Saturday, December 22, 2012

Future Filter Fatalism


Cross-posted from Overcoming Bias

One of the more colorful vignettes in philosophy is Gibbard and Harper's "Death in Damascus" case:
Consider the story of the man who met Death in Damascus. Death looked surprised, but then recovered his ghastly composure and said, ‘I am coming for you tomorrow’. The terrified man that night bought a camel and rode to Aleppo. The next day, Death knocked on the door of the room where he was hiding, and said I have come for you’.
‘But I thought you would be looking for me in Damascus’, said the man.
‘Not at all’, said Death ‘that is why I was surprised to see you yesterday. I knew that today I was to find you in Aleppo’.
That is, Death's foresight takes into account any reactions to Death's activities.
Now suppose you think that a large portion of the Great Filter lies ahead, so that almost all civilizations like ours fail to colonize the stars. This implies that civilizations almost never adopt strategies that effectively avert doom and allow colonization. Thus the mere fact that we adopt any purported Filter-avoiding strategy S is strong evidence that S won't work, just as the fact that you adopt any particular plan to escape Death indicates that it will fail.

To expect S to work we would have to be very confident that we were highly unusual in adopting S (or any strategy as good as S), in addition to thinking S very good on the merits. This burden might be met if it was only through some bizarre fluke that S became possible, and a strategy might improve our chances even though we would remain almost certain to fail, but common features, such as awareness of the Great Filter, would not suffice to avoid future filters.

Thursday, December 06, 2012

Breeding happier animals: no futuristic tech required


[Cross-posted from Overcoming Bias; edited to remove tactless commentary 2017. Also, the possibility of reducing the misery in factory farming through genetic alteration discussed in this post does not and would not justify factory farming.]
I have spoken with a lot of people who are enthusiastic about the possibility that advanced genetic engineering technologies will improve animal welfare.

But would it really take radical new technologies to produce genetics reducing animal suffering? 

Modern animal breeding is able to shape almost any quantitative trait with significant heritable variation in a population. One carefully measures the trait in different animals, and selects sperm for the next generation on that basis. So far this has not been done to reduce animals' capacity for pain, or to increase their capacity for pleasure, but it has been applied to great effect elsewhere.

One could test varied behavioral measures of fear response, and physiological measures like cortisol levels, and select for them. As long as the measurements in aggregate tracked one's conception of animal welfare closely enough, breeders could generate increases in farmed animal welfare, potentially initially at low marginal cost in other traits.

Just how powerful are ordinary animal breeding techniques? Consider cattle:
In 1942, when my father was born, the average dairy cow produced less than 5,000 pounds of milk in its lifetime. Now, the average cow produces over 21,000 pounds of milk. At the same time, the number of dairy cows has decreased from a high of 25 million around the end of World War II to fewer than nine million today. This is an indisputable environmental win as fewer cows create less methane, a potent greenhouse gas, and require less land.
 Wired has an impressive chart of turkey weight over time:

New_sweet_chart
Anderson, who has bred the birds for 26 years, said the key technical advance was artificial insemination, which came into widespread use in the 1960s, right around the time that turkey size starts to skyrocket...
This process, compounded over dozens of generations, has yielded turkeys with genes that make them very big. In one study in the journal Poultry Science, turkeys genetically representative of old birds from 1966 and modern turkeys were each fed the exact same old-school diet. The 2003 birds grew to 39 pounds while the legacy birds only made it to 21 pounds. Other researchers have estimated that 90 percent of the changes in turkey size are genetic.
Moreover, breeders are able to improve complex weighted mixtures of diverse traits:

Monday, November 05, 2012

Nuclear winter and human extinction: Q&A with Luke Oman


Cross-posted from Overcoming Bias

In Reasons and Persons, philosopher Derek Parfit wrote:
I believe that if we destroy mankind, as we now can, this outcome will be much worse than most people think. Compare three outcomes: 
1. Peace
2. A nuclear war that kills 99% of the world's existing population.
3. A nuclear war that kills 100% 
2 would be worse than 1, and 3 would be worse than 2. Which is the greater of these two differences? Most people believe that the greater difference is between 1 and 2. I believe that the difference between 2 and 3 is very much greater... If we do not destroy mankind, these thousand years may be only a tiny fraction of the whole of civilized human history.
The ethical questions raised by the example have been much discussed, but almost nothing has been written on the empirical question: given nuclear war, how likely is scenario 3?

The most obvious path from nuclear war to human extinction is nuclear winter: past posts on Overcoming Bias have bemoaned neglect of nuclear winter, and high-lighted recent research. Particularly important is a 2007 paper by Alan Robock, Luke Oman, and Georgiy Stenchikov:  "Nuclear winter revisited with a modern climate model and current nuclear arsenals: Still catastrophic consequences." Their model shows severe falls in temperature and insolation that would devastate agriculture and humanity's food supply, with the potential for billions of deaths from famine in addition to the direct damage.

So I asked Luke Oman for his estimate of the risk that nuclear winter would cause human extinction, in addition to its other terrible effects. He gave the following estimate:
The probability I would estimate for the global human population of zero resulting from the 150 Tg of black carbon scenario in our 2007 paper would be in the range of 1 in 10,000 to 1 in 100,000.
I tried to base this estimate on the closest rapid climate change impact analog that I know of, the Toba supervolcanic eruption approximately 70,000 years ago.  There is some suggestion that around the time of Toba there was a population bottleneck in which the global population was severely reduced.  Climate anomalies could be similar in magnitude and duration.  Biggest population impacts would likely be Northern Hemisphere interior continental regions with relatively smaller impacts possible over Southern Hemisphere island nations like New Zealand.
Luke also graciously gave a short Q & A to clarify his reasoning, below the fold:

Monday, September 17, 2012

Spreading happiness to the stars seems little harder than just spreading

Imagine there are two advanced interstellar civilizations near one another who begin outward colonization around the same time, in an otherwise uninhabited accessible universe. One civilization likes to create convert star systems into lots of people leading rich, happy lives full of interest and reward. Call them the Eudaimonians. The other is solely interested in expanding its sphere of colonization as quickly as possible, and produces much less or negative welfare. Call them the Locusts. How much of a competitive advantage do the Locusts have over the Eudaimonians? How much of the cosmic commons, as Robin Hanson calls it, would wind up transformed into worthwhile lives, rather than burned to slightly accelerate colonization efforts? If the Locusts will inevitably capture almost all resources, then little could be done to avert astronomical waste, but an even waste-free split of the accessible universe could be half as good as a Eudaimonic monopoly.

I would argue that in our universe the Eudaimonians will be almost exactly as competitive as the Locusts in rapidly colonizing the stars. The reason is that the Eudaimonians can also adopt a strategy of near-maximum colonization speed until they reach the most distant accessible galaxies, and only then divert resources to producing welfare. More below the fold.

Can catch-up growth take us to the stars?

Will our civilization ever be able to colonize the stars and avert astronomical waste? Will we create computer programs more intelligent and energy-efficient than ourselves, enabling much larger and smarter sapient populations? We don't know exactly how hard it will be to engineer interstellar probes, or build AI, and we probably won't be sure until we actually do so.

However, we can shed some light on the question of whether humanity will ever be able to colonize the stars by asking how existing methods and technologies could increase our capacities, if they were deployed widely and to their limits. Here's a thought experiment: if we imagine that we were magically frozen in roughly our current technological regime for a time, long enough for Malthusian population growth and competition, how much would our economic and scientific production grow? By Malthusian, I mean that population would keep increasing until food costs started to price people out of reproduction, with higher-income folk reproducing more, and institutions that lead to high incomes spreading through migration, imitation or conquest.

Below the fold, I consider several dimensions where existing systems could simply be scaled up to increase global output and R&D: bringing poor countries up to the standards of rich countries, increasing population, and increasing average human capital within countries to near the level of the best-endowed households. Collectively, I estimate they could increase global R&D efforts by more than one hundred fold.

Monday, July 16, 2012

Rawls' original position, potential people, and Pascal's Mugging

tl;dr: If we take possible people into account, even endorsing the Repugnant Conclusion would only provide a negligible chance of getting to exist. So in the Rawlsian original position, they would be concerned with other features of society than population.

Friday, May 11, 2012

What to eat during impact winter?

A number of possible global catastrophic risks seem like they would do their worst damage by disrupting food production. Some examples include nuclear winter, asteroid impacts, and supervolcanoes. In addition to directly laying waste to significant areas, such events would cast ash, dust, or other materials into the atmosphere. Temperatures would fall and solar radiation for primary producers would be reduced, causing agricultural failures and wreaking havoc on wilderness ecologies. It seems clear that feasible events of this sort could cost hundreds of millions or even billions of lives. But would even extreme events actually bring about would they cause human extinction or constitute an existential risk?

There are several sources of evidence we can bring to bear on the question. We can apply the "outside view" and consider the species, including hominids and primates, that have survived past volcanic and asteroid impacts. We can examine current supplies of food sources that could provide for humans during a period of impaired solar radiation. And we can look at past and present social behavior that bears on the distribution of food and recovery from period of severe famine. In the aggregate, it seems to me that humanity would survive one of these severe food disruptions, despite terrible quantities of death and misery.

This post will take a first-pass look at existing food sources that could be drawn upon during a "year without the Sun," or something close to it.