Monday, August 8, 2011

The 'Horace' Simulation

propositional posts:
Deterministic Compatibilism

Let's say you meet up with a prophet (so he calls himself) named Horace.

Scenario 1: Horace the Fraud

In this scenario, Horace writes something down on a piece of paper, and then asks you to choose a number between 1 and 100. You do so, and Horace reveals what he wrote. It matches what you chose! You repeat the exercise again and again, and each time Horace is right.

In this scenario, metaphysical Libertarianism is true; our choices are not the result of antecedent causes, and instead proceed from some transcendent self. Knowing this, you press Horace for an explanation. Horace reveals that it was just a magic trick. He waited until he heard your number, and then used sleight of hand to produce a piece of paper that matched what you picked.

Scenario 2: Horace the Real Deal

In this scenario, Horace writes something down on a piece of paper, and then asks you to choose a number between 1 and 100. You do so, and Horace reveals what he wrote. It matches what you chose! You repeat the exercise again and again, and each time Horace is right.

In this scenario, Determinism is true; the universe (including our selves) works according to mechanistic laws of cause and effect. Furthermore Horace, who has divinely-powerful faculties of comprehension and prediction, is able to understand and interpret every minute detail of that Deterministic universe, and is thus able to make 100% accurate predictions about everything that happens within.

The 'Fraud' Simulation

I can write a computer program that simulates the first scenario. Virtual Horace appears to write something down, you choose a number, Horace's number is revealed, and it matches yours.

The 'Real Deal' Simulation

The simulation of the first scenario, it turns out, is also a perfect functional simulation of the second scenario! It fully accounts for all inputs and outputs.

The Dilemma

Metaphysical Libertarians define free will such that in scenario 1, you have a measure of free will, but in scenario 2, you don't.

But your experiences under both scenarios are exactly the same. This is shown by the fact that both scenarios can be simulated by a single simulation.

The Rejection (of Libertarian Free Will)

The Libertarian notion of free will is nonfunctional. This nonfunctionality is a sign of its incoherency.

The Defense (of Compatibilist Free Will)

Your ability to choose any number you want is preserved whether or not Determinism is true.

Moving from Scenario 1 to Scenario 2 does not cause that choicemaking to become "illusory," "false," or "non-actual," unless the distinctions between real & illusory choices, true & false choices, and actual & non-actual choices are nonfunctional and meaningless. And, of course, if we accept that those distinctions are nonfunctional and meaningless, it follows that it's silly to use them.

7 comments:

shopkins said...

I don't think libertarians are beyond accepting scientific evidence. But in order to support the claim that human behavior is 100% predictable or deterministic, you'd have to be able to predict it with 100% accuracy. You're assuming we have this capability. I don't think there is anywhere near a consensus that we do.

But beyond that, it's strange to claim that because the "inputs and outputs" are the same, the scenarios are identical, or 'functionally' identical, and thus any distinctions are meaningless. To see why this is clearly the case, say Horace1 rolls 100-sided dice to make his guess and happens to get your number every time. Whereas Horace2 consults his handy Human Behavior Guide and calculates what your number will be. In both cases the "inputs and outputs" are the same, but they seem strikingly different.

Or another example: say you're presented with a situation where you could lie to your personal advantage. In Outcome 1, you decide to lie through normal decision making processes. In Outcome 2, you at first decide NOT to lie, but a chip implanted in your brain by a mad scientist overrides your decision and forces you to decide to lie. These outcomes seem functionally identical, and yet I think most people would say, at least at first blush, that they represent very different moral values.

shopkins said...

Also, it's wrong to say that libertarians "define free will" or have a "libertarian notion of free will." Libertarians aren't talking about libertarian free will and compatiblists aren't talking about compatiblist free will. The free will thesis that the two are arguing over is the same. Compatibilism is just the claim that free will (and free will full stop, regular old free will) is compatible with determinism, and incompatibilism the claim that regular old free will is incompatible with determinism. (Libertarianism is incompatibilism combined with the claim that free will exists, but what you're really arguing against is incompatibilism so it'd be better to stick to using that term.)

Peter Van Inwagen has the best introduction to the problem of free will I've ever read, and, though he is an incompatibilist, he casts the problem in what seems to me to be extremely neutral terms: http://www.springerlink.com/content/9477m06522206w67/ . He has a lot of praise for David Lewis, a noted compatibilist.

Stan Patton said...

p1: How can you say I assume we have this capability? It is, in fact, my belief that we'll never have this capability. What led you to believe I was assuming otherwise?

p2: They are strikingly different, but functionally the same. And since they are functionally the same, this should lead you to conclude that the die is magically weighted, or any number of infinite explanations that make the scenario functionally identical to true prophecy. That there are infinite ways to make a functionally identical scenario is not problematic in any way.

p3: This is a moral issue, not a functional issue, as you found yourself admitting in the final sentence.

p4: The more I argue with libertarians, the more I find that the free will theses over which the two sides are arguing are not at all the same, and that there are two (and more) definitions (and attempts thereat) of free will between them. As convenient as it would be to start from a "regular old free will" common ground, I find, after 10 years of this stuff, the hope or expectation of this to be naive.

p5: I'll check it out.

shopkins said...

Again, compatibilists and incompatibilists are not arguing over the free will thesis. Generally, both sides accept that free will exists (or more technically, that the free will thesis is true), but that is irrelevant to the discussion. They are arguing over whether that thesis is compatible with determinism. If there were not a basic notion of what the free will thesis entails, there could not even be a coherent debate. But when you attempt to "define" free will in a way you think amiable to compatiblism (or when you show that an incompatibilist "definition" of free will is wrong-headed), you must be appealing to some more basic idea of what we mean by free will, and of course THAT is what we mean by the free will thesis. I think Van Inwagen is more or less correct when he says the free will thesis is that someone at sometime had the ability to do A or not do A.


"And since they are functionally the same, this should lead you to conclude that the die is magically weighted, or any number of infinite explanations that make the scenario functionally identical to true prophecy."

- Why shouldn't the same logic lead me to conclude, if the Human Behavior Guide has the functional properties of rolling a die, that somewhere it implements a dice-rolling algorithm?

Stan Patton said...

"If there were not a basic notion of what the free will thesis entails, there could not even be a coherent debate."

The 'water thesis' entails 'that wet stuff that we drink,' and the debate is between whether that thing is One of the Four Elements or dihydrogen monoxide.

Similarly, the 'free will thesis' entails 'that feeling of spontaneous, unconstrained procession of our wills,' and the debate is whether that thing is Our Transcendent Self-Causation or whether it is a phenomenal combination of the fact that we have no conscious apprehension of the things from which consciousness emerges (as one would expect) combined with the patterns we notice when desirers are (or aren't) oppressed or coerced.

In some ways, it's not about the definition. In other ways, it's all about the definition.


"I think Van Inwagen is more or less correct when he says the free will thesis is that someone at sometime had the ability to do A or not do A."

That "or" is really a hidden "xor," since you cannot do both A and !A. Under Determinism, "someone at sometime had the ability to do A xor !A" is true, even if that person was predetermined to do !A.

Skurvy2k said...

Hello Stan.

Skurvy2k said...

Hello Stan.