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Monday, January 6, 2014

Misconceptions about QM and free will

Swedish physicist Sabine Hossenfelder posts 10 Misconceptions about Free Will:
If somebody talks about a “question that science cannot answer” what they really mean is a question they don’t want an answer to. Science can indeed be very disrespectful to people’s beliefs.
No, saying that science cannot answer a question means that there is no experiment or set of observations to resolve the question.

Are sunsets beautiful? Is Obamacare a failure? Is P = NP? These are legitimate questions, but science cannot answer them.
“Do humans have free will?” is a question I care deeply about. It lies at the heart of how we understand ourselves and arrange our living together. It also plays a central role for the foundations of quantum mechanics. In my darker moods I am convinced we’re not making any progress in quantum gravity because physicists aren’t able to abandon their belief in free will. And from the foundations of quantum mechanics the roadblock goes all the way up to neuroscience and politics.

Yes, I just blamed the missing rational discussion about free will for most of mankind’s problems, including quantum gravity.
There you have the folly of modern physics in a nutshell. Yes of course free will lies at the heart of how we understand ourselves. Yes, free will plays a central role for the foundations of quantum mechanics, as QM is unique among modern science theories in that it accommodates free will, as shown by the free will theorem.

But no, an Eisnteinian belief in determinacy will never lead to any progress in quantum gravity.

She lays bare her illogical argument:
So, first the facts.

Fact 1: Everything in the universe, including you and your brain, is composed of elementary particles. What these particles do is described by the fundamental laws of physics. Everything else follows from that, in principle. ...

Fact 2: All known fundamental laws of nature are either deterministic or random. To our best present knowledge, the universe evolves in a mixture of both, but just exactly how that mixture looks like will not be relevant in the following.

Having said that, I need to explain just exactly what I mean by the absence of free will:

a) If your future decisions are determined by the past, you do not have free will.

b) If your future decisions are random, meaning nothing can influence them, you do not have free will.

c) If your decisions are any mixture of a) and b) you do not have free will either.
It would be understandable if she said this in the 19th century. But QM is our leading theory, and it teaches that future decisions are not determined by the past, and that they are only random in the sense of not being predictable by others. In other words, QM is completely compatible with free will.

If you think that QM is somehow incompatible with free will, ask yourself this question: Is it possible for any physical theory to be more compatible with free will than QM? I do not see how. Free will is baked into QM.

If the answer is yes, then ask why no one has ever proposed such a theory. If the answer is no, and you still oppose free will, then your opposition to free will is purely philosophical and independent of any physical principles.

Some ancient philosophers opposed free will, so it is possible to take such a view. Just do not pretend that the view is informed by science, because it is not.
The conflict that doesn't go away is this: There's no sense in which you can change your future. ...

"I could go and jump out of a window. That would change my future dramatically."

No it wouldn't. Your future either does or doesn't contain you jumping out the window. There's nothing you can change about that.
The root of her problem is that she does not believe in counterfactuals. She rejects a concept that is easily understood by little kids. I will post more on that.

She believes in Einsteinian determinism, and even likes superdeterministic hidden variables theories, more commonly known as "conspiracy theories".

Lumo addresses her misconceptions one by one.

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