Hi Helder!

Good question about why I'm using discrete and finite systems formalize causal emergence, rather than analog concepts (like feedback, etc). The first reason is that this allows supervening scales to be easily defined and modeled. For instance, one can generate the full space {S} of possible supervening descriptions of any particular system, and then search across that space, as we did in Hoel et al. (2013) "Quantifying causal emergence." Another reason is that information theory, such as mutual information is most often represented as between two finite and discrete variables. A third is that the causal calculus of Pearl is also often represented in terms of Markov chains. So showing how these all can be synthesized is much more direct in these types of systems (applicable to things like cellular automata, etc).

But this doesn't mean linearity / nonlinearity and related concepts doesn't come into play, it just wasn't addressed in this essay. See Hoel (2016) "When the map is better than the territory" of a discussion on how symmetry breaking is critical for causal emergence.

Thanks so much for reading!

Erik P Hoel

Dear Erik,

Great Essay! The way you address physical entities, called agents, seem to be related to what I called operators, as I defined in my essay:

http://fqxi.org/community/forum/topic/2846

Both of them are defined with autopoesis functions in mind, though I isolate a specific type of reaction which I believed gave birth to life on earth, which are benchmarks where chemical clocks regulate themselves. They'd have the whole oceans for them and they'd evolve at first by struggling to be stable against perturbation.

I'd like to know your view, so that I can build a positive feedback.

    Hi Erik

    Thanks for that.

    Well I have been persuaded that it may be better to talk about causation as horizontal, emergence as bottom up, and realisation as top-down. But partly its to do with the three different (interelated) aspects of emergence: evolutionary, developmental, and functional. The first two are diachronic and the last synchronic. It is in the third case that the issue of supervenience arises.

    However what is important is still the issue that it is the higher levels that decide what will be done and the lower levels that carry out the work, which your group have discussed in terms of higher levels having greater causal powers than lower levels. That is a key aspect.

    Best regards

    George

    (they log you out after a while I think and you have to log in again)

    Dear Erik,

    Excellent essay, I liked it very much, both how it is written, and the ideas. The result that open emergent systems can be able to win the fight with the underlying, more fundamental level which apparently gives us all the reasons to think it will make them very unstable, seems to me a breakthrough, a long awaited answer to an important question. Congratulations! If I understand well, this solves the tension between fundamental lower levels and emergent levels without the latter having to break causality of the possible microstates of the former, by using loops that include the environment. A similar tension, but not necessarily related to agents with goals, happens between the classical level and the quantum level, where the quantum level determines the classical level but at the same time it is constrained by it. Unfortunately, in this case it seems there is no way to solve the tension without the quantum level giving up in the face of the classical level, by the wavefunction collapse (I think this has some problems, e.g. it breaks the conservation laws, but there is another way, I explained it in this older essay).

    Best regards,

    Cristi Stoica

    The Tablet of the Metalaw

      Dear Erik,

      I really enjoyed part 4. "Teleology as breaks in the internal causal chain" so thank you.

      Is it essentially an account of how causes can cause us to think there is purpose is causes? If our brain was in a vat we wouldnt have teleology, much like we wouldnt know stuff far away from the vat?

      Thanks Jack

      http://fqxi.org/community/forum/topic/2722

        Thanks so much Cristi - so glad you found it enjoyable. You immediately hit on one of most interesting questions of this research: how do we related the causal work of the microstates to that of the macrostates. We don't want to multiply entities beyond necessity and have things be overdetermined. There's a few different options - you're right that when it comes to teleological causation (as outlined here) there's less conflict. Just in general causal overfittig and underfitting are nice schemas that outline how it may be non-overlapping in some cases. I give two further options in the endnotes: supercedence (macro entirely constrains or controls micro) or layering (macro contributes what it does above and beyond the micro but micro also contributes). Both of these are viable positions: we argued supersedence in the first paper on causal emergence (Hoel et al 2013) and I argued layering in the second (Hoel 2016).

        I just read and greatly enjoyed your own essay - great explanation of how to "zoom" in and out of the different scales and what that means in terms of coarse-grains and thermodynamics. At some point the research on causal emergence should be connected to thermodynamics, given exactly what you're talking about.

        Thanks again!

        Erik P Hoel

        Thanks Daniel, I appreciate it.

        I made a comment on your essay so we can have the discussion there - thanks for linking!

        Erik P Hoel

        Dr. Hoel,

        You have composed a very impressive discussion about the workings of agents and the role they play in pursuing goals and intentions. Your hierarchy of science, in some ways, parallels the line of thought I chose to develop in my essay.

        One thing that I seem to miss (although it may be there and I am just not aware of it) is that, your central theme is 'How agents causally emerge from their underlying microphysics,' but you never really address the theme. You never say how they emerge; at least, I did not see it in the essay. In fact, in your abstract you state,

        "I argue that agents, with their associated intentions and goal-oriented behavior, can actually causally emerge from their underlying microscopic physics,"

        but in Section 5 of your essay you say,

        "Ultimately, this means that attempting to describe an agent down at the level of atoms will always be a failure of causal model fitting."

        The two statements appear contradictory to me. I will concede that I am not knowledgeable in this field, and the consistency may either escape me or be beyond me.

        Can you say in a brief summary paragraph how agents causally emerge from their underlying microphysics?

        Regards,

        Bill Stubbs.

          Dear Eric,

          Beautiful essay, congratulations.

          Your agents emerge from the quantum state, my reality (including agents) emerge from the state below the quantum scale, behind the wall of Planck.

          So also the the quantum cale is an emergent phenomenon.

          I wonder what your valued thoughts are of my contribution "The Purpose of Life

          best regards

          Wilhelmus de Wilde

            Thanks very much Jack.

            To answer your question: I wouldn't say that the brain in a vat has no teleology, I'd say it does, it's just that its causal relationships don't locally supervene (you couldn't find them no matter how hard you looked). So it's precisely by comparing brains in vats to brains in bodies that you see the causal structure of the brain is actually much more rich than it first appears in isolation. It's those non-locally supervening causal relationships that are teleological (or, if you want to hedge, merely appear teleological)

            Will check out your essay post-haste,

            All the best,

            Erik P Hoel

            Thanks for the read Bill! I'm not sure why those two things would be contradictory in your mind. But I suspect it might have something to do with how I'm using the word "emergence" and what you associate with it.

            It's worth noting that emergence can be used semantically in two ways (above you can see George Ellis's comment about this as well). You can use it to say "the patterns emerged from the simple chemical interaction." In this manner it usually means getting something complex from something very simple: it's fundamentally historical. This isn't the usage herein.

            There is another way to talk about emergence. For instance, if I had a bunch of NOR logic gates, and I hooked them up to make a complicated circuit that enacts many different kinds of logic functions (like ORs and ANDs and NOTs), you would say that the circuit and other logic functions "emerged" from the underlying NOR gates. This is the way I use emergence in the paper.

            Since you asked, here's a brief summary of causal emergence (takes in deep breath): the causal structure of systems can be treated mathematically as a communication channel over which states are sent over time (much like sending messages), and it turns out that describing/observing/intervening upon the system in terms of a higher scale can actually make the channel transmit more information because these higher-scale descriptions are a form of channel coding. Whoof!

            Thanks very much Wilhelmus. I didn't explore anything down at the quantum level for my own essay. To me it seems that relying on quantum effects to explain agents is like trying to solve a single mystery by combining two mysteries, which generally just makes everything even more mysterious, but I'm eager to read your essay and find out. I will check it out there.

            All the best,

            Erik P Hoel

            Thanks George. I definitely agree that emergence can be taken in a historical sense (evolution, development, complexity from simplicity) and a level sense (function, scale, causation). It's only in the latter sense that it involves issues of supervenience.

            I had a question about your comment: what exactly do you mean by "it is the higher levels that decide what will be done and the lower levels that carry out the work?" Can you explain that a bit more? It may illuminate some of our differences in approach. Because if the lower levels are carrying out the causal work in the system, didn't the lower levels really make that previous higher level decision?

            What we are saying is in a sense the opposite of this: causal emergence is only when a macroscale outstrips the microscale in terms of information and causal work, so proving that causal emergence occurs involves directly assessing the causal structure at both the microscale and the macroscale and comparing the two. I think it's really helpful to use simple but well-defined systems like Markov chains for this exact reason: you can derive all the possible supervening scales along with the full causal structure.

            All the best,

            Erik P Hoel

            Dear Erik,

            Thank you for your well written and detailed essay. I thoroughly enjoyed reading it. As others have commented, I particularly agree with your analysis on emergence across multiple levels of scale and particularly liked the way you tied them all together in your conclusion, "purposeless microscale descriptions are like a low dimensional slice of a high dimensional object". I voted on your essay a few days ago, but just thought I'd give you a more detailed reply on how much I enjoyed it.

            Regards,

            Robert

              Thanks so much Robert! Very nice to hear it. Just finished your essay - I greatly enjoyed your breakdown of Maxwell's Demon, and it got me thinking about the long history of cases of trying to get something from nothing. In Maxwell's case, it's a violation of the 2nd law. I think for a long time people have thought of emergence in that way - it's almost like getting something from nothing, because how could you possibly gain any information or causal work going up to a macroscale? It seems like squeezing something from nothing, and I think it is this that's the intuitive force behind the "exclusion argument." But there's a few cases where some people have figured out how to squeeze something from nothing (metaphorically, obviously). One of those is Claude Shannon's noisy-channel theorem. At first it really seems a really noisy channel can only transmit very low amounts of information. Then Shannon showed that through channel coding the information can be radically increased - without altering the channel! By saying that causal emergence comes from treating a system's causal structure as a channel, and that macroscales are encodings for the channel, I'm piggy-backing on Shannon's "something from nothing" proof. So causal emergence is kind of like getting something something from nothing (without altering the system).

              Anyways, just wanted to let you know your essay inspired me to think about it with a new analogy.

              Thanks so much!

              Erik P Hoel

              Dear Erik Hoel,

              just rated your essay and gave it a high score. Your concept of causal emergence is intriguing and you should further investigate it. It also poses interesting teleological questions.

              Best wishes,

              Stefan Weckbach

                Thanks so much Stefan, I'm so glad you found it intriguing. I definitely plan on investigating it further (when I find the time!). In terms of teleology, I think you're right. However, I'm always wary of those kinds of words, so my own personal stance is to try to explain what looks like teleology (apparent teleology) without coming to overt metaphysical conclusions.

                Thanks so much for reading and rating!

                Erik P Hoel

                Hi Eric P. Hoel,

                I offer a complementary suggestion. In addition to pushing along trying to elaborate on the usual assumptions, you might also pause and see what challenges those underlying assumptions. I have an essay that introduces some of the challenges facing the scientific vision of life,

                http://fqxi.org/community/forum/topic/2783

                If nothing else it might introduce some additional puzzles to mull over.

                I hope things are going well for you.

                Ted Christopher

                  Thanks so much George! Actually, Larry was on my PhD thesis committee at UW-Madison. He does excellent work.

                  There's a handful of analytic philosophers who have thought about these issues, starting with Yablo. There's also List and Menzies, as well as Shapiro and Sober. All these people do incredible work and have all touched on issues related to causal emergence at some point or another, although most are focused more on problems of mental causation. None have, as far as I know, argued explicitly for the theory laid out here and elsewhere.

                  One constant problem that I have with this research is the consequence of framing it in terms of the exclusion problem. It's a good way to frame it because it hammers the problem home, but it's a bad way because the exclusion argument is a well-known philosophical issue and people then immediately assume this is a philosophical solution to a philosophical problem. But as I indicate in the essay, I'm using the exclusion argument as a stand-in for a more general issue concerning causal structure, information, and model choice.

                  Ultimately, I think this requires a scientific (or mathematical) theory, composed of: A) formalizing supervenience as changes in scale or as highlighting only subsets of the system's state-space; B) some sensitive measure of causation and/or information (I've used information theory and Pearl's causal calculus) that can handle things like noise, is proven to be related to various important causal properties, doesn't give nonsensical answers for simple scenarios, etc; C) actually checking and proving that B can be higher across various scales made with A; D) explaining why it's theoretically even possible that the macro can beat the micro; E) hopefully some applications.

                  Originally we argued in 2013 for the D that macroscales reduce the noise in the system (over both the past and the future), and that's how causal emergence occurs. I think there's another interesting way of framing it, which is that macroscales can be thought of as codes (as I argue here and elsewhere), and the macro can beat the micro because of Shannon's noisy-channel coding theorem. Hopefully both these explanations help with E: actual applications.