Agent Above, Atom Below: How agents causally emerge from their underlying microphysics by Erik P Hoel

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

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

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

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.

Hi Ted - thanks so much for stopping by. I strongly agree that we all make assumptions.

I checked out your essay and was very glad to see you mention Rafael Yuste - he's my principal investigator here at Columbia University. I did want to say that, while I disagree with some of your examples seriously challenging contemporary neuroscience, I absolutely agree with you that little attention has been paid in neuroscience to the consequences of hydrocephalus. IF it's true that people are operating normally but have drastically reduced gray matter (such as 10 to 20%) we're going to need to drastically rethink some things. However, if I remember correctly recent research has questioned these numbers.

http://blogs.discovermagazine.com/neuroskeptic/2015/07/26/is-your-brain-really-necessary-revisited/#.WMVsVRLyuRs

Thanks so much for reading!

Erik P Hoel

Thanks so much Joe - highly appreciate it. Although I wouldn't say any of this is "uncontroversial"! Try getting funding for it hahaha.

I just finished your essay, which I enjoyed, particularly your writing. There's lots of stuff going on in there but just wanted to mention the relationship to my own essay here, which is your segment on higher-level explanations. You say: "In this way, we compress our explanations of phenomena, with the useful result that they can be communicated and shared with fewer bits, thus requiring less work to understand."

I completely agree - this is totally necessary for human communication, or something like science where we communicate facts or data to one another. What I argue in my essay is that there's another possibility for an information theory metaphor beyond just compression for these types of cases: coding. So higher-level explanations aren't always *merely* compressions, sometimes they are also codes; in addition to being compressed, they also error-correct, meaning they can have in theory more information than whatever underlies them.

Thanks for commenting, and I enjoyed your essay,

Erik P Hoel