Bayesian Brains

Zac tilted his head to one side. “I mean, it’s weird-as-fuck, but I understand what’s happening.”

“Okay, good. Let’s explore why you think this is weird-as-fuck. Remember how we talked about Bayesian rationality earlier? Where the probability of something being true is contingent on two things: how sensible it is based on prior evidence, and how well it fits the new evidence?”

“Yep,” Zac said. “You explained that when you admitted to stealing my gourmet hot chocolate powder.”

“You already knew I was stealing your hot chocolate! I’d literally steal it right in front of you, just for lols.”

“Well, I just wanted to hear you confess and show some remorse.”

“I have zero remorse for my actions.”

“Can you at least say sorry?”

“No,” I said firmly. “I’m not a good liar. Plus, I’ve only ever heard you say sorry to me once in eight long years of me putting up with your shit.”

“I would never apologize to you!” Zac gasped. “My ego would not allow such a thing. When did this happen?”

“Remember we were in Shanghai that time and I booked us a flight to Guangzhou the next day in the early afternoon. And I was like, ‘We need to make sure we leave plenty of time to get to the airport because I have to pack up the apartment in Guangzhou tonight and get myself to Hong Kong first thing tomorrow morning’ and you were like ‘Take a chill pill, Nikki. I have shit to do.’ And then we had to go to the markets, and then we met that Iranian dude who you chatted to, and then you were on a phone call with your factory, and then we had to go pick up a suit from your tailor, and then it was your tailor’s birthday, and I kept telling you we needed to leave, but you were like ‘Nikki, relax,’ and then we found ourselves in the taxi calculating the probability of getting to the airport in a negative amount of time and just as we arrived we watched our plane take off, and you had to pay a ridiculous amount for new flights that evening. And it was, without a doubt, all worth it just to see you turn around and look me in the eye and begrudgingly say ‘I’m sor-’”

“Okay, I get it.”

“Excellent. Now let’s press on.” I gathered up my thoughts again. “Bayesian rationality. You need to realize that your brain is a kind of imperfect Bayesian inference engine. It’s constantly taking in data to model its environment using a Bayesian process. So, for example, why do you like living in Medellin so much?”

Zac smiled to himself. “The lack of strict rules — that’s my kinda place. There are so many opportunities in Colombia! Growth, projects, adventure. Oh! And the weather-”

“Yes! I was hoping you’d say the weather. Why do you like the weather?”

“Well,” Zac said, “it’s the city of eternal spring. Except for a few weeks of rainy season, you get perfect sunshine and blue skies every day. There’s no need to bring a jacket of an evening — you can sit outside for dinner, and walk around without overheating, and have movie nights on the terrace overlooking the mountains and the city.”

“Exactly! So, if every day in Medellin is sunny, sunny, sunny, your brain then predicts that the next day will also be sunny. It has taken in prior information and is subconsciously making a prediction about tomorrow’s weather. That’s why, when I’d wake up in the morning, I’d intuitively assume that it was going to be sunny and could put on a light sundress without checking the weather. But then I also remember that time we were out on your motorbike and got caught in a spontaneous torrential downpour-”

“Oh yeah! That was wild.” Zac chuckled to himself. “Who needs a water theme park when you’ve got a motorbike, rain, and an assorted collection of potholes? I just remember gunning it down the highway, literally flying blind for ten seconds. I was doing my best not to get us both killed, and you were just sitting on the back, having a great time.”

“Yes,” I sighed. “I vividly remember nearly dying that day, but I very much enjoyed the experience. Anyway, my point being, we got caught in the rain because there was a prediction error. There was a gap between what our brains expected to happen and what actually happened. My brain had taken in data and modeled a reality that was sunny every day. It then tailored its actions to that model of reality. And then when it rained, I was caught by surprise because it was unexpected.”

“Okay, yeah, I get it,” Zac said. “So what does this have to do with Schrödinger’s puss-”

“Cat, Zac! Schrödinger’s cat.”

He shrugged. “Have it your way.”

“Well, I just want to point out why it’s perfectly logical that everyone calls quantum physics weird-as-fuck and spooky and mysterious. Since birth, our brains have been trained to model a reality that is objective and mechanical, with linear cause-and-effect. And then people look at this experiment, and they freak out, and their brain starts melting, and they’re all like ‘WTF?!’ and they label it ‘weird’ and ‘mysterious.’ But it actually isn’t weird at all.”

“It isn’t?”

“No! This is what I find funny about physicists. They think quantum physics is so weird, but it’s not! Remember, one of these statements is true: either reality and consciousness are the same thing, or reality and consciousness are not the same thing. If reality and consciousness are the same thing — which is our default position anyway, according to a correct application of the scientific method — then the ‘weirdness’ of the quantum world is exactly what you’d expect.”

“How so?”

“Okay,” I said. “First, let’s talk about our conventional view of the world. Most people intuitively assume that reality and consciousness are separate things. When we look out at the world, all the information entering our senses tells us reality is solid and objective and material, and we are separate from everything else. But then this double-slit-”

“Wink.”

“-experiment is done, and the results are unexpected. They’re counter-intuitive. We would intuitively expect the electrons to travel through the slits like solid marbles, regardless of whether they were being measured — in the same way that I’d intuitively expect it to be sunny tomorrow in Medellin. And when that doesn’t happen, we are shocked. The empirical evidence contradicts our intuitive assumption about the way the world works.

For decades — centuries, even — physicists have been seduced by their senses and duped by the illusion. They come up with their complicated ideas and hypotheses and interpretations, scratching their heads and trying to understand something they’ve intuitively labeled as ‘weird’ without ever stopping to question the most fundamental assumption that underpins all of physics: either reality and consciousness are the same thing, or they’re not the same thing. One of those statements is true.

According to a correct application of the scientific method, the default assumption should be ‘reality and consciousness are the same thing’ because it only assumes the existence of one variable that we already know exists. Any scientist who wants to claim that there is a reality — y — separate to consciousness — x — has a burden of proof on them because they’re adding in an extra unnecessary assumption.

The conventional thinking around this problem really, genuinely, puzzles me. I don’t understand why everyone is putting so much faith in their feelings about the way reality should work, instead of what logic, evidence, and a rational line of inquiry point to. Our consciousness is literally modeling reality according to some kind of imperfect Bayesian process. We know this. This is common sense. This is how we learn and adapt to our environment. Obviously this Bayesian process is imbuing a metric fuckton of cognitive bias in the minds of all the physicists because they still seem to think that reality and consciousness are separate variables. Logic doesn’t give a shit about what you think should be true, so why on earth is everyone placing so much faith in the flimsy intuition produced by their Bayesian brain? Your subjective feelings about the way reality should work are not a valid factor in a logical argument.

So here we are in this situation where, at a high level, the ‘weirdness’ of the quantum world is very easily explained under the assumption that reality and consciousness are the same thing — which is what all the evidence so far supports anyway. It’s not that strange. It’s not that puzzling. It’s only puzzling if you try to manipulate and massage and hammer quantum physics into a format to support your own ill-informed assumption that a material reality exists as a separate variable to consciousness. Because if reality and consciousness are the same thing, then you’d expect that reality would function like a computer game, which is information-theoretic. Here, look at this…”

I pulled my laptop towards me on the bed and opened up my game of Minecraft.

“See my player here?” I said. “Let’s pretend she is an artificial intelligence bot. From her perspective, there is a whole world out there — trees, sky, mountains, other people, animals. Everything appears to have a linear cause-and-effect. See, she can break blocks and run around and pick up things and cut down trees. From her perspective inside the game, she believes reality is objective and material.

But from our higher perspective outside the game, we know that there is no world ‘out there.’ There is just information rendered in a particular sequence to give the illusion that there’s a world ‘out there.’ Until she observes something, that thing doesn’t actually exist in a specific state. It’s in a superposition in the codebase. Anything could happen outside of her awareness, but the moment she observes something, that ‘thing’ needs to manifest in a particular state.”

“Oh, shit,” Zac’s eyes widened. “So if this Minecraft AI bot were to run these double-slit experiments inside her world, she’d be like ‘This is spooky! Why is quantum physics so weird? I can’t explain it!’”

“Yes! Exactly!” I said. “Because her consciousness has modeled a material and mechanical reality, so she intuitively believes that reality should behave that way. But at the deeper level of reality, everything that’s outside of her — the grass, the trees, the animals, the other people — is her. They all emerge as different aspects of the same codebase. It’s all just information. The observer is observing itself from different perspectives. Reality and consciousness are the same thing.”