Of course, this may all be a long-winded preface to a "Bam! You atheists can't believe in free will without god by the rules of your godless universe, so if you believe in free will you HAVE to believe in god!!!" sucker punch. I don't think its mhaberling's style, to be honest - and as a non-believer in free will that punch holds no worries for me anyway! - but I can see why it could be a fear.
I don’t see why it would be a problem either. If mhaberling shows there is no free will in this universe by proving that it is physically impossible then the same applies to him and he would also be proving that his god couldn’t have granted free will. Showing that there is free will in this universe in no way proves it is a gift from any god or that any god exists.
Mhaberling's point, I believe, is "how do we KNOW that these allegedly random events are indeed random, and not following some specific causal rules that we are currently unable to determine?" To take the dice analogy, I'm sure there was a point way back when when we thought the roll of a dice was random, as opposed to completely causal and predetermined, albeit unpredictable. I confess I'm not up enough on quantum theory as I might like - is there an "idiot's guide" that shows how it is provably random?
As far as I know, there is no test to prove something is
, but there are tests
to prove something is not random. If those tests fail to show that a phenomenon is predictable or non-uniformly distributed then it is considered to be random.Here
are some notes on quantum indeterminacy explaining why quantum events are unpredictable, even in principle.
I think to be honest you are both on the same page - from where you say "Random means unpredictable, not uncaused. Yes, everything has a cause, but some of those causes are unpredictable in one way or another". I believe that that is the point he was making - that there are quantum events that are singularly unpredictable, but that if we could "go back in time" to the same point, would that quantum event happen differently? Or, if you prefer, can a particular quantum event potentially happen in two or more different ways, or can it ONLY happen in one specific (but completely unpredictable) way? (Bolded that bit because (a) I don't know the answer(!), and (b) I think its crucial to the argument. I thought the answer was "two or more", but from what you said I'm now not sure!)
Mhaberling is arguing that if we knew all the algorithms and conditions, we could, in principle, predict the outcome of all future events and decisions we may make and we could trace those events and decisions all the way back to the big bang. Therefore, everything is predetermined and we have no free will. Quantum indeterminacy shows us that we cannot
know all the conditions, even in principle, because they are actually unknowable. To answer your first question, if we could go back in time to the same point where a quantum event occurred and went forward again, then it could have happened differently. To answer your bolded question, yes, a particular quantum event can happen in two or more different ways and in some cases those quantum events affect events in the macroscopic world. Let me give you a real-world example.
In an earlier post, I mentioned that in some telephone exchange equipment routes are selected randomly using radioactive decay as the mechanism. Here’s a little more detail. In Ericsson ARF exchanges (older crossbar exchanges) the marker (decision making equipment) in the group selector stage selects a route from those available using radioactive tubes. Each tube has a speck of radioactive material inside that is slowly ionising the gas in the tube. When a route is to be selected, a voltage is applied across all the tubes in parallel and the one with the highest ionisation potential fires, selecting that route. This discharges the ionisation in that tube so on the next selection it is at the bottom of the pile. The ionisation potential is dictated by how many atoms have decayed over a period of time. That is completely unpredictable due to quantum indeterminacy so even if we could replay events, another tube may have fired instead.
Now, the available routes all give a path to the destination for any particular call, but what if one of those routes is faulty and it is the one that happens to be selected? In that case, you get a no progress call. You dial the number and get nothing—no ring tone, no busy tone—just an open line. I’m guessing you’ve had this happen to you. After some time you may receive some failure tone. What do you do? Normally, people will hang up and dial again. So here we have a situation where there were two possible outcomes governed by quantum indeterminacy: one tube fired and selected a usable route or another tube fired instead and selected a faulty route. This led to the caller acting differently. They either held the call or dialled again—or maybe didn’t bother to dial again. So here we have an action someone made that cannot be traced all the way back to the big bang no matter how hard we try. It was determined entirely by what occurred only one second before. The future branches right there and who knows what consequences the failed call may have. These sorts of events are happening all the time in many different ways so it just isn’t true to say the cause of every action we take can be traced all the way back to the big bang.
My summary: my position was that 99.999% of things were causal, with (perhaps) some potentially TRULY random quantum level things being put into the mix which would make prediction imposible, even were some mechanism for prediction possible. I may now have to change that to EVERYTHING is causal, including quantum happenings, but it all remains unpredictable due to limitations on what we can calculate.
Either way, I see no "free will" aspect to things. Causal or random, I still am unable to undestand where "choice" (in the "I could do different things in identical circumstances, in a way that is directed by 'me' rather than being the result of 'non-me randomness' ") comes into play.
Everything has a cause, but that cause may be unpredictable and may immediately precede the event with no path back into the past. Here are a couple of situations where you could do different things in identical circumstances. For a start, think about whether you have ever changed your mind when making a choice even though the circumstances haven’t changed. Here are some other situations. You are walking through the supermarket and you pick a can of peas (or whatever) from the shelf. There are many identical cans on the shelf (same brand, same product, same use-by date). Couldn’t you have picked a different one? You are at a party or a restaurant and a magician comes up to you, fans a deck of cards face down in front of you and asks you to pick one. They all look identical. You pick one somewhere in the middle. Couldn’t you just as easily have picked one either side of the one you chose? Did you make those choices or were they dictated by some non-you randomness?