Eliezer: I generally like your posts, but I disagree with you here. I think that there’s at least one really useful definition of the word emergence (and possibly several useless ones).
It’s true, of course (at least to a materialist like me), that every phenomenon emerges from subatomic physics, and so can be called ‘emergent’ in that sense. But if I ask you why you made this post, your answer isn’t going to be, “That’s how the quarks interacted!” Our causal models of the world have many layers between subatomic particles and perceived phenomena. Emergence refers to the relationship between a phenomenon and its immediate cause.
So, for instance, suppose I’m on the interstate and I get caught in a traffic jam. I might wonder why there’s a huge jam on the road. It’s possible that there’s a simple, straightforward explanation: “There’s a ten-car pileup a mile further on, and five of the six lanes are shut down. That’s why there’s a traffic jam.” Obviously we could get far more reductionist— both in terms of “why is there a pileup” and “why does a pileup cause a traffic jam”—but for the conceptual level we’re operating on, the pileup is a full and complete answer. And thus the traffic jam isn’t an ‘emergent’ phenomenon; it has one major identifiable cause.
In contrast, a lot of traffic jams ‘just happen.’ The previous sentence is false, strictly speaking; the jams come from somewhere. But you can’t point to an individual cause of them; they arise from the local effects of millions of local actions taken by individual drivers. Removing any one of these actions wouldn’t eliminate the jam; it’s a cumulative product of all of them. So people searching for an explanation of why it takes two hours to dive ten miles in rush hour get really frustrated, because there’s no good explanation to give them. And people trying to fix rush hour get even more frustrated, because there’s no good angle to attack the problem from.
So emergence, in this sense, means that a phenomenon has many intertwined causes, rather than one or two identifiable and major causes. It turns out, of course, that most interesting phenomena are emergent (non-emergent phenomena are, by definition, boring, since their causes are straightforward). But “emergence” is useful as a shorthand for “the causes are complicated and interconnected, and I can’t pick one out and tell you, ‘here it is, this is why that happened.’” It’s important not to get confused, and not to think an explanation of why we don’t understand something is the same as an explanation of that thing. But as long as you remember that, it’s a useful thing to remember.
In contrast, a lot of traffic jams ‘just happen.’ The previous sentence is false, strictly speaking; the jams come from somewhere. But you can’t point to an individual cause of them; they arise from the local effects of millions of local actions taken by individual drivers.
I’ve actually seen a study on these types of jams, though I cannot remember the source. The results were pretty simple and surprising. The research discovered they could create a massive traffic jam on a full but still flowing highway by simply having a single car brake for longer than necessary.
The first person would brake for too long, causing the person behind him to brake for slightly longer (he isn’t likely to brake for less time than the person ahead of him lest he risk an accident), which continued down the line, a chain reaction. Drivers in the lanes on either side of the initial brake chain would also begin braking as they saw people in the central lane brake, being sensibly cautious during rush hour, which would spread outward from their positions. Eventually traffic would halt, as the people ahead would have to stop completely before being able to move again.
I’m sure there was some kind of cutoff threshold regarding how long over the necessary length of time the first person has to break, but it wasn’t very long, a second or two would do it during a non-jammed rush hour.
It also explains why, once a jam occurs for any reason, it is extremely slow to clear up even after the cause of the jam is long since removed.
Pretty shocking really, and certainly not an “emergent phenomena”. That’s why EY is against using emergence for everything—there absolutely must be a reason, and that reason cannot be “lots of stuff interacts and now we get a traffic jam!” Using emergence as an explanation encourages you to stop thinking about the problem, rather than dig in and figure out why what happened happens.
You have unexplained traffic jams—do you call it emergence or try to explain them? The rational thing to do is to try to explain them in a way that allows you to have expectations about future observations.
In other words, “Emergence” is an answer looking for a problem.
Yes, the point is to be sure you aren’t using “Emergence” or “Emergent Phenomena” as stop signs. That you recognize that there is in fact a cause (or causes) for what you are seeing, and if the total seems to be more than the sum of its parts, that there is some mechanism that exists that is amplifying the effects.
Eliezer: I generally like your posts, but I disagree with you here. I think that there’s at least one really useful definition of the word emergence (and possibly several useless ones).
It’s true, of course (at least to a materialist like me), that every phenomenon emerges from subatomic physics, and so can be called ‘emergent’ in that sense. But if I ask you why you made this post, your answer isn’t going to be, “That’s how the quarks interacted!” Our causal models of the world have many layers between subatomic particles and perceived phenomena. Emergence refers to the relationship between a phenomenon and its immediate cause.
So, for instance, suppose I’m on the interstate and I get caught in a traffic jam. I might wonder why there’s a huge jam on the road. It’s possible that there’s a simple, straightforward explanation: “There’s a ten-car pileup a mile further on, and five of the six lanes are shut down. That’s why there’s a traffic jam.” Obviously we could get far more reductionist— both in terms of “why is there a pileup” and “why does a pileup cause a traffic jam”—but for the conceptual level we’re operating on, the pileup is a full and complete answer. And thus the traffic jam isn’t an ‘emergent’ phenomenon; it has one major identifiable cause.
In contrast, a lot of traffic jams ‘just happen.’ The previous sentence is false, strictly speaking; the jams come from somewhere. But you can’t point to an individual cause of them; they arise from the local effects of millions of local actions taken by individual drivers. Removing any one of these actions wouldn’t eliminate the jam; it’s a cumulative product of all of them. So people searching for an explanation of why it takes two hours to dive ten miles in rush hour get really frustrated, because there’s no good explanation to give them. And people trying to fix rush hour get even more frustrated, because there’s no good angle to attack the problem from.
So emergence, in this sense, means that a phenomenon has many intertwined causes, rather than one or two identifiable and major causes. It turns out, of course, that most interesting phenomena are emergent (non-emergent phenomena are, by definition, boring, since their causes are straightforward). But “emergence” is useful as a shorthand for “the causes are complicated and interconnected, and I can’t pick one out and tell you, ‘here it is, this is why that happened.’” It’s important not to get confused, and not to think an explanation of why we don’t understand something is the same as an explanation of that thing. But as long as you remember that, it’s a useful thing to remember.
I’ve actually seen a study on these types of jams, though I cannot remember the source. The results were pretty simple and surprising. The research discovered they could create a massive traffic jam on a full but still flowing highway by simply having a single car brake for longer than necessary.
The first person would brake for too long, causing the person behind him to brake for slightly longer (he isn’t likely to brake for less time than the person ahead of him lest he risk an accident), which continued down the line, a chain reaction. Drivers in the lanes on either side of the initial brake chain would also begin braking as they saw people in the central lane brake, being sensibly cautious during rush hour, which would spread outward from their positions. Eventually traffic would halt, as the people ahead would have to stop completely before being able to move again.
I’m sure there was some kind of cutoff threshold regarding how long over the necessary length of time the first person has to break, but it wasn’t very long, a second or two would do it during a non-jammed rush hour.
It also explains why, once a jam occurs for any reason, it is extremely slow to clear up even after the cause of the jam is long since removed.
Pretty shocking really, and certainly not an “emergent phenomena”. That’s why EY is against using emergence for everything—there absolutely must be a reason, and that reason cannot be “lots of stuff interacts and now we get a traffic jam!” Using emergence as an explanation encourages you to stop thinking about the problem, rather than dig in and figure out why what happened happens.
You have unexplained traffic jams—do you call it emergence or try to explain them? The rational thing to do is to try to explain them in a way that allows you to have expectations about future observations.
In other words, “Emergence” is an answer looking for a problem.
“Emergence” here would be a reference to the non-linear result of the braking. Like what Henry_V said.
Yes, the point is to be sure you aren’t using “Emergence” or “Emergent Phenomena” as stop signs. That you recognize that there is in fact a cause (or causes) for what you are seeing, and if the total seems to be more than the sum of its parts, that there is some mechanism that exists that is amplifying the effects.
Emergence is not an explanation by itself.