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> Even if we accept the most fringe, anthropocentric theories like Penrose & Hammerhoff’s quantum tubules, that’s just a neural network with fancy weights.

First, while it is a fringe idea with little backing it, it's far from the most fringe.

Secondly, it is not at all known that animal brains are accurately modeled as an ANN, any more so than any other Turing-compatible system can be modeled as an ANN. Biological neurons are themselves small computers, like all living cells in general, with not fully understood capabilities. The way biological neurons are connected is far more complex than a weight in an ANN. And I'm not talking about fantasy quantum effects in microtubules, I'm talking about well-established biology, with many kinds of synapses, some of which are "multicast" in a spatially distinct area instead of connected to specific neurons. And about the non-neuronal glands which are known to change neuron behavior and so on.

How critical any of these differences are to cognition is anyone's guess at this time. But dismissing them and reducing the brain to a bigger NN is not wise.


There's a lot of other interesting biology besides propagation of electrical signals. Examples include: 1/ Transport of mRNAs (in specialized vesicle structures!) between neurons. 2/ Activation and integration of retrotransposons during brain development (which I have long hypothesized acts as a sort of randomization function for the neural field). 3/ Transport of proteins between and within neurons. This isn't just adventitious movement, either - neurons have a specialized intracellular transport system that allows them to deliver proteins to faraway locations (think >1 meters).
It is my understanding that Penrose doesn’t claim that brains are needed for cognition, just that brains are needed for a somewhat nebulous „conscious experience“, which need not have any observable effects. I think that it’s fairly uncontroversial that a machine can produce behavior that is indistinguishable from human intelligence over some finite observation time. The Chinese room speaks Chinese, even if it lacks understanding for some definitions of the term.
But conscious experience does produce observable effects.

For that not to be the case, you'd have to take the position that humans experience consciousness and they talk about consciousness but that there is no causal link between the two! It's just a coincidence that the things you find yourself saying about consciousness line up with your internal experience?

https://www.lesswrong.com/posts/fdEWWr8St59bXLbQr/zombies-zo...

That philosophers talk about p-zombies seems like evidence to me that at least some of them don't believe that consciousness needs to have observable effects that can't be explained without consciousness. I don't say that I believe that too. I don't believe that there is anything particularly special about brains.
The p-zombie argument is the best-known of a group of conceivability arguments, which ultimately depend on the notion that if a proposition is conceivably true, then there is a metaphysically possible world in which it is true. Skeptics suppose that this is just a complicated way of equivocating over what 'conceivable' means, and even David Chalmers, the philosopher who has done the most to bring the p-zombie argument to wide attention, acknowledges that it depends on the assumption of what he calls 'perfect conceivability', which is tantamount to irrefutable knowledge.

To deal with the awkwardly apparent fact that consciousness certainly seems to have physical effects, zombiephiles challenge the notion that physics is causally closed, so that it is conceivable that something non-physical can cause physical effects. Their approach is to say that the causal closure of physics is not provable, but at this point, the argument has become a lexicographical one, about the definition of the words 'physics' and 'physical' (if one insists that 'physical' does not refer to a causally-closed concept, then we still need a word for the causal closure within which the physical is embedded - but that's just what a lot of people take 'physical' to mean in the first place.) None of the anti-physicalists have been able, so far, to shed any light on how the mind is causally effective in the physical world.

You might be interested in the late Daniel Dennett's "The Unimagined Preposterousness of Zombies": https://dl.tufts.edu/concern/pdfs/6m312182x

Like what is magic - it turns out to be the ability to go from interior thoughts to stuff happening in the shared world - physics is just the mechanism of the particular magical system we have.
If brain isn't more special than Chinese room, then brain understands Chinese no better than Chinese room?
The brain is faster than the Chinese room, but other than that, yes, that's the so-called systems reply; Searle's response to it (have the person in the room memorize the instruction book) is beside the point, as you can teach people to perform all sorts of algorithms without them needing to understand the result.

As many people have pointed out, Searle's argument begs the question by tacitly assuming that if anything about the room understands Chinese, it can only be the person within it.

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