong alternativism, making strong free-will incoherent.

    D&T address Alternativity, but they fail because their "choices" are not between two real alternatives (from the incompatibalist's point of view).

    I would also like to add that I hate counter-factuals and possible worlds. I concede that this is probably the way to think about causation, but I want to emphasize that this is closely related to the uniformity of the laws of nature, which are assumed to apply to the alternative imagined worlds. Causation only makes sense due to the regularity in the behavior of nature. This is the only way we can conclude that had Oswald not been born, say, he wouldn't have killed the president. Ironically, this regularity is only a partial picture of reality. Causality doesn't really exist - quantum events just happen, with some frequencies, and "causal power" is a level of description we apply to this sordid mess. I isn't really applicable in some cases (e.g. vacuum fluctuations). The universe, as Russell put it, just is.

  4. Hi Yair,

    Sorry for the delay, the past week has been pretty busy.

    As regards what is a necessary condition, you are right. I just took down those examples from the article without really thinking it through. I'll have to re-read it to see what Dennett and Taylor were talking about.

    I appreciate your trying to get at things from the incompatibilists point of view and your concern about possible worlds. If you're interested, you might like the following article by Laura Ekstrom which argues that compatibilists shouldn't use the counterfactual theory of causation:

    Ekstrom, L. "Freedom, Causation and the Consequence Argument" (1998) 115 Synthese 333-354

    I'll be going through a whole raft of papers on free will over the next few weeks and months and will get to hers eventually (if you want to wait til then).

  5. Yair,

    I read back over that section of the D & T article. I think, alas, the best explanation for the problem you pointed out is that I, somewhat ironically, conflated two aspects of what they were saying.

    They do say that necessity is more important in causal explanation, and they do say that "Oswald pulled the trigger" and "Oswald was born" are more plausible causes of JFK's assassination than the complex description of the universe a few moments after the big bang, however, they do not say that these "more plausible" causes are necessary.

    My bad.

    I would add that what counts as a necessary cause is dependent on how we select the set of possible worlds included within the scope of our causal claims. If we have a relatively (but not entirely) narrow construal of the set of possible worlds, then something like "Oswald pulled his trigger" might come much closer to being a necessary cause.

    Some of this was discussed in Part 1.