Physicist Unveils a 'Turing Test' For Free Will 401
KentuckyFC writes "The problem of free will is one of the great unsolved puzzles in science, not to mention philosophy, theology, jurisprudence and so on. The basic question is whether we are able to make decisions for ourselves or whether the outcomes are predetermined and the notion of choice is merely an illusion. Now a leading theoretical physicist has outlined a 'Turing Test' for free will and says that while simple devices such as thermostats cannot pass, more complex ones like iPhones might. The test is based on an extension of Turing's halting problem in computer science. This states that there is no general way of knowing how an algorithm will finish, other than to run it. This means that when a human has to make a decision, there is no way of knowing in advance how it will end up. In other words, the familiar feeling of not knowing the final decision until it is thought through is a necessary feature of the decision-making process and why we have the impression of free will. This leads to a simple set of questions that forms a kind of Turing test for free will. These show how simple decision-making devices such as thermostats cannot believe they have free will while humans can. A more interesting question relates to decision-makers of intermediate complexity, such as a smartphone. As the author puts it, this 'seems to possess all the criteria required for free will, and behaves as if it has it.'"
Oh, not again. (Score:4, Informative)
Again, someone ran into the halting problem and thought they could say something profound about it. Worse, they got tangled up with "free will", which is theology, not physics or compute science.
A deterministic machine with finite memory must either repeat a state or halt. The halting problem applies only to infinite-memory machines. A halting problem for a finite program can be made very hard, even arbitrarily hard, but not infinitely hard.
As a practical matter, there's a widely used program that tries to solve the halting problem by formal means - the Microsoft Static Driver Verifier. [microsoft.com] Every signed driver for Windows 7 and later has been through that verifier, which attempts to formally prove that the driver will not infinitely loop, break the system memory model with a bad pointer, or incorrectly call a driver-level API. In other words, it is trying to prove that the driver won't screw up the rest of the OS kernel. This is a real proof of correctness system in widespread use.
The verifier reports Pass, Fail, or Inconclusive. Inconclusive is reported if the verifier runs out of time or memory space. That's usually an indication that the driver's logic is a mess. If you're getting close to undecidability in a device driver, it's not a good thing.
According to this test.. (Score:4, Informative)
Humans don't have free will. There's no reason to believe the answer to question #4 is no. The neurons composing our brain deterministically (given a specieid set of stimuli, they had a calculatable response). With sufficient knowledge on the layout and state of someone's brain, you could calculate what their response to a given stimuli would be.