This puts me in mind of a 1991 essay, in which the philosopher David Stove bemoans our lack of an ontology of the disorders of intellectual philosophical thought. I would be very interested in how you would put together such an ontology.
So Alice lost her job and her insurance and she broke up with Bob which now keeps him inside all day and away from making big plays in commodities. I know it's a vast oversimplification, but the aliens should just materialize universal healthcare and give Bob a new girlfriend. The gallon of prevention that's worth a barrel of cure.
"SAM-e and tetrahydrobiopterin are cofactors for the enzymes tryptophan hydroxylase and tyrosine hydroxylase, which change the amino acids tryptophan and tyrosine into serotonin and dopamine, respectively. And serotonin and dopamine are known to be heavily involved in mood and energy level."
So is this why I sometimes get intense cravings for cheese? As in "I really need to eat some cheddar NOW"? Tyrosine in cheese -> dopamine?
In writing about complex adaptive systems (CAS) we fall into a couple attractor states - either they're still tractable because of the inherent predictability of *some* macro patterns, or they're so complicated because of the number of moving parts that you're shooting in the dark. And yet, despite the billions of variables that affect each part of the economy, we do tend to repeat certain patterns. Even if inadequate that still has some explanatory power.
My contention is that to get to a dynamical understanding, simulations are criminally underused as explanatory vehicles, especially in business/ economic settings (medicine too, though I don't know enough here). We'd need them to help us figure out the right level of abstraction to understand these attractors and the overall shape. (I explored this recently again (https://www.strangeloopcanon.com/p/simulating-understanding). It remains the biggest annoyance I've had against economics since grad school. I want to see the "biochemical pathways" flow diagram equivalent for money, so we can run scenarios and hone assumptions. They'll help us get a better understanding of the strange attractors within the system, while analytical/ predictive models tend to focus more on getting to an answer, which fails in cases of CAS. (This might be a false dichotomy.)
The mind seems a far more complex system than the economy in this instance, and I wonder how you'd even go about the problem of trying to create/ simulate something to get an understanding here.
Homocysteine, huh? Interesting, Sarah was talking about that just the other day on Twitter in the context of mortality rather than depression, and how it's possible that supplementing folate to reduce could be a good idea just in general (but how nobody's done a proper study of this): https://twitter.com/s_r_constantin/status/1356643626785378304
One possibly overly-pedantic query... Where it says, "I think the mind is at least this complicated," surely the mind can't be anywhere near as complicated as the global economy, given that billions of minds are themselves part of the economy?
These are nice, but I think it's a mistake to call them ontologies. They are models which, as you point out, capture a few salient points, but not the whole shtick. I think "ontology" in information science is best used to describe the underlying framework of a humanly-created system, where it can, in theory, be complete and even offer guidelines for further development. But "ontology" is too highfalutin a term for an approximate model of a large and complicated system that we have encountered from the outside and continue to study, many of whose fundamental inner details are unknown and will be for a long time, maybe forever. Using the term "ontology" gives the models more credence than they deserve, since an ontology is supposed to embody the axiomatic basis of the system is associated with, and those are unknown.
Thank you for allowing me to carp on the use of the term. Except for that, I liked your models and the point you are making.
Why wouldn't the attractor states make the taxometrics show a taxa, instead of a trait? Shouldn't the attractor states create multiple modes at the attractors?
Back in the taxometrics post, you had an example of an obvious taxa, humans vs bunnies. But if you included all the species along a continuous traversal through the evolutionary tree from humans to bunnies (i.e. back from humans to our common ancestor, then forward to bunnies), you'd have a smooth curve from human to bunny (smooth i.e. continuous, but not monotonic). Unless I've misunderstood taxometrics, I would imagine that including all those species would cause the statistics to lose the distinction of humans and bunnies as separate taxa, and instead to just conclude they were various parts of a rather large and skewed distribution.
The dynamic system, in this case, would be the environmental selection pressures that evolved the common ancestor towards humans and towards rabbits. It has the attractor states of human, and rabbit, which we can now statistically differentiate into separate taxa. If depression really does have attractor states that we can think of as "has depression" and "doesn't have depression", shouldn't that show up in the taxometrics, just like humans and rabbits do?
This was a delight to read, and felt very natural to me. I've had similar thoughts and discussions about my own mental health, and my experiences with meditation. It also reminds me of everything I've read on SSC and elsewhere describing the mind in terms of a potential energy landscape.
Mostly, though, it reminded me of a recent discussion I had with a coworker about Zvi's lesswrong covid post where they (he?) used the phrase "pretend to pretend to try to try." Her reaction was, "I love that there's a forum out there with an audience that reads that sentence and nods along like it's a perfectly normal thing to say."
Thanks for creating a space where this kind of discussion is a perfectly normal thing to have.
if psychiatrists weren’t aware that some people have persistent depressive symptoms that occasionally get more severe until “double depression” came into the lexicon we are all fucked
Scott is slightly incorrect saying, “An enzyme in your body called MTHFR changes vitamin B9 into the active form l-methylfolate.” In reality, MTHFR changes the intermediate called methylenetetrahydrofolate (a form of folate three metabolic steps downstream from vitamin B9/folic acid) into l-methylfolate.
Why people are paying so much attention to MTHFR when any of the multiple folate cycle enzymes can go wrong? That is because of the so called genetic polymorphism 677C>T or, systematically, rs1801133, which in its homozygous form is present in 12% of Europeans. Homozygous rs1801133 (TT) results in a lower activity MTHFR enzyme (60% of normal activity).
Despite the hype surrounding companies like Genetic Genie, a very simple routine test any doctor (including Scott) can prescribe will tell you all you need to know about the state of your folate system. The test is called plasma total homocysteine, and it is very sensitive to the disruptions of folate metabolism. For example, a person with normal genotype has homocysteine level at 6-7 microM, but a person with rs1801133 (TT) has homocysteine at 10-11 microM. If you treat such a person with with 4 mg of folic acid per day their homocysteine goes down to 7 microM (see figure 3 in MTHFR 677C>T genotype is associated with folate and homocysteine concentrations in a large, population-based, double-blind trial of folic acid supplementation. https://pubmed.ncbi.nlm.nih.gov/21508090/ )
"Some mental disorders are pure traits without much dynamism – I think personality disorders, ADHD, and autism fall into this category." Our seven-year old son has been diagnosed with combined type ADHD, ODD and "mild ASD" (exact words the paediatrician used). From my perspective, there is heaps of dynamism in his symptoms. Right now he is in a good phase, the school tells us he is following the rules, doing the work, even having positive social interactions with other students (he is in a mainstream classroom, not special education). But he has also had his bad phases. Last year, there were weeks when the school called us almost every day to come pick him up early because he has been physically violent against the school staff, and the school was trying to encourage us to pull him out of mainstream and send him to special education instead. (His private Catholic school only has mainstream classes, to go to special education we'd have to enrol him in another school.) There have been periods when I haven't been able to work because I've had to remove him from the home to stop him from physically attacking his mother. But, none of that right now, we are hoping and praying the current good phase lasts, yet we've had good phases that didn't last before. Is that anecdotal evidence against the idea that ADHD and autism are "pure traits without much dynamism"?
Completely foreign and exotic aliens which have no corresponding concepts for "War" and "Money", but can perform sentiment analysis to figure out likes/dislikes from facial expressions? They might not even have faces!
I'm just gonna add a little to the dynamical system and attractors perspective - sometimes a dynamical system has attractors which are not points in phase-space (ie, the multidimensional space of possible states of the system) but rather closed lines (limit cycles). This would mean that the system travels along those lines in a periodic way, and any other orbit in phase space eventually reaches these closed lines. A physical example of this is a mass on a spring with friction that sometimes slows it down and other times speeds it up (van der Pol oscillator).
Do you think this could be a good way to understand disorders which have periodic behavior? Say, is bipolar manic and depressive episodes better understood as "external shocks move the system between stable points", or "the internal dynamics of the system moves it along a periodic trajectory between two extremes"?
Tangent - "But also, the refinery workers might strike in sympathy with the truckers" is a problem that a robust system of social castes solves! If refining and transportation are done by two separate tribes who don't interact socially, don't intermarry, and don't try to horn in on each other's economic domains, then the odds of one tribe paying a cost to show sympathy to the other at the same time that that other tribe is purposefully making things difficult for the first one are essentially nil.
I wonder if a dice roll is a dynamic system with 6 attractor states? It seems like there is some graph that maps a dice leaving the player's hand to its resting state on one face, but the graph is so large that we can't understand it as a system and so think of it as random.
I don't mean to be cynical. It's more important to understand the economy and our mental health than it is to understand which way a dice will fall. Maybe it's even more important to understand just how hard that endeavour is and remind ourselves that anyone who is too confident in their interventions is (at best) a benevolent alien.
“large stimulus packages can sometimes shift the system from recession to normal growth”
To economists out there: is there an example of this actually happening? I know the Great Depression is the era most associated with Keynesian economics, but my understanding is that the increase in taxes (starting under Hoover) made policy not all that Keynesian, and it lasted a long time (even having another recession prior to full recovery).
I'm attaching a celebrated paper which talks about the neuroscience of memory retrieval. It also takes the dynamical systems approach in order to explain how we retrieve memories in our brain. The strength of the paper lies in the fact that it does not make strong assumptions about the brain, and most parameters can be "random". https://www.pnas.org/content/79/8/2554
As an English computer scientist, I was confused both by your use of "gas" to mean "petrol" (I assumed by "gas lines" you meant "pipes for natural gas", not "petrol queues") and your use of "i" and "j" for boolean variables rather than indices.
Just wanted to note that Scott's drawings may be slightly misleading. Critical slowing down is a feature that appears only when the system is going from one macro state to the other (the attractors in Scott's language, although the phenomena occurs in non dynamical systems too), but not in the vicinity of the basin of attraction, so no slowing down near an attractor, even though the drawing might suggest that due to the ground being level there.
It's also funny that the link toward an example of critical slowing down in the global economy is an article claiming there is no evidence for it, which seems to conform to a brief internet search on the terms.
On the very misleading side is calling something fractally complicated due to having causes that have causes,etc. The defining feature of a fractal is self-similarity, so that you do not have to know the underlying cause, everything you need to know is at whichever scale you're looking at and you can understand this scale while completely oblivious to finer details (which are just more of the same).
I'm happy that Scott is back and double happy he is posting very regularly, but throughout the first parts I felt being constantly threatened with math and links to peer-review until I stopped to review some things.
As an expert in dynamical systems, I like this way of looking at the world. Most things are dynamical, and have many variables. A dynamical model of the brain would probably have to contain as many variables as there are neurons. That being said, a surprisingly large number of complicated things behave as if they only have a low number of variables. For example, the transition to turbulence can (usually) be well understood using ideas of chaos theory with a few variables. These sorts of reductions require some sort of continuity or dissipation, which are lacking in the brain or the economy.
I want to correct one error: the opening example has only one dynamical variable. The system can be written in one line, using the sign function (which is +1 if the input is positive and -1 if the input is negative - and for this example, we also want sgn(0) = +1).
h(t+1) = h(t) + sgn( h(t) - 75 )
If it did have more than one dynamical variable, you wouldn't have been able to understand what it does using a one dimensional picture. The picture would be more accurate as a tent, with straight lines going up to a point above 75.
On a tangential note I suffer from atypical depression, though it's likely that my attractors are shallow and I'm moving among those faster than classic MDD (I suspect this being linked to my Delayed Sleep Phase Syndrome messing up the circadian rhytm). My diagnosis could also be incorrect since it's more similar to cyclothymia
This is an interesting and illuminative post. I wonder though about the overly exclusive physiological perspective. I agree the physiological complexity is staggering but there seem to be 2 additional areas left out though you do refer to them obliquely.
The feedback loops created by the external environment and the recursive element of the mind whether conscious or unconscious. Your distinction that the difference between sadness and depression might be that depression is a "stable" attractor state is one I'm not sure I agree with. It could be that there is some variable susceptibility but could it not be the feedback between all 3 systems that deepens the state so that it's difficult to emerge from it without help. If that was true it would perhaps explain why there is no substantive difference between sadness and depression at the outset. I am extending the inference of course that duration is the defining difference, as suggested by taxometrics, and that it's the complex dynamic feedback loops that deepens and creates your attractor state?
Is it also possible for the attractor states to evolve over time so they change in their shape and number, or are they genetically predetermined?
Nice article.
You've done it again Scott. Bookmarked.
Just wanted to mention that this article has not appeared in my RSS feed as of this comment. All the other articles have. Maybe it's just me.
This puts me in mind of a 1991 essay, in which the philosopher David Stove bemoans our lack of an ontology of the disorders of intellectual philosophical thought. I would be very interested in how you would put together such an ontology.
https://web.maths.unsw.edu.au/~jim/wrongthoughts.html
So Alice lost her job and her insurance and she broke up with Bob which now keeps him inside all day and away from making big plays in commodities. I know it's a vast oversimplification, but the aliens should just materialize universal healthcare and give Bob a new girlfriend. The gallon of prevention that's worth a barrel of cure.
That is an absolutely incredible metabolism diagram even though it's incomplete. Imagine having one for the brain.
"SAM-e and tetrahydrobiopterin are cofactors for the enzymes tryptophan hydroxylase and tyrosine hydroxylase, which change the amino acids tryptophan and tyrosine into serotonin and dopamine, respectively. And serotonin and dopamine are known to be heavily involved in mood and energy level."
So is this why I sometimes get intense cravings for cheese? As in "I really need to eat some cheddar NOW"? Tyrosine in cheese -> dopamine?
In writing about complex adaptive systems (CAS) we fall into a couple attractor states - either they're still tractable because of the inherent predictability of *some* macro patterns, or they're so complicated because of the number of moving parts that you're shooting in the dark. And yet, despite the billions of variables that affect each part of the economy, we do tend to repeat certain patterns. Even if inadequate that still has some explanatory power.
My contention is that to get to a dynamical understanding, simulations are criminally underused as explanatory vehicles, especially in business/ economic settings (medicine too, though I don't know enough here). We'd need them to help us figure out the right level of abstraction to understand these attractors and the overall shape. (I explored this recently again (https://www.strangeloopcanon.com/p/simulating-understanding). It remains the biggest annoyance I've had against economics since grad school. I want to see the "biochemical pathways" flow diagram equivalent for money, so we can run scenarios and hone assumptions. They'll help us get a better understanding of the strange attractors within the system, while analytical/ predictive models tend to focus more on getting to an answer, which fails in cases of CAS. (This might be a false dichotomy.)
The mind seems a far more complex system than the economy in this instance, and I wonder how you'd even go about the problem of trying to create/ simulate something to get an understanding here.
Homocysteine, huh? Interesting, Sarah was talking about that just the other day on Twitter in the context of mortality rather than depression, and how it's possible that supplementing folate to reduce could be a good idea just in general (but how nobody's done a proper study of this): https://twitter.com/s_r_constantin/status/1356643626785378304
I'm curious, did you write most of these articles in the last couple of months, or the last couple of weeks?
How do I go about getting a prescription for Zxyxon? Also, you misspelled Vraylar®.
This is a fascinating post.
One possibly overly-pedantic query... Where it says, "I think the mind is at least this complicated," surely the mind can't be anywhere near as complicated as the global economy, given that billions of minds are themselves part of the economy?
These are nice, but I think it's a mistake to call them ontologies. They are models which, as you point out, capture a few salient points, but not the whole shtick. I think "ontology" in information science is best used to describe the underlying framework of a humanly-created system, where it can, in theory, be complete and even offer guidelines for further development. But "ontology" is too highfalutin a term for an approximate model of a large and complicated system that we have encountered from the outside and continue to study, many of whose fundamental inner details are unknown and will be for a long time, maybe forever. Using the term "ontology" gives the models more credence than they deserve, since an ontology is supposed to embody the axiomatic basis of the system is associated with, and those are unknown.
Thank you for allowing me to carp on the use of the term. Except for that, I liked your models and the point you are making.
Why wouldn't the attractor states make the taxometrics show a taxa, instead of a trait? Shouldn't the attractor states create multiple modes at the attractors?
Back in the taxometrics post, you had an example of an obvious taxa, humans vs bunnies. But if you included all the species along a continuous traversal through the evolutionary tree from humans to bunnies (i.e. back from humans to our common ancestor, then forward to bunnies), you'd have a smooth curve from human to bunny (smooth i.e. continuous, but not monotonic). Unless I've misunderstood taxometrics, I would imagine that including all those species would cause the statistics to lose the distinction of humans and bunnies as separate taxa, and instead to just conclude they were various parts of a rather large and skewed distribution.
The dynamic system, in this case, would be the environmental selection pressures that evolved the common ancestor towards humans and towards rabbits. It has the attractor states of human, and rabbit, which we can now statistically differentiate into separate taxa. If depression really does have attractor states that we can think of as "has depression" and "doesn't have depression", shouldn't that show up in the taxometrics, just like humans and rabbits do?
For anyone who's interested, I wrote a short post about how Borsboom's ideas might apply to chronic pain, which can very complex. https://www.bettermovement.org/blog/2017/pain-networks
This was a delight to read, and felt very natural to me. I've had similar thoughts and discussions about my own mental health, and my experiences with meditation. It also reminds me of everything I've read on SSC and elsewhere describing the mind in terms of a potential energy landscape.
Mostly, though, it reminded me of a recent discussion I had with a coworker about Zvi's lesswrong covid post where they (he?) used the phrase "pretend to pretend to try to try." Her reaction was, "I love that there's a forum out there with an audience that reads that sentence and nods along like it's a perfectly normal thing to say."
Thanks for creating a space where this kind of discussion is a perfectly normal thing to have.
if psychiatrists weren’t aware that some people have persistent depressive symptoms that occasionally get more severe until “double depression” came into the lexicon we are all fucked
Scott is slightly incorrect saying, “An enzyme in your body called MTHFR changes vitamin B9 into the active form l-methylfolate.” In reality, MTHFR changes the intermediate called methylenetetrahydrofolate (a form of folate three metabolic steps downstream from vitamin B9/folic acid) into l-methylfolate.
Why people are paying so much attention to MTHFR when any of the multiple folate cycle enzymes can go wrong? That is because of the so called genetic polymorphism 677C>T or, systematically, rs1801133, which in its homozygous form is present in 12% of Europeans. Homozygous rs1801133 (TT) results in a lower activity MTHFR enzyme (60% of normal activity).
Despite the hype surrounding companies like Genetic Genie, a very simple routine test any doctor (including Scott) can prescribe will tell you all you need to know about the state of your folate system. The test is called plasma total homocysteine, and it is very sensitive to the disruptions of folate metabolism. For example, a person with normal genotype has homocysteine level at 6-7 microM, but a person with rs1801133 (TT) has homocysteine at 10-11 microM. If you treat such a person with with 4 mg of folic acid per day their homocysteine goes down to 7 microM (see figure 3 in MTHFR 677C>T genotype is associated with folate and homocysteine concentrations in a large, population-based, double-blind trial of folic acid supplementation. https://pubmed.ncbi.nlm.nih.gov/21508090/ )
"Some mental disorders are pure traits without much dynamism – I think personality disorders, ADHD, and autism fall into this category."
What about the famous anecdotes of fevers relieving autism symptoms?
Imagine that these aliens had arrived at Earth during an earlier interglacial period. It would have been so much easier!
How many millions of years do we have to go back to make mental health that easy? Or would the previous interglacial be far enough?
"Some mental disorders are pure traits without much dynamism – I think personality disorders, ADHD, and autism fall into this category." Our seven-year old son has been diagnosed with combined type ADHD, ODD and "mild ASD" (exact words the paediatrician used). From my perspective, there is heaps of dynamism in his symptoms. Right now he is in a good phase, the school tells us he is following the rules, doing the work, even having positive social interactions with other students (he is in a mainstream classroom, not special education). But he has also had his bad phases. Last year, there were weeks when the school called us almost every day to come pick him up early because he has been physically violent against the school staff, and the school was trying to encourage us to pull him out of mainstream and send him to special education instead. (His private Catholic school only has mainstream classes, to go to special education we'd have to enrol him in another school.) There have been periods when I haven't been able to work because I've had to remove him from the home to stop him from physically attacking his mother. But, none of that right now, we are hoping and praying the current good phase lasts, yet we've had good phases that didn't last before. Is that anecdotal evidence against the idea that ADHD and autism are "pure traits without much dynamism"?
I like the humility of this post. The brain, society, etc. are _grand_ things.
"Or a recession caused by deregulation of banks causing them to offer too many subprime loans causing all of them to go belly-up at once"
Were any of the pro-regulation people saying the banks needed to be regulated so they gave <I>fewer</I> subprime loans before the recession happened?
For those interested in dynamical systems and the brain - check out Chris Eliasmith and his lab http://watarts.uwaterloo.ca/~celiasmi/cv.html
> What we know about metabolism so far looks like this...
As complex and intimidating as that chart seems, it's really not even the half of it. It's missing:
- Bile acids
- Prostaglandins
- NO signaling and more detailed arginine metabolism (e.g., S-Nitrosoglutathione)
- Advanced glycation end-products and their metabolism (e.g., glucosepane)
- Endocannabinoids (which overlaps with endogenous TRPV agonist metabolism, also not on the chart.)
And much, much more.
A full chart, even one that's restricted only to what's currently known, would be at least five times the size. Which, I suppose, sharpens your point.
Completely foreign and exotic aliens which have no corresponding concepts for "War" and "Money", but can perform sentiment analysis to figure out likes/dislikes from facial expressions? They might not even have faces!
I'm just gonna add a little to the dynamical system and attractors perspective - sometimes a dynamical system has attractors which are not points in phase-space (ie, the multidimensional space of possible states of the system) but rather closed lines (limit cycles). This would mean that the system travels along those lines in a periodic way, and any other orbit in phase space eventually reaches these closed lines. A physical example of this is a mass on a spring with friction that sometimes slows it down and other times speeds it up (van der Pol oscillator).
Do you think this could be a good way to understand disorders which have periodic behavior? Say, is bipolar manic and depressive episodes better understood as "external shocks move the system between stable points", or "the internal dynamics of the system moves it along a periodic trajectory between two extremes"?
Tangent - "But also, the refinery workers might strike in sympathy with the truckers" is a problem that a robust system of social castes solves! If refining and transportation are done by two separate tribes who don't interact socially, don't intermarry, and don't try to horn in on each other's economic domains, then the odds of one tribe paying a cost to show sympathy to the other at the same time that that other tribe is purposefully making things difficult for the first one are essentially nil.
This was a fantastic read. Thank you.
I wonder if a dice roll is a dynamic system with 6 attractor states? It seems like there is some graph that maps a dice leaving the player's hand to its resting state on one face, but the graph is so large that we can't understand it as a system and so think of it as random.
I don't mean to be cynical. It's more important to understand the economy and our mental health than it is to understand which way a dice will fall. Maybe it's even more important to understand just how hard that endeavour is and remind ourselves that anyone who is too confident in their interventions is (at best) a benevolent alien.
Thanks again!
I saw that metabolism diagram and my immediate reaction was "Wow, it's like the US military's procurement system!" https://graylinegroup.com/wp-content/uploads/2017/05/atl_wall_chart-1.jpg
Typo:
"People often ask: is depression the just same thing as normal sadness?" -> "just the same thing"
>MTHFR
Can I be the only one who mentally expands this into Samuel L Jackson's favourite epithet?
I probably was, but maybe now others will suffer with me.
Have I created a new attractor state?
“large stimulus packages can sometimes shift the system from recession to normal growth”
To economists out there: is there an example of this actually happening? I know the Great Depression is the era most associated with Keynesian economics, but my understanding is that the increase in taxes (starting under Hoover) made policy not all that Keynesian, and it lasted a long time (even having another recession prior to full recovery).
The APA joke got me; I literally laughed out loud. Weirdly enough, this is the most true description of trying to treat depression I've ever seen.
Scott, can you please write something about ketamine, which is revolutionizing mental health?
I wonder what you make of this one:
"Bupropion Normalizes Cognitive Performance in Patients With Depression"
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1924979/
Bogus or legit?
First time here. Great article!
I'm attaching a celebrated paper which talks about the neuroscience of memory retrieval. It also takes the dynamical systems approach in order to explain how we retrieve memories in our brain. The strength of the paper lies in the fact that it does not make strong assumptions about the brain, and most parameters can be "random". https://www.pnas.org/content/79/8/2554
As an English computer scientist, I was confused both by your use of "gas" to mean "petrol" (I assumed by "gas lines" you meant "pipes for natural gas", not "petrol queues") and your use of "i" and "j" for boolean variables rather than indices.
Just wanted to note that Scott's drawings may be slightly misleading. Critical slowing down is a feature that appears only when the system is going from one macro state to the other (the attractors in Scott's language, although the phenomena occurs in non dynamical systems too), but not in the vicinity of the basin of attraction, so no slowing down near an attractor, even though the drawing might suggest that due to the ground being level there.
It's also funny that the link toward an example of critical slowing down in the global economy is an article claiming there is no evidence for it, which seems to conform to a brief internet search on the terms.
On the very misleading side is calling something fractally complicated due to having causes that have causes,etc. The defining feature of a fractal is self-similarity, so that you do not have to know the underlying cause, everything you need to know is at whichever scale you're looking at and you can understand this scale while completely oblivious to finer details (which are just more of the same).
I'm happy that Scott is back and double happy he is posting very regularly, but throughout the first parts I felt being constantly threatened with math and links to peer-review until I stopped to review some things.
As an expert in dynamical systems, I like this way of looking at the world. Most things are dynamical, and have many variables. A dynamical model of the brain would probably have to contain as many variables as there are neurons. That being said, a surprisingly large number of complicated things behave as if they only have a low number of variables. For example, the transition to turbulence can (usually) be well understood using ideas of chaos theory with a few variables. These sorts of reductions require some sort of continuity or dissipation, which are lacking in the brain or the economy.
I want to correct one error: the opening example has only one dynamical variable. The system can be written in one line, using the sign function (which is +1 if the input is positive and -1 if the input is negative - and for this example, we also want sgn(0) = +1).
h(t+1) = h(t) + sgn( h(t) - 75 )
If it did have more than one dynamical variable, you wouldn't have been able to understand what it does using a one dimensional picture. The picture would be more accurate as a tent, with straight lines going up to a point above 75.
I loved Borsboom papers when they were published, but I've seen criticism about their replication (https://psych-networks.com/network-models-do-not-replicate-not/ and https://psych-networks.com/7-new-papers-network-replicability/); I guess in order to strenghten the model, unsurpisingly, more research is needed.
On a tangential note I suffer from atypical depression, though it's likely that my attractors are shallow and I'm moving among those faster than classic MDD (I suspect this being linked to my Delayed Sleep Phase Syndrome messing up the circadian rhytm). My diagnosis could also be incorrect since it's more similar to cyclothymia
This is an interesting and illuminative post. I wonder though about the overly exclusive physiological perspective. I agree the physiological complexity is staggering but there seem to be 2 additional areas left out though you do refer to them obliquely.
The feedback loops created by the external environment and the recursive element of the mind whether conscious or unconscious. Your distinction that the difference between sadness and depression might be that depression is a "stable" attractor state is one I'm not sure I agree with. It could be that there is some variable susceptibility but could it not be the feedback between all 3 systems that deepens the state so that it's difficult to emerge from it without help. If that was true it would perhaps explain why there is no substantive difference between sadness and depression at the outset. I am extending the inference of course that duration is the defining difference, as suggested by taxometrics, and that it's the complex dynamic feedback loops that deepens and creates your attractor state?