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Comment by TelmoMenezes | Hacker News Reader

I am aware of this line of reasoning, but it contains a subtle problem: there is no way to measure consciousness. We assume a correlation between consciousness and human-like intelligent behaviour. We assume that we are unconscious when in deep sleep, for example, but we have no way of knowing for sure. It could just be that we are not recording any memories for later reference. Long story short, no, there is no scientific evidence whatsoever that damage to brain will impair an entity's level of consciousness -- only of intelligent behaviour.

It turns out that it is precisely the claim that consciousness emerges from the brain -- given our present state of knowledge -- that is mysticism. The only possible scientific position here is to say "I don't know".

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That's an interesting way of looking at it.

Some problems. Why is there any reason to assume that intelligent behaviour and consciousness aren't the same thing? If a vegetative human with next to no brain function is going to be considered conscious for all intents and purposes according to what you have written above, then you are suggesting that consciousness resides somewhere else, perhaps as an artefact of 'living'.

In my more deeply reflective moments I've sometimes thought that maybe even very simpl chemical reactions, such as the conversion of carbon compounds to carbon dioxide and water, may be a form of consciousness - basically, consciousness exists where there are energy gradients and is thus deeply tied with entropy and thermodynamics.

So, that could be true, but that is different from the meaning of being human, and of having a conscious existence that is rich with relationships with friends, activities and memories, plans etc... Consciousness without memory would not be productive in our present incantations as humans- a conscious being without memory would have no language, no concept of how to act, or why, so if such an entity exists, or exists when we sleep, could you really call it conscious? What wouldn't be observing? What would it be comparing and contrasting its experiences to?

I said before that, for a species of our current level of philosophical and scientific understanding, the idea that consciousness is an emergent property of neuronal activity seems appropriate, even if it isn't complete. It is not true that this is mysticism, because in order to suggest they consciousness doesn't correlate with intelligent behaviour, you are actively claiming things that we don't know and have no proof of in order to suggest that consciousness is something other, and intelligence a subset of.

As a species we generally agree that consciousness is a property possessed by things with neural networks, and the more complex the neural network, corrected for body size, the more advanced the level of consciousness and level of self awareness. So intelligence is basically included in this definition, and although we can't really measure either well, we do know that it is the activity of neurons that leads to one, and despite the oft-pointed out incompleteness of this layer of definitions, it is both supported by available evidence and not so much of a problem, given that these are enormous questions that civilisation shall likely struggle to fully understand for as long as there are humans about to think on it

I commented elsewhere, linking to Integrated information theory[1] but it's relevant here also because you claim theres no way to measure consciousness, but as soon as you accept a formal definition of consciousness like IIT than there is a way to measure it, at least hypothetically. So this is a fallacy preserving the immeasurability of consciousness as a side effect of rejecting any specific formal definition of it as incomplete [1]http://en.wikipedia.org/wiki/Integrated_information_theory

Consciousness cant' define itself? Incompleteness theorem!

If there's no way to measure consciousness, how do you know you have it?

> there is no scientific evidence whatsoever that damage to brain will impair an entity's level of consciousness

There is loads of evidence from studying states that alter the brain.

For example, damage to certain parts of the brain produces hemispatial neglect. The person loses awareness of not just one half of the universe but the concept of that half. This is not consistent with an incorporeal soul, which would continue to make judgements about the full universe albeit with hemispatial blindness.

Then there are dissociative states, as with some migraine auras, where some aspect of self-awareness is lost, leaving the person with the sense that they are watching their own actions in the third person, but with otherwise intact behavior.

There are the dissociative anesthetics like nitrous oxide and ketamine, which create a solipsistic disconnection from the outside world without abolishing self awareness.

The memory function can become disconnected while consciousnes remains, as with some sleep disorders and drugs.

There are delirious states, seen in illness and with some drugs, where the person is conscious but experiencing imagination on the same footing as reality.

The corpus callosum connecting the two halves of the cerebrum can be severed, leaving each side with an independent partially-disconnected consciousness.

In a few sentences you brought more of value to the table than that entire article. I'm all for alternate theories, but the wilder the theory, the more evidence is required. At the very least a thorough look at the existing evidence and how it can be better explained under the banner of the new theory is required.

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