From the abstract: "Since lossy integration would necessitate continuous damage to existing memories, we propose it is more natural to frame consciousness as a lossless integrative process and provide a formalization of this idea using algorithmic information theory. We prove that complete lossless integration requires noncomputable functions. This result implies that if unitary consciousness exists, it cannot be modelled computationally."

Seems to be setting up a straw man only to knock it down. Does anyone believe the brain losslessly integrates information? If not, the conclusion doesn't seem to apply.

They do, for even stranger reasons: " In particular, memory functions must be vastly non-lossy, otherwise retrieving them repeatedly would cause them to gradually decay".

To paraphrase babbage, "I am not able rightly to apprehend the kind of confusion of ideas that could provoke such a statement."

Being lossy does not imply reading is lossy, it could be that writing destroys old information.

How funny, retrieving memory in human brains do expose them to potential decay or alteration.

http://phenomena.nationalgeographic.com/2013/05/20/when-memo...

> Every time we bring back an old memory, we run the risk of changing it. It’s more like opening a document on a computer – the old information enters a surprisingly vulnerable state when it can be edited, overwritten, or even deleted. It takes a while for the memory to become strengthened anew, through a process called reconsolidation. Memories aren’t just written once, but every time we remember them.

The wording is confusing, but I thought perhaps they were assuming that an artificial brain would indeed be lossless and therefore could not be modeled computationally.

It isn't that simple. See... http://en.wikipedia.org/wiki/Hard_problem_of_consciousness

The hard problem has to do with the mere fact of subjective experience. The fact that we experience something rather than nothing.

The various permutations of consciousness that make up the entirety of one's experience of reality and the functional relationship between them can of-course be modelled computationally.

If we can model or compute physical processes then we can model or compute the human brain. Is consciousness beyond physics? I realise that some people think so but personally I find it preposterous.

Meditate and you won't find it preposterous.

Absolutely everything you experience is consciousness. You have never experienced concrete objective reality, you have only ever experienced experiences, which is consciousness.

Every idea you have about concrete objective reality is an idea. Ideas are experiences, which are consciousness.

As much as you think you know what is "real", when does "real" exist? Thoughts of the past only ever arise in the present. Thoughts of the future only ever arise in the present.

Within this present experience, which is when everything has ever occurred, can you find anything that is not an experience?

By that logic, you can't even assume that other humans experience consciousness. You are effectively defining consciousness as your own consciousness alone. By that definition, it follows that consciousness cannot be computed because you wouldn't experience it. I don't think this is the definition most people have in mind though.

"You are effectively defining consciousness as your own consciousness alone."

That is a good point, and it bothered me for some period of time, but there is a way to resolve it.

First, we have to recognize that "your own consciousness" is a dualistic framework that assumes that there is a subject (observer) and object (observed).

If you do not assume experience to be "my experience", but rather experience that simply knows itself, then we can see that all experiences are simply known of themselves. When hearing a sound, there is just the sound. No hearer. When seeing the sight, there is just the sight. No seer. When feeling the sensation, there is just the sensation. No feeler.

Why is it then that the feeling and the seeing seem to be occurring to "me" when they are in actuality simply occurring to themselves? It is because this self-known experiences are highly integrated with each other within this body. I assume that you too are having experiences that are not "happening to you", but are rather self known. So your hearing is just the heard. Your seeing is just the seen. Since "your" seen and "my" seen are not integrated, they appear to be happening "over there" and "over here".

But, due to this lack of integration, I ultimately can not be sure that there are other experiences out there, but it seems like a good pragmatic assumption :-)

> If we can model or compute physical processes [...]

We can't, at least not with Turing machines or with things equivalent to Turing machines. Feynman showed in 1982 [1] that Turing machines suffer exponential slowdowns when trying to simulate quantum physics.

Computing physical processes beyond some special cases (which include many very useful physical processes) will have to wait for advances in quantum computing.

[1] http://www.cs.princeton.edu/courses/archive/fall05/frs119/pa...

As a thought experiment, imagine that the mechanical computer in the following comic is used to create a perfect model of your brain...

http://xkcd.com/505/

At what point does it become conscious ? It doesn't seem to me like it would.

As the comic says, electricity is the same thing as rocks just faster processing.

Basic consciousness remains an unsolved problem in my eyes.

Of couse, if you can model or compute the human brain, then none of us has free will since we are merely chemical reactions and the product of environmental inputs at that point.

I have yet to see a precise definition of "free will" that does not require magic (i.e. humans are not bound by the laws of physics) and somehow captures the intuitive feeling that "we" decide what we do. As far as I'm concerned, free will is an illusion.

There is causality. This present moment is the very leading edge of causality being computed.

When do you make decisions? Do you make them in the past? Do you make them in the future? Past and future do not exist. They are simply memories and fantasies arising in this present moment.

If past and future don't really exist and decisions are made this present moment, is your decision pre-determined or is simply instantly determined, now?

If the future were totally deterministic, it would have already been computed. But, it hasn't yet been computed. We are the computation happening right now, and there is reasonable reason to believe that a multitude of possibilities may collapse into the actuality of this moment.

Note that my claim that free will is an illusion does not imply determinism. When I flip a coin (or do a proper quantum-y experiment) the outcome isn't determined either. That doesn't mean the coin decides mid-flight which side feels more comfortable to land on.

Fair enough. Most arguments to discount free will rely on determinism.

Lets go back to this moment, now. Can you find a present moment in which outcomes are determined? Or, are you left with an infinitely slippery field of experience where outcomes are never fully resolved, but rather constantly morph into a new nowness?

What if you, as the experiencer are not a thing that happened in the past or will happen in the future, but rather are exactly this nowness, this exact unfolding computation. What if you are not the data but the present processing?

So, instead of us being the coin that decides in mid-flight, what if we are the processing/unfolding that is deciding?

Yep it certainly seems crazy in a obvious way.

Is it a joke paper perhaps? Reading it, it seems a bit muddled, almost on purpose. Stating known incorrect statements like the brain is 'lossless'.

Unless it's trying to say, you can create a conscious computer (obvious) but to compute it, it might be impossible?

How is that obvious? You can't presume that the physical world is a component of consciousness.

You believe in stuff beyond the physical world. I do not.

I certainly believe in the possibility of stuff beyond the "physical world," by which I assume you mean the space-time continuum of our universe.

You'd have to be a fool to not be open to that possibility, given that we have no idea what or why anything exists, nor what might exist outside of this universe.

If you look closely, the physical world cannot be found. There is only this present moment. Past and future are memory and fantasy arising in this present moment. The couch that I am sitting on does not exist as a couch, that is a mental label. There is just causality rippling in this present moment.