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I would definitely make it every other week, if it's weekly.


I agree that something unusual is going on. Humans, unlike any other species I'm aware of, are voluntarily restricting our own population growth. But I don't know why you say that there's "no reason" to believe that this strange behavior might benefit us. Surely you can think of at least one reason? After all, all those other species that don't voluntarily limit their own reproduction eventually see their populations crash, or level off in the face of fierce competition over resources, when they meet or exceed their environment's carrying capacity. The laws of physics as we currently understand them dictate that exponential growth cannot continue forever.

I'm not saying that there are no foreseeable downsides to population leveling off. And I'm not saying that there's no risk of unforeseeable consequences of the social changes underlying this demographic shift. But I am saying that (amid all the pros and cons) there is one obvious, important reason why human population leveling off might be a good thing. The downsides are neither so obvious nor so potentially dramatic. To illustrate this, lets look at Last's (awful) WSJ article quoted in the Marginal Revolutions post.

Last does his best to paint declining fertility as a nightmare scenario. But the data he presents simply don't support his tone. For example:

Low-fertility societies don't innovate because their incentives for consumption tilt overwhelmingly toward health care. They don't invest aggressively because, with the average age skewing higher, capital shifts to preserving and extending life and then begins drawing down.

In other words, low-fertility societies do have an incentive to innovate - in medicine and life extension. And not just for the benefit of the old - they also have an incentive to keep the young healthy and productive as long as possible, to maintain their shrinking workforce (which may go some ways toward explaining Japan's excellent school nutrition program, and low, declining childhood obesity rates). They also have an incentive to develop automation to replace aging workers, which I know is a major reason that Japan is a leader in robotics. Let's take a closer look at Japan:

From 1950 to 1973, Japan's total-factor productivity—a good measure of economic dynamism—increased by an average of 5.4% per year. From 1990 to 2006, it increased by just 0.63% per year. Since 1991, Japan's rate of GDP growth has exceeded 2.5% in only four years; its annual rate of growth has averaged 1.03%.

Wait, did he just admit that Japan's economy is still growing? Yep, both GDP and GDP/capita have continued to grow, albeit more slowly, since the 1990s. Let that sink in a moment. The Japanese are, on average, working less than they used to. They're older and more likely to be retired. And yet they still get to enjoy having more stuff. (Largely thanks to innovations in automation driven, in part, by aging demographics.) And thanks to medical innovations, driven in part by aging demographics, they will continue enjoying that stuff longer than any generation before. So where's the grim cautionary tale? Last has none, just this:

At the current fertility rate, by 2100 Japan's population will be less than half what it is now.

Which would still be more than it was in 1900. So, where's the problem? Why is it preferable to keep taxing the earth's resources with more and more people with no foreseeable prospects at space colonization? On overpopulation, Last says,

First, global population growth is slowing to a halt and will begin to shrink within 60 years.

This is just unforgivably bad logic: 'Overpopulation isn't a problem, because population is leveling off, because fertility is declining. Therefore we must act immediately to put a stop to declining fertility!' If we ever do face a shrinking population, I'd rather deal with it by increasing healthy lifespans than by increasing birthrates.


I downvoted common_law's post, because of some clear-cut math errors, which I pointed out. I'm downvoting your comment because it's not saying anything constructive.

There's nothing wrong with what common_law was trying to do here, which is to show that infinite sets shouldn't be part of our ontology. Experience can't be the sole arbiter of which model of reality is best; there is also parsimony. Whether infinite quantities are actually real, is no less worthy of discussion than whether MWI is actually real, or merely a computational convenience. I only agree with you that the math lacked rigor. This is discussion, so I don't see a problem with posting things that need to be corrected, but I had to downvote the post because it might have confused someone who didn't notice the errors.


I agree with premise (1), that there is no reason to think of infinitesimal quantities as actually part of the universe. I don't agree with premise (2), that actual infinities imply actual infinitesimals. If you could convince me of (2), I would probably reject (1) rather than accept (3). Since an argument for (2) would be a good argument against (1), given that our universe does seem to have actual infinities.

the points on a line are of infinitesimal dimension ... yet compose lines finite in extent.

No. Points have zero dimension. "Infinitesimal" is something else. There are no infinitesimal numbers on the real line (or in the complex plane, for that matter), and no subinterval of the real line has infinitesimal length, so we would have to extend the number system if we wanted to think of infinitesimals as numbers.

When I raise the same argument about an infinite set, you can't reply that you can always make the set bigger; if I say add an element, you reply that the sets are still the same size (cardinality).

But there is a way to use an infinite set to construct a larger infinite set: - the power set. I don't understand the rest of this paragraph.

Consider again the points on a 3-inch line segement. If there are infinitely many, then each must be infinitesimal.

Again, single points have zero length, not infinitesimal length. Note, though, that there are ways to partition a finite line segment into infinitely many finite line segmets, including the partition that Zeno proposed: 1/2 + 1/4 + 1/8 + ... In an integration, we (conceptually) break up the domain into infinitely many infinitesimally wide intervals, but this is just an intuition. None of the formal definitions of integrals I've seen actually say anything about an infinitesimally wide interval.

The series comes infinitesimally close to the limit, and in this context, we treat the infinitesimal as if it were zero.

Actually, we don't have to treat an infinitesimal as zero, we just have to treat zero as zero. If I move along a meter stick at one meter per second, then according to Zeno's construction, I traverse half the distance in 1/2 second, 3/4 of the distance in 3/4 of a second, and so on. As you say, after one second, I have traversed every point on the meter stick except the very last point, because the union of the closed intervals [0,1/2], [1/2,3/4], [3/4,7/8], ... is the half-open interval [0,1). So how much longer does it take me to traverse that last point? Zero seconds, because a single point has zero length. There is no contradiction, and no need to use infinitesimals.


Fascinating. But note that these are still very old people with declining cholesterol as they age. The study is more relevant to physicians deciding whether to prescribe statins to their elderly patients, and less relevant to young people deciding whether to keep cholesterol low throughout life with diet.

I'd need to read the whole study, but what I see so far doesn't even contradict the hypothesis I outlined. The abstract says that people who had low cholesterol at the last two examinations did worse than people who had low cholesterol at only the last examination. But most of these old people had declining cholesterol. So maybe this just means that the earlier your cholesterol starts to decline from aging, the sooner you die.

Anyway, I put more stock in the cross-cultural epidemiology and intervention trials, than in these observational studies trying to parse small differences within relatively homogeneous, free-living populations. We know that the longest-lived, healthiest populations in the world ate a low saturated-fat diet that induces low cholesterol. And we know that Dean Ornish was able to reverse heart disease with a lifestyle intervention including a cholesterol-lowering diet. Show me a population as healthy as the Okinawans with high cholesterol, or an intervention as effective as Ornish's without lowering cholesterol, and I'll reconsider. Otherwise, I do consider the issue settled from a pragmatic perspective, even if some of the academic questions remain to be answered. That is, it may be possible to have a healthy lifestyle that raises cholesterol, but we don't have any proven examples of such a lifestyle to emulate, do we? Mike Darwin gave a good explanation of this idea in "Interventive Gerontology".


This (admittedly biased) youtuber has a pretty thorough criticism of the study. The bottom line is that cholesterol tends to drop off before death (6:26 in the video), not just because cholesterol-lowering medications are administered to those at highest risk of heart attack (as Kawoomba points out), but also because of other diseases. When you correct for this, or follow people throughout their lives, this reverse causation effect disappears, and you find exactly the association you would expect: higher cholesterol associates with higher cardiovascular and total mortality (10:21).

I think that studies like this one are like studies showing that overweight is "protective" against mortality - when the obvious alternative explanation is that smoking, cancer, and other diseases can prevent weight gain, or cause weight loss, just before they kill you! Obviously, this would mask or even reverse the association between overweight (high cholesterol) and death, even if overweight (high cholesterol) causes death.


Agreed. The multiverse idea is older than, and independent of quantum theory. Actually, a single infinitely large classical universe will do, since statistically, every possibility should play out. Nietzsche even had a version of immortality based on an infinitely old universe. Though it's not clear whether he ever meant it literally, he very well could have, because it was consistent with the scientific understanding of the time.

That said, I like the idea of sminux's post. I try to steer clear of quantum language myself, and think others should too, if all they mean by "quantum" is "random".


All the possible reasons for the conflict you listed suggest that the solution is to help feminists understand evolutionary psychology better, so they won't have a knee-jerk defensive reaction against it. This could come off as a little condescending, but more importantly, it misses the other side of the issue. In order to leave itself less open to criticism, evolutionary psychology could be more rigorous, just as other "soft" sciences like medicine and nutrition could be more rigorous. This would make it harder for critics to find things to object to, increasing trust in the field over time, and would probably be a good thing in itself anyway.

So I would add to your list: 8) Concerns about lack of rigor in the field of evolutionary psychology.


Actually I'm not sure if any of that is a problem. Spaun is quite literally "anthropomorphic" - modeled after a human brain. So it's not much of a stretch to say that it learns and understands the way a human does. I was just pointing out that the more progress we make on human-like AIs, without progress on brain scanning, the less likely a Hansonian singularity (dominated by ems of former humans) becomes. If Spaun as it is now really does work "just like a human", then building a human-level AI is just a matter of speeding it up. So by the time we have computers capable of supporting a human mind upload, we'll already have computer programs at least as smart as humans, which learn their knowledge on their own, with no need for a knowledge transplant from a human.


I think we need to separate the concept of whole brain emulation, from that of biology-inspired human-like AI. This actually looks pretty bad for Robin Hanson's singularity hypothesis, where the first emulations to perfectly emulate existing humans suddenly make the cost of labor drop dramatically. If this research pans out, then we could have a "soft takeoff", where AI slowly catches up to us, and slowly overtakes us.

CNRG_UWaterloo, regarding mind uploads:

Being able to simulate a particular person's brain is incredibly far away. There aren't any particularly good ideas as to how we might be able to reasonably read out that sort of information from a person's brain. That said, there are also lots of uses that a repressive state would have for any intelligent system (think of automatically scanning all surveillence camera footage). But, you don't want a realistic model of the brain to do that -- it's get bored exactly as fast as people do.

So we should expect machine labor to gradually replace human labor, exactly as it has since the beginning of the industrial revolution, as more and more capabilities are added, with "whole brain emulation" being one of the last features needed to make machines with all the capabilities of humans (if this step is even necessary). It's possible, of course, that we could wind up in a situation where the "last piece of the puzzle" turns out to be hugely important, but I don't see any particular reason to think that will happen.

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