A recent Quora answer I wrote:
A recent Quora answer I wrote:
Someone on Quora asked the following question: What’s the correlation between complexity and consciousness?
Here’s my answer:
Depends on who you ask! Both complexity and consciousness are contentious words, and mean different things to different people.
I’ll build my answer around the idea of complexity, since it’s easier to talk about scientifically (or at least mathematically) than consciousness. Half-joking comments about complexity and consciousness are to be found in italics.
I came across a nice list of measures of complexity, compiled by Seth Lloyd, a researcher from MIT, which I will structure my answer around. [
Lloyd describes measures of complexity as ways to answer three questions we might ask about a system or process:
1. Difficulty of description: Some objects are complex because they are difficult for us to describe. We frequently measure this difficulty in binary digits (bits), and also use concepts likeand Kolmogorov (algorithmic) complexity. I particularly like . It’s a measure of the computational resources required to specify a string of characters. It’s the size of the smallest algorithm that can generate that string of letters or numbers (all of which can be converted into bits). So if you have a string like “121212121212121212121212”, it has a description in English — “12 repeated 12 times” — that is even shorter that the actual string. Not very complex. But the string “asdh41ubmzzsa4431ncjfa34” may have no description shorter than the string itself, so it will have higher Kolmogorov complexity. This measure of complexity can also give us an interesting way to talk about randomness. Loosely speaking, a random process is one whose simulation is harder to accomplish than simply watching the process unfold! is a related idea that also has practical applications. (It seems Kolmogorov complexity is technically uncomputable!)
Consciousness is definitely hard to describe. In fact we seem to be stuck at the description stage at the moment. Describing consciousness is so difficult that bringing in bits and algorithms seem a tad premature. (Though as we shall see, some brave scientists beg to differ.)
2. Difficulty of creation: Some objects and processes are seen as complex because they are really hard to make. Komogorov complexity could show up here too, since simulating a string can be seen both as an act of description (the code itself) and an act of creation (the output of the code). Lloyd lists the following terms that I am not really familiar with: Time Computational Complexity; Space Computational Complexity;; ; and “Crypticity” (!?). In additional to computational difficulty, we might add other costs: energetic, monetary, psychological, social, and ecological. But perhaps then we’d be confusing the complex with the cumbersome? 🙂
Since we haven’t created a consciousness yet, and don’t know how nature accomplished it, perhaps we are forced to say that consciousness really is complex from the perspective of artificial synthesis. But if/when we have made an artificial mind — or settled upon a broad definition of consciousness that includes existing machines — then perhaps we’ll think of consciousness as easy! Maybe it’sWhy pay for what’s free?
3. Degree of organization: Objects and processes that seem intricately structured are also seen as complex. This type of complexity differs strikingly from computational complexity. A string of random noise is extremely complex from an information-theoretic perspective, because it is virtually incompressible — it cannot be condensed into a simple algorithm. A book consisting of totally random characters contains more information, and is therefore more algorithmically complex, that a meaningful text of the same length. But strings of random characters are typically interpreted as totally lacking in structure, and are therefore in a sense very simple. Some measures that Lloyd associates with organizational complexity include:, , and several more, most of which I confess I had never heard of until today. I suspect that characterizing organizational structure is an ongoing research endeavor. In a sense that’s what mathematics is — the study of abstract structure.
Consciousness seems pretty organized, especially if you’re having a good day! But it’s also the framework by which we come to know that organization exists in nature in the first place…so this gets a bit. 🙂
Seth Lloyd ends his list with concepts that are related to complexity, but don’t necessarily have measures. These I think are particularly relevant to consciousness and, to the more prosaic world I work in: neural network modeling.
Consciousness may or may not be self-organized, but it definitely adapts, and it’s occasionally chaotic.
To Lloyd’s very handy list led me also addand . Emergence is an interesting concept which has been falsely accused of being obscurantism. A property is emergent is if is seen in a system, but not in any constituent of the system. For instance, the thermodynamic gas laws emerge out of kinetic theory, but they make no reference to molecules. The laws governing gases show up when there is a large enough number of particles, and when these laws reveal themselves, microscopic details often become irrelevant. But gases are the least interesting substrates for emergence. Condensed matter physicists talk about phenomena like the emergence of , which are excitations in a solid that behave as if they are independent particles, but depend for this independence, paradoxically, on the physics of the whole object. (Emergence is a fascinating subject in its own right, regardless of its relevance to consciousness. Here’s a paper that proposes a neat formalism for talking about emergence: PW Anderson’s classic paper “More is Different” also talks about a related issue: )
Consciousness may well be an emergent process — we rarely say that a single neuron or a chunk of nervous tissue has a mind of its own. Consciousness is a word that is reserved for the whole organism, typically.
So is consciousness complex? Maybe…but not really in measurable ways. We can’t agree on how to describe it, we haven’t created it artificially yet, and we don’t know how it is organized, or how it emerged!
In my personal opinion many of the concepts people associate with consciousness are far outside of the scope of mainstream science. These include, the feeling of what-it-is-like, and , the observation that mental “objects” always seems to be “about” something.
This doesn’t mean I think these aspects of consciousness are meaningless, only that they are scientifically intractable. Other aspects of consciousness, such as awareness, attention, and emotion might also be shrouded in mystery, but I think neuroscience has much to say about them — this is because they have some measurable aspects, and these aspects step out of the shadows during neurological disorders, chemical modulation, and other abnormal states of being.
There are famous neuroscientists who might disagree. Giulio Tononi has come up with something called, which comes with a measure of consciousness he christened phi. Phi is supposed to capture the degree of “integratedness” of a network. I remain quite skeptical of this sort of thing — for now it seems to be a metaphor inspired by information theory, rather than a measurable quantity. I can’t imagine how we will be able to relate it to actual experimental data. Information, contrary to popular perception, is not something intrinsic to physical objects. The amount of information in a signal depends on the device receiving the signal. Right now we have no way of knowing how many “bits” are being transmitted between two neurons, let alone between entire regions of the brain. Information theory is best applied when we already know the nature of the message, the communication channel, and the encoding/decoding process. We have only partially characterized these aspects of neural dynamics. Our experimental data seem far too fuzzy for any precise formal approach. [Information may actually be a concept of very limited use in biology, outside of data fitting. See this excellent paper for more: This sums it up: “if information is in the concrete world, it is causality. If it is abstract, it is in the head.”]
But perhaps this paper will convince me otherwise:. [I very much doubt it though.]
I thought I would write a short answer… but I ended up learning a lot as I added more info.
This opinion is unlikely to be popular among sci-fi fans, but I think the “chance” of mind uploading happening at any time in the future is zero. Or better yet, as a scientist I would assign no number at all to this subjective probability. [Also see the note on probability at the end.]
I think the concept is still incoherent from both philosophical and scientific perspectives.
In brief, these are the problems:
You could of course take the position that clever scientists and engineers will figure it out while the silly philosophers debate semantics. But this I think is based on shaky analogies with other examples of scientific progress. You might justifiably ask “What are the chances of faster-than-light travel?” You could argue that our vehicles keep getting faster, so it’s only a matter of time before we have Star Trek style warp drives. But everything we know about physics says that crossing the speed of light is impossible. So the “chance” in this domain is zero. I think that the idea of uploading minds is even more problematic than faster-than-light travel, because the idea does not have any clear or widely accepted scientific meaning, let alone philosophical meaning. Faster-than-light travel is conceivable at least, but mind uploading may not even pass that test!
I’ll now discuss some of these issues in more detail.
The concept of uploading a mind is based on the assumption that mind and body are separate entities that can in principle exist without each other. There is currently no scientific proof of this idea. There is also no philosophical agreement about what the mind is. Mind-body dualism is actually quite controversial among scientists and philosophers these days.
People (including scientists) who make grand claims about mind uploading generally avoid the philosophical questions. They assume that if we have a good model of brain function, and a way to scan the brain in sufficient detail, then we have all the technology we need.
But this idea is full of unquestioned assumptions. Is the mind identical to a particular structural or dynamic pattern? And if software can emulate this pattern, does it mean that the software has a mind? Even if the program “says” it has a mind, should we believe it? It could be a philosophical zombie that lacks subjective experience.
Underlying the idea of mind/brain uploading is the notion of Multiple Realizability — the idea that minds are processes that can be realized in a variety of substrates. But is this true? It is still unclear what sort of process mind is. There are always properties of a real process that a simulation doesn’t possess. A computer simulation of water can reflect the properties of water (in the simulated ‘world’), but you wouldn’t be able to drink it! 🙂
Even if we had the technology for “perfect” brain scans (though it’s not clear what a “perfect” copy is), we run into another problem: we don’t understand what “uploading” entails. We run into the Ship of Theseus problem. In one variant of this problem/paradox we imagine that Theseus has a ship. He repairs it every once in a while, each time replacing one of the wooden boards. Unbeknownst to him, his rival has been keeping the boards he threw away, and over time he constructed an exact physical replica of Theseus’s ship. Now, which is the real ship of Theseus? His own ship, which is now physically distinct from the one he started with, or the (counterfeit?) copy, which is physically identical to the initial ship? There is no universally accepted answer to this question.
We can now explicitly connect this with the idea of uploading minds. Let’s say the mind is like the original (much repaired) ship of Theseus. Let’s say the computer copy of the brain’s structures and patterns is like the counterfeit ship. For some time there are two copies of the same mind/brain system — the original biological one, and the computer simulation. The very existence of two copies violates a basic notion most people have of the Self — that it must obey a kind of psychophysical unity. The idea that there can be two processes that are both “me” is incoherent (meaning neither wrong nor right). What would that feel like for the person whose mind had been copied?
Suppose in response to this thought experiment you say, “My simulated Self won’t be switched on until after I die, so I don’t have to worry about two Selves — unity is preserved.” In this case another basic notion is violated — continuity. Most people don’t think of the Self as something that can cease to exist and then start existing again. Our biological processes, including neural processes, are always active — even when we’re asleep or in a coma. What reason do we have to assume that when these activities cease, the Self can be recreated?
Let’s go even further: let’s suppose we have a great model of the mind, and a perfect scanner, and we have successfully run a simulated version of your mind on a computer. Does this simulation have a sense of Self? If you ask it, it might say yes. But is this enough? Even currently-existing simulations can be programmed to say “yes” to such questions. How can we be sure that the simulation really has subjective experience? And how can we be sure that it has your subjective experience? We might have just created a zombie simulation that has access to your memories, but cannot feel anything. Or we might have created a fresh new consciousness that isn’t yours at all! How do we know that a mind without your body will feel like you? [See the link on embodied cognition for more on this very interesting topic.]
And — perhaps most importantly — who on earth would be willing to test out the ‘beta versions’ of these techniques? 🙂
Let me end with a verse from William Blake’s poem “The Tyger“.
What the hammer? what the chain?
In what furnace was thy brain?
EDIT: I added this note to deal with some interesting issues to do with “chance” that came up in the Quora comments.
A note on probability and “chance”
Assigning a number to a single unique event such as the discovery of mind-uploading is actually problematic. What exactly does “chance” mean in such contexts? The meaning of probability is still being debated by statisticians, scientists and philosophers. For the purposes of this discussion, there are 2 basic notions of probability:
(1) Subjective degree of belief. We start with a statement A. The probability p(A) = 0 if I don’t believe A, and p(A) = 1 if I believe A. In other words, if your probability p(A) moves from 0 to 1, your subjective doubt decreases. If A is the statement “God exists” then an atheist’s p(A) is equal to 0, and a theist’s p(A) is 1.
(2) Frequency of a type of repeatable event. In this case the probability p(A) is the number of times event A happens, divided by the total number of events. Alternatively, it is the total number of outcomes that correspond to event A, divided by the total number of possible outcomes. For example, suppose statement A is “the die roll results in a 6”. There are 6 possible outcomes of a die roll, and one of them is 6. So p (A) = 1/6. In other words, if you roll an (ideal) die 600 times, you will see the side with 6 dots on it roughly 100 times.
Clearly, if statement A is “Mind uploading will be discovered in the future”, then we cannot use frequentist notions of probability. We do not have access to a large collection of universes from which to count the ones in which mind uploading has been successfully discovered, and then divide that number by the total number of universes. In other words, statement A does not refer to a statistical ensemble — it is a unique event. For frequentists, the probability of a unique event can only be 0 (hasn’t happened) or 1 (happened). And since mind uploading hasn’t happened yet, the frequency-based probability is 0.
So when a person asks about the “chance” of some unique future event, he or she is implicitly asking for a subjective degree of belief in the feasibility of this event. If you force me to answer the question, I’ll say that my subjective degree of belief in the possibility of mind uploading is zero. But I actually prefer not to assign any number, because I actually think the concept of mind uploading is incoherent (as opposed to unfeasible). The concept of its feasibility does not really arise (subjectively), because the idea of mind uploading is almost meaningless to me. Data can be uploaded and downloaded. But is the mind data? I don’t know one way or the other, so how can I believe in some future technology that presupposes that the mind is data?
More on probability theory: