A valley in the Alps

How to measure consciousness

What is consciousness? Is it an all-or-nothing affair? Or are some beings more conscious than others?

Even though we may not know the answers to many of these questions, we have some clues. It seems intuitively obvious that a bacterium is more conscious than a rock but less than a person. This may be wrong, but on the surface it seems plausible. I think I have found a way to show that, indeed, this is the case. What follows is my take on the matter.

There is already a serious attempt at describing and measuring consciousness: I am talking, of course, of Tononi’s famous Integrated Information Theory. My gut feeling -though I have very little more than that- is that Tononi’s theory at least partially describes some of the conditions for consciousness. It also seems obvious to me that highly conscious organisms will have high values of “phi,” Tononi’s measure of consciousness. However, as Scott Aaronson points out in his blog, there may be many systems with a high “phi” but nothing that we could call consciousness.

I think Tononi is missing something, and that something is the rest of the world. That is: when Tononi talks about a conscious system, he only talks about that system, but not its surroundings. But consciousness is not just consciousness: consciousness has to be consciousness of something. Organisms evolved to perceive the world around them and make sense of it in order to survive. Consciousness cannot be understood without this.

I propose that the degree of consciousness of a being is proportional to the correlation between its internal states and the state of the universe. That is: the more sensitive the internal state of a being is to the state of the universe, the more conscious it is.

This will be clearer with an example. Think about a rock: its behaviour is completely determined by its weight, shape and current position. Let’s say this rock is in a valley in the middle of the Alps: the shape of the peak 50 km from it has no bearing whatsoever on the internal structure of the rock. Neither does the colour of the tree 20 m from it, nor the rattle of the wings of a crow in the distance. Only the most immediate vicinity (and hardly so) has an influence on the internal state of the rock. I don’t need to know what is happening around the rock to understand its crystalline structure.

How about a person? Well, this morning I happened to be in that valley, looking at the mountains around me. It turns out that the shape of the peak 50 km from me had a notable influence on my internal state, as it determined the firing of my neurons. So did the rattle of the wings of the crow. Of course, the cow pasturing besides me may have felt similar things. Is it as conscious as I am? Hardly. For example, I have studied physics and know about the Big Bang and inflation. My mental states are, therefore, determined by things that happened billions of years ago and which are completely outside of the realm of what a cow may wonder about. Yesterday I was reading about the history of Rome: this means that events that transpired thousands of kilometres from my current position have a measurable influence on my internal state. I am highly interconnected with the rest of the universe. In fact, I am a more faithful mirror of the cosmos than a cow or a rock. It is safe to say, then, that I am more conscious.

How could we measure this? How can we put a number on the degree of consciousness? I have a couple of ideas, but they are half-baked (I thought of this barely 4 hours ago.) The first is to use a measure from physics called “entanglement entropy,” which measures the degree of entanglement between two systems. A highly conscious system should exhibit a high entanglement entropy between itself and the rest of the universe. Since one could theoretically add entanglement just by adding things to the system, I think that probably entanglement entropy density would be a better candidate, but the idea is the same.

Unfortunately, this would be very hard to calculate for a system such as a human. There may be other measures, based on classical probability theory. For example, I could ask myself how different my mental states would be if I changed a certain chunk of the universe, then measure the degree of correlation. This would certainly be easier, though I would have to find a systematic way of going about it. There may already be some way of measuring this type of correlation that I am not aware of: if so, please leave it in the comments and I will be eternally grateful. It could also be that the measurement is related to Tononi’s “phi,” but adding the extra requirement that the processing links to some entity outside the conscious being.

This is as far as my thoughts go as of now. I am dumping them here in hope of some sort of feedback though, after how long this blog has been in hibernation, I would be surprised to get any. If you’re still there and feel like dropping a line, it would be most welcome.

12 thoughts on “How to measure consciousness

  1. geneticfractals

    Of course you get a reply. I agree with the premise that everything, every “being” has a degree of consciousness. I posture that consciousness as we know it is an outgrowth of intelligence. (though if it turns about to be of a different nature, I won’t be very upset). If you do your thought experiment in reverse, human consciousness with a Consciousness Factor = x, then a cow has x/c_cow and a rock has CF=x/c_rock etc. The CF reduces as the thing or being gets more primitive.

    But a rock isn’t completely without consciousness. In its “rigid” crystalline structure there is the story of the mountain that it came from. The movement of the tectonic plate, the molten rock it came from etc. Its interactions with the world around it and universe it came from. Such a rock isn’t composing poetry but if you were to observe it its own timescale, you see it as highly interactive, smart (making the right moves) etc.

    Following the relative lowering of the Consciousness Factor as the thing simplifies, if you take a limit, you will find a very small value for single atom or even particle. If you follow this all the way back to some beginning, then consciousness is a fundamental property of the universe. I’m not talking about a god but about the least conscious stupidest infinitesimal thing that ever existed. Some so close to nothing that it is nothing yet not nothing.

    Enjoy your walk in the Alps. They are totally inspiring!

    1. David Yerle Post author

      Hi geneticfractals! Haven’t talked in a while, great to hear back from you. I agree with you, the rock should also have some “degree of consciousness,” just much lower than a bacterium or a cow. I think Tononi’s IIT would also give you a similar figure. Even if we only take into account things as they are right now, the crystalline structure does react (though weakly) to a number of events around it, so its entanglement entropy shouldn’t be zero. This also takes me to wonder at the maximum level of consciousness one could achieve, which I guess is if the entanglement entropy with the universe is a maximum. Is there a maximum entanglement entropy per unit volume? What would that look like? Could we create an object with these characteristics?

      1. geneticfractals

        “Could we create an object” that is conscious? I’d like to think so. I can’t say I fully understand entanglement entropy but if I understand it correctly than a infinitely conscious system = fully entangled, is fully in sync. If so, then it’s entanglement density would equate some combined entropy of the two entangled systems.

        Good to see you back. We’ve tried to keep the blogosphere going in your absence. With mitigated success 😉

    1. David Yerle Post author

      Thanks for the input, John! And nice to see you back. Yes, I guess this makes the case for panpsychism, which is weird because I the first time I heard about it I thought it couldn’t possibly be right. Funny how gut feeling work!

  2. bloggingisaresponsibility

    YES, you are back! And yes, like genetic said, of course you’d get a reply.

    Great, thought provoking post as always!

    I’ve wondered about measures of consciousness. I imagine we’d want to measure the degree of change, since a rock would have (tiny) internal changes in response to the mountain due to the photons hitting it, the changes in the weather due to that mountain, etc…

    Detecting how consciousness changes when something is taken away has already been done. Sadly, I can’t recall the name of the study or the book that mentioned them, but they imaged brain activity as people looked at optical illusions — the kind where parts of the picture vanish after the viewer does something. Once the viewer reported that the part of the picture vanished, they observed brain activity and were able to isolate the areas of consciousness responsible for that.

    This is a step, but it isn’t enough. After all, we are relying on verbal reports and assuming they correlate to conscious experience before imaging. After all, most of the brain’s processing (including, I believe external stimuli) is unconscious, yet we’d see plenty of activity in the brain for that. So is it enough to observe internal changes? And this is just the brain; the entire human body could respond to changes, yet we wouldn’t call it consciousness (although the brain would be responsible for those changes), so if we didn’t even know to look for the brain and imaged the body as a whole, would this help us?

    Then there’s the other challenge — maybe this thing is part of a larger system that’s conscious, so that we’ve set our sights too narrowly? Assuming something that has physical integrity (like a rock) is where consciousness resides may be a necessary assumption, but could the totality of rocks, or the rock in proximity to other objects form a higher level consciousness? An example of this question is the Chinese Brain Thought Experiment, but others have asked if nations simply as they stand are conscious, given that one can observe changes within in response to external stimuli (e.g.: declarations of war, the passage of legislation, etc…).

    Just some thoughts 🙂

    1. David Yerle Post author

      Hi BR! So great to hear from you! Sorry I’ve been away for so long. In the last year I’ve been working pretty much non-stop on finishing a novel I started five years ago and which kept lagging and lagging on. Now it’s out of the way, so I guess I’ll be posting more often, but not as often as I used to.
      Good point on measuring the change and how that could work. And then there’s the idea of the time lag: for example, my thought processes this afternoon were not caused (or just in part) but the external stimuli at that moment, but mostly by some others that happened at various times in the past. But maybe the “degree of entanglement” would solve both issues, since it really doesn’t matter when entanglement happens, but whether two systems are. Any two systems in interaction will become partially entangled, so in a complex system like a human entanglement happens all over the place. Maybe we could focus more on a frozen picture of the brain and look at what’s entangled with it in this moment, rather than at how it’s changing. I’m not sure.
      Your second point would be an argument against using the degree of entanglement per unit volume, since one could argue a distributed intelligence would be as conscious as a localised one. My gut says a nation or the Chinese Brain should be at least partially conscious in the sense that they are organisms whose configuration depends greatly on their environment. More upsettingly, with my definition a nation may even be more conscious than a human being, which would be an argument against my definition or at least would mean it requires some tweaking.
      As always, you gave me some food for thought. This is great! Sort of feels like going back to this place you knew full of old friends you haven’t seen in ages. It’s really fantastic to hear from you again.

  3. Tristan

    Such a delight seeing an email that you had posted a new article.

    And along the same veins of measuring consciousness, is the ability to add more consciousness to an existing system.

    As computer science, social media, corporations and organizations, and the like grow increasingly more complex, capable of finding more connections/interactions, and generate more variation, they will become a more conscious entity. Humanity will become increasingly more entangled with each other and the universe as a whole as we learn, grow, and connect.

  4. Fourat

    Marvelous. Stopped me dead in my tracks as I read it. What an idea. Welcome back. Looking forward to reading more posts! 🙂

    However did your project/hypothesis on quantum gravity (if memory serves me correct) go?


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