It’s not the case that there are N technologies and progress consists solely of improving those technologies; progress usually happens by developing new technologies.
Yeah, I agree with that. :)
But I think we can still point to some important underlying measures — say, “the speed at which we transmit signals around Earth” or “the efficiency with which we can harvest solar energy” — where there isn’t much room for further progress. On the first of those two measures, there basically isn’t any room for further progress. On the second, we can at the very most see ~a doubling from where we currently are, whereas we have seen more than a 40x increase since the earliest solar cells in the late 1800s. Those are some instances of progress that cannot be repeated (within those domains), even if we create new technologies within these domains.
Of course, there may be untapped domains that could prove similarly significant for growth. But I still think the increasing number of domains in which past growth accomplishments cannot be repeated provides a modest reason to doubt a future growth explosion. As noted, I don’t think any of the reasons I listed are strong in themselves, but when combined with the other reasons, including the decline in innovations per capita, recent empirical trends in hardware progress, the relatively imminent limits in the growth of information processing (less than 250 years at current growth rates), and the point about the potential difficulties of explosive growth given limited efficiency gains I made here, I do think a growth explosion begins to look rather unlikely, especially one that implies >1000 percent annual growth (corresponding to an economy that doubles ~every three months or faster).
You’re trying to argue for “there are no / very few important technologies with massive room for growth” by giving examples of specific things without massive room for growth.
In general arguing for “there is no X that satisfies Y” by giving examples of individual Xs that don’t satisfy Y is going to be pretty rough and not very persuasive to me, unless there’s some reason that can be abstracted out of the individual examples that is likely to apply to all Xs, which I don’t see in this case. I don’t care much whether the examples are technologies or measures (though I do agree measures are better).
(I’m also less convinced because I can immediately think of related measures where it seems like we have lots of room to grow, like “the speed at which we can cost-effectively transmit matter around Earth” or “the efficiency with which we can harvest fusion energy”.)
For similar reasons I don’t update much on empirical trends in hardware progress (there’s still tons of progress to be made in software, and still tons of progress to be made in areas other than computing).
I agree that explosive growth looks unlikely without efficiency gains; “no efficiency gains” means that the positive feedback loop that drives hyperbolic growth isn’t happening. (But for this to move me I need to believe “no/limited efficiency gains”.)
I think the decline in innovations per capita is the strongest challenge to this view; I just don’t really see the others as significant evidence one way or the other.
You’re trying to argue for “there are no / very few important technologies with massive room for growth” by giving examples of specific things without massive room for growth.
I should clarify that I’m not trying to argue for that claim, which is not a claim that I endorse.
My view on this is rather that there seem to be several key technologies and measures of progress that have very limited room for further growth, and the ~zero-to-one growth that occurred along many of these key dimensions seems to have been low-hanging fruit that coincided with the high growth rates that we observed around the mid-1900s. And I think this counts as modest evidence against a future growth explosion.
That is, my sense from reading Gordon and others is that the high growth rates of the 20th century were in large part driven by a confluence of innovations across many different technological domains — innovations that people such as Gordon and Cowen roughly describe as low-hanging innovations that are no longer (as readily) accessible. This, combined with the empirical observation that growth rates have been declining since the 1960s, and the observation that innovations per capita have decreased, seems to me convergent (albeit in itself still quite tentative) evidence in favor of the claim that we will not see explosive growth in the future, as this “low-hanging fruit picture” renders a similar — and especially a greater — such confluence of progress less likely to occur again. And I would regard each of those lines of evidence to be significant. (Of course, these lines of evidence are closely related; e.g. the decline in innovations per capita might be seen as a consequence of our having already reaped the most significant innovations in many — though by no means all — key domains.)
I also think it’s important to distinguish 1) how much room for growth that various technologies have, and 2) how likely it is that we will see a growth explosion. My view is that we are (obviously) quite far from the ultimate limits in many domains, but that future growth will most likely be non-explosive, partly because future innovations seem much harder to reap compared to past innovations (and partly for the other reasons outlined in the post).
So while I think a future growth explosion is unlikely, I still think that there is considerable room for growth in an absolute sense, even if the room for growth is morelimited than we might intuitively expect.
My view on this is rather that there seem to be several key technologies and measures of progress that have very limited room for further growth, and the ~zero-to-one growth that occurred along many of these key dimensions seems to have been low-hanging fruit that coincided with the high growth rates that we observed around the mid-1900s. And I think this counts as modest evidence against a future growth explosion.
Hmm, it seems to me like these observations are all predicted by the model I’m advocating, so I don’t see why they’re evidence against that model. (Which is why I incorrectly thought you were instead saying that there wasn’t room for much growth, sorry for the misunderstanding.)
(I do agree that declining growth rates are evidence against the model.)
At any given point in time, I expect that progress looks like “taking the low-hanging fruit”; the reason growth goes up over time anyway is because there’s a lot more effort looking for fruit as time goes on, and it turns out that effect dominates.
For example, around 0 AD you might have said “recent millennia have had much higher growth rates because of the innovations of agriculture, cities and trade, which allowed for more efficient food production and thus specialization of labor. The zero-to-one growth on these key dimensions was low-hanging fruit, so this is modest evidence against further increases in growth in the future”; that would have been been an update in the wrong direction.
At any given point in time, I expect that progress looks like “taking the low-hanging fruit”; the reason growth goes up over time anyway is because there’s a lot more effort looking for fruit as time goes on, and it turns out that effect dominates.
I think the empirical data suggests that that effect generally doesn’t dominate anymore, and that it hasn’t dominated in the economy as a whole for the last ~3 doublings. For example, US Total Factor Productivity growth has been weakly declining for several decades despite superlinear growth in the effective number of researchers.
I think the example of 0 AD is disanalogous because there wasn’t a zero-to-one growth along similarly significant and fundamental dimensions (e.g. hitting the ultimate limit in the speed of communication) followed by an unprecedented growth decline that further (weakly) supports that we’re past the inflection point, i.e. past peak growth rates.
Yeah, I agree with that. :)
But I think we can still point to some important underlying measures — say, “the speed at which we transmit signals around Earth” or “the efficiency with which we can harvest solar energy” — where there isn’t much room for further progress. On the first of those two measures, there basically isn’t any room for further progress. On the second, we can at the very most see ~a doubling from where we currently are, whereas we have seen more than a 40x increase since the earliest solar cells in the late 1800s. Those are some instances of progress that cannot be repeated (within those domains), even if we create new technologies within these domains.
Of course, there may be untapped domains that could prove similarly significant for growth. But I still think the increasing number of domains in which past growth accomplishments cannot be repeated provides a modest reason to doubt a future growth explosion. As noted, I don’t think any of the reasons I listed are strong in themselves, but when combined with the other reasons, including the decline in innovations per capita, recent empirical trends in hardware progress, the relatively imminent limits in the growth of information processing (less than 250 years at current growth rates), and the point about the potential difficulties of explosive growth given limited efficiency gains I made here, I do think a growth explosion begins to look rather unlikely, especially one that implies >1000 percent annual growth (corresponding to an economy that doubles ~every three months or faster).
You’re trying to argue for “there are no / very few important technologies with massive room for growth” by giving examples of specific things without massive room for growth.
In general arguing for “there is no X that satisfies Y” by giving examples of individual Xs that don’t satisfy Y is going to be pretty rough and not very persuasive to me, unless there’s some reason that can be abstracted out of the individual examples that is likely to apply to all Xs, which I don’t see in this case. I don’t care much whether the examples are technologies or measures (though I do agree measures are better).
(I’m also less convinced because I can immediately think of related measures where it seems like we have lots of room to grow, like “the speed at which we can cost-effectively transmit matter around Earth” or “the efficiency with which we can harvest fusion energy”.)
For similar reasons I don’t update much on empirical trends in hardware progress (there’s still tons of progress to be made in software, and still tons of progress to be made in areas other than computing).
I agree that explosive growth looks unlikely without efficiency gains; “no efficiency gains” means that the positive feedback loop that drives hyperbolic growth isn’t happening. (But for this to move me I need to believe “no/limited efficiency gains”.)
I think the decline in innovations per capita is the strongest challenge to this view; I just don’t really see the others as significant evidence one way or the other.
I should clarify that I’m not trying to argue for that claim, which is not a claim that I endorse.
My view on this is rather that there seem to be several key technologies and measures of progress that have very limited room for further growth, and the ~zero-to-one growth that occurred along many of these key dimensions seems to have been low-hanging fruit that coincided with the high growth rates that we observed around the mid-1900s. And I think this counts as modest evidence against a future growth explosion.
That is, my sense from reading Gordon and others is that the high growth rates of the 20th century were in large part driven by a confluence of innovations across many different technological domains — innovations that people such as Gordon and Cowen roughly describe as low-hanging innovations that are no longer (as readily) accessible. This, combined with the empirical observation that growth rates have been declining since the 1960s, and the observation that innovations per capita have decreased, seems to me convergent (albeit in itself still quite tentative) evidence in favor of the claim that we will not see explosive growth in the future, as this “low-hanging fruit picture” renders a similar — and especially a greater — such confluence of progress less likely to occur again. And I would regard each of those lines of evidence to be significant. (Of course, these lines of evidence are closely related; e.g. the decline in innovations per capita might be seen as a consequence of our having already reaped the most significant innovations in many — though by no means all — key domains.)
I also think it’s important to distinguish 1) how much room for growth that various technologies have, and 2) how likely it is that we will see a growth explosion. My view is that we are (obviously) quite far from the ultimate limits in many domains, but that future growth will most likely be non-explosive, partly because future innovations seem much harder to reap compared to past innovations (and partly for the other reasons outlined in the post).
So while I think a future growth explosion is unlikely, I still think that there is considerable room for growth in an absolute sense, even if the room for growth is more limited than we might intuitively expect.
Hmm, it seems to me like these observations are all predicted by the model I’m advocating, so I don’t see why they’re evidence against that model. (Which is why I incorrectly thought you were instead saying that there wasn’t room for much growth, sorry for the misunderstanding.)
(I do agree that declining growth rates are evidence against the model.)
At any given point in time, I expect that progress looks like “taking the low-hanging fruit”; the reason growth goes up over time anyway is because there’s a lot more effort looking for fruit as time goes on, and it turns out that effect dominates.
For example, around 0 AD you might have said “recent millennia have had much higher growth rates because of the innovations of agriculture, cities and trade, which allowed for more efficient food production and thus specialization of labor. The zero-to-one growth on these key dimensions was low-hanging fruit, so this is modest evidence against further increases in growth in the future”; that would have been been an update in the wrong direction.
I think the empirical data suggests that that effect generally doesn’t dominate anymore, and that it hasn’t dominated in the economy as a whole for the last ~3 doublings. For example, US Total Factor Productivity growth has been weakly declining for several decades despite superlinear growth in the effective number of researchers.
I think the example of 0 AD is disanalogous because there wasn’t a zero-to-one growth along similarly significant and fundamental dimensions (e.g. hitting the ultimate limit in the speed of communication) followed by an unprecedented growth decline that further (weakly) supports that we’re past the inflection point, i.e. past peak growth rates.