Because the brain has to continually monitor hundreds of inputs like gravity, pressure, balance, visuals, muscle feedback, etc and integrate them with hundreds of outputs to muscles and coordinate the whole thing which keeps changing, that's walking. All this mushroom does is emit a signal that it was already emitting (ie. It's learned nothing) and the robotocists build a walking system around that which handles all the complexity of walking.

Let me rephrase: what's the difference between a child telling their parent to walk and the conscious part of your brain telling the unconscious part to walk? (BTW, I agree that the mushroom isn't learning anything. My point is just that a child communicating with their parents is not a good analogy.)

The "conscious part of the brain" gets credit for the walking ability, because it taught "the unconscious part" how to walk, by providing repeated and detailed direction in progressively higher abstractions until full bipedal locomotion was a readily-accessible skill.

I'm pretty sure that's not true. I think most people learn to walk long before they become aware of being able to walk.

Most people have rudimentary language ability, including the ability to express preferences, as they learn to walk. The average one-year-old child is plenty aware of the world.

Sure. So? That doesn't mean that the conscious part (such as it is at that point) is teaching the unconscious part. You could actually test this by asking a two-year-old who knows how to walk to teach walking to a one-year-old with rudimentary language skills but who can't walk yet. I'd be very surprised if this intervention speeds up the rate at which the one-year-old learns to walk.

Unless you wire the two-year-old's brain up to the one-year-old's so the two-year-old can stimulate the one-year-old's motor cortex, I don't see how that experiment would test my theory. (Maybe I explained it badly.)

Adults already show the one-year-old how to walk, encourage the one-year-old to crawl and try to stand, and so on – but the adults aren't teaching the one-year-old how to coordinate muscles. That's all the doing of the one-year-old. Some of it's instinctual (as it is in other mammals), and we have some relevant reflexes once you're actually up and standing (assuming you stay within their domain of efficacy), but overall, walking isn't instinctual for humans.

Consider physiotherapy in adults recovering from a nervous system issue. The physiotherapist has to guide the patient through exercises to rebuild motor coordination ability. (Some adults figure this out on their own, invent and practice their own exercises, and breeze through the physiotherapy, but in general physio is long and boring and arduous, because it's very frustrating and doesn't come naturally.) That's the sort of thing infants do on their own volition (with some encouragement from caregivers), but I don't see how it makes sense to say it's not their volition.

Remember the original scenario was "a child telling their parent to walk", so literally using language to communicate a high-level goal to a "lower-level" system.

I don't have kids so I have no direct experience with this, but I'm pretty sure that parent's don't actually instruct their kids how to walk. Kids figure it out mostly on their own. Parents might accelerate the process by giving guidance and encouragement, but even that probably is just another feedback channel. The heavy lifting is all in the kid's brain.

Contrast that with learning how to play chess. The latter is something that a higher level system really can teach to a lower-level one. Really good chess players eventually develop sub-conscious pattern-matching abilities that are very much like a motor skill, but before that happens a person first has to learn to play chess using slower deliberative methods, and they learn that through language. Other good examples are learning to drive, or fly an airplane, write code. But walking really is different. There's a reason that walking is not taught in preschool. (Physiotherapy is different. And as you yourself point out, some people figure that out on their own too.)

>Because the brain has to continually monitor hundreds of inputs like gravity

Human brains cannot monitor gravity. We're actually very bad at it.

Also you're failing to understand the scaling involved here, so to speak. I'm actually really not interested in trying to explain this if you can't be bothered with spending a few minutes on how nervous systems work.

They're obviously referring to the vestibular system. If that system is bad, that only makes the brain's job harder, not easier.