Comment by visarga
6 days ago
There is a very good explanation here - not what brains do, but what brains MUST do. Can we walk left and right at the same time? Can we drink coffee before brewing it? No. There is a bottleneck, a serial action bottleneck on the body. So the parallel brain activity must serialize on the output channel. It has to, or face ruin. If action is serialized in time by physical necessity, then information processing must also unify before action in order to support it. We must act as one -> we must cognize as one -> or perish. There is no way to allow each limb to do its own thing, or the brain not to decide what comes next in a unified way.
I doubt your conclusion that unified action needs unified mentation. One may take unified action without achieving unity of the contents of the brain. Acting with instantaneous regret if you will, flying by the seat of your pants, etc. The brain seems to be able to let competing subsystems alternate getting expressed in action.
Not all brain activity is unified, I just claim it must unify on the output side - behavior and language.
But this is not a brain or organism only problem. Even a cell must unify in crucial moments such as division and chemotaxis. A cell either divides or not, no mid point. To persist it must unify at some moments in its activity, yet it is a distributed system of many parts.
The core principle here is - what is the unit of selection? the cell survives or not as a whole, the organism also survives or not as a whole, not organ by organ. Selection chooses the mechanisms that are viable.
Idk, I'm pretty good at continuing a conversation while handling the busywork of navigating a cafe. Or even riding my bicycle... The brain is a massively parallel bag of meat. We get some real advantages from focus, but the brain does just fine juggling its many inputs and outputs.
Can you state in plain terms what this actually means?
> There is no way to allow each limb to do its own thing, or the brain not to decide what comes next in a unified way.
This is of course not true. I’ve watched people trip over their own feet because the simultaneously tried to go both left and right. I’ve done it myself.
And this says nothing about consciousness. Most actions are not conscious.
> There is no way to allow each limb to do its own thing
I can pat my head and rub my belly at the same time.
If we're talking about consciousness then yes you can walk left/right at the same time. You can drink coffee before it's brewed.
There is no way to allow each limb to do its own thing
What? Why not?
It's physically possible in terms of limb motion. It's very difficult for most people to actually do, sure; but impossible?
or the brain not to decide what comes next in a unified way
There's the idea that a lot of the brain's "conscious decisions" are actually post-hoc rationalisations of unconscious decisions. If so, there's no reason those decisions have to be unified. Maybe the consciousness of the decision and its outcomes must be unified; maybe that's somehow connected to what consciousness really is. Or maybe not!
I don't think there's enough information to say.