Wow! As a big Stephen Hawking fan, I never thought that I'd write a blog post where I took him to task for getting a scientific subject wrong.
But after watching Episode 3 of Hawking's new "Genius" series, I've got to point out how confusing this Why Are We Here? episode was when it came to free will.
I've read a lot about free will. I've thought a lot about free will. I've written a lot about free will. (For example, see here, here, and here.)
So I was all eyes and ears as Hawking led three ordinary people -- meaning, non-scientists -- through exercises designed to get them thinking in a scientific way. Clips can be viewed on the PBS web page devoted to Episode 3, along with the entire hour long show.
We see them marveling at floating plates in a room within an English castle. Not surprisingly, this isn't the result of magic, but magnetism. The lesson learned is that scientific understanding of the laws of nature is the way to comprehend the world, not supernatural explanations.
Then the three Genius explorers tackle a difficult problem: how to knock an olive on a toothpick that's balanced on the edge of a cocktail glass into the drink. Without touching it with their hands.
A pendulum device on a long chain looks promising. The swinging round ball definitely has what it takes, but the scientific students keep either missing short (no contact) or long (too much contact, so the glass breaks). After many tries, and many refills of the drink by a bartender in the room, they figure out what to do.
Use a board with markings to get the ball in a precise spot, and use a button that deactivates a magnet holding the ball in place so the "push" on the ball is exactly the same every time. It doesn't take long for them to find the sweet spot where the olive is gently knocked into the glass.
And they can do this repeatedly. Lesson: if something is done in exactly the same way, the same thing will happen according to the laws of nature.
A replication of the famous Libet experiment about conscious vs. unconscious choice gets us directly into questions of free will. The three people are asked to push a button (which sets off fireworks!) at a moment of their choice while staring at a large clock projected onto a castle wall.
They note the time they consciously chose to push the button. As Libet found, and as other researchers have confirmed, a conscious decision to do something is preceded by unconscious activity in the brain. So this teaches the threesome that free will doesn't really exist, since the sense of "I freely choose to do this" is an illusion.
Actually, brain processes outside of our awareness determine what we choose. Thus they learn that determinism resulting from the laws of nature rules the universe, and us.
I was nodding along agreeably with Episode 3 up to this point. The points Hawking was making seemed eminently justified, being in line with familiar scientific principles I'd read about in numerous books and articles.
But then the episode took a turn.
A Doppelganger challenge featured many people wearing masks of the three Genius explorers. They lined up behind the real person. Then each individual decided to take a step to the right or left when a loud "beep" sounded. Before long these choices resulted in the Original and Doppelgangers being considerably out of step with each other, so to speak.
The lesson Hawking was teaching here struck me as way more scientifically problematic than what had been presented before. This exercise pointed to the Many Worlds (or Many Universes) theory of quantum mechanics.
As a Wikipedia article discusses, the notion that all possible outcomes occur, that the "universe splits into all possible universes all the time" (as Hawking says near the end of Episode 3) is by no means a settled understanding of science. The Many Worlds interpretation of quantum mechanics has a lot of fans, but the article quotes a critic: "And who here believes the laws of physics are decided by a democratic vote?"
Yet Hawking and some other scientists, such as physicist Sean Carroll, speak as if it is virtually certain that every possible action or choice does occur in a parallel universe.
Now, obviously there's no problem entertaining this hypothesis. It makes a lot of sense, and resolves some difficult questions about the quantum world. My problem is with how Episode 3 related free will to the Many Worlds theory. I failed to see how everything happening that could happen saves free will, as one of the threesome seemed to believe.
After all, Hawking had just led the three people to several understandings: the laws of nature rule the universe, and unconscious brain processes determine our conscious choices.
So someone decides to step to the right when hearing the beep in the Doppelganger exercise. This wasn't a freely willed choice. Yet certainly a different choice -- step to the left -- could have been made by the person's brain, given different causes acting within the brain.
I fail to see how everything that could happen, does happen has any relevance to free will. If anything, the Many Worlds theory points to Determinism Gone Wild. Not only does one thing happen according to the laws of nature, everything happens.
Assuming the Many Worlds theory of the quantum realm is true. I'm not aware of any empirical evidence that it is. Thus Hawking's conclusion in Episode 3 struck me as poetic and appealing, but not convincing: "The universe you see is the one that gives rise to you out of all possible universes."
A member of the threesome said, "It took a whole universe to make me." OK, granted. The Big Bang can be viewed as the cosmic event that led to the present moment. Another quote from the episode: "We are a product of the universe, but the universe we live in is personal to us."
We all experience the world through our own subjectivity. And the Many Worlds theory takes this farther, since there supposedly are countless other "me's" having subjective experiences in parallel universes. Naturally the only universe I'm aware of is the one I'm in.
It makes sense for Hawking and his collaborators on "Genius" to end Episode 3 on a semi-uplifting note after effectively putting free will on a skewer and roasting it to death. The basic answer he gives to the episode's main question, Why Are We Here?, is that we are here because we're not in an infinity of other parallel universes.
Again, how this relates to free will and choice eludes me. But maybe the universe simply has determined that I'm not supposed to understand this.