This is a section-by-section summary and review of Sapiens: A Brief History of Humankind by Yuval Noah Harari. It's come up on Less Wrong before in the context of Death is Optional, a conversation the author had with Daniel Kahneman about the book, and seems like an accessible introduction to many of the concepts underlying the LW perspective on history and the future. Anyone who's thought about Moloch will find many of the same issues discussed here, and so I'll scatter links to Yvain throughout. I'll discuss several of the points that I thought were interesting and novel, or at least had a novel perspective and good presentation.

A history as expansive as this one necessarily involves operating on higher levels of abstraction. The first section expresses this concisely enough to quote in full:

About 13.5 billion years ago, matter, energy, time and space came into being in what is known as the Big Bang. The story of these fundamental features of our universe is called physics.

About 300,000 years after their appearance, matter and energy started to coalesce into complex structures, called atoms, which then combined into molecules. The story of atoms, molecules and their interactions is called chemistry.

About 3.8. billion years ago, on a planet called Earth, certain molecules combined to form particularly large and intricate structures called organisms. The story of organisms is called biology.

About 70,000 years ago, organisms belonging to the species Homo sapiens started to form even more elaborate structures called cultures. The subsequent development of these human cultures is called history.

Three important revolutions shaped the course of history: the Cognitive Revolution kick-started history about 70,000 years ago. The Agricultural Revolution sped it up about 12,000 years ago. The Scientific Revolution, which got under way only 500 years ago, may well end history and start something completely different. This book tells the story of how these three revolutions have affected humans and their fellow organisms.

This is a summary of the customs for collaborative writing the team on the fanfiction In Fire Forged came to, after a fair amount of time and effort figuring things out. The purpose of this piece is to share our results, thereby saving anyone who wants to write collaboratively the cost of experimentation. Obviously, different writing projects will accomplish different things with different people, and will therefore be best served by different practices. Take this as a first approximation, to be revised by experience.

Google Docs

We tried a bunch of platforms for collaboration, and found Google Docs to best fit our needs.

1. Create a Google Doc. Multi-installment affairs may consider creating a folder and make one doc per installment.
2. Enable editing. Collaborators are not very helpful if they can't provide feedback.
   
   Google Docs allows authors to restrict the changes other people can make to "suggestions" and "comments" by switching to "suggesting" mode.
   
   
   
   In general, the author restricts collaborator permissions to comments and suggestions. How to control these permissions should be described in the "enable editing" link above.

3. Distribute link to collaborators.

Once the collaborators have the link, they read through it, making the comments and suggestions they think of. Google Docs does a good job facilitating discussion of this feedback; utilize this!

Micro and Macro

We found it useful to distinguish between what we were saying and how we were saying it. We termed the former "macro" and the latter "micro". This allows authors to say things like "I'm mostly looking for micro suggestions, although I'd be interested in any glaring macro errors (anything untrue or major omissions)." This succinctly communicates that collaborators should mostly restrict themselves to suggesting changes to how the author is communicating, which usually consists of small edits concerning things like technical issues (typos, omitted words, grammar) and smoother communication (word choice, resolving ambiguities, sectioning).

This contrasts macro suggestions, which would include (in nonfiction) things like making sure factual claims were true, being sure to include all relevant information, and the perspective from a different field. (In fiction, macro suggestions would include things such as plot, characterization, chapter structure and consistency of the universe.)

In general, you want to address macro issues before micro issues, since micro improvements are lost to changes on the macro level.

Team Makeup

On the macro level, you want as many people as can bring novel, relevant viewpoints to the writing. Essentially, you're looking to exploit Linus's Law by having at least one collaborator who will naturally see every improvement that could be made.

I favor erring on the size of larger teams for a few reasons. The coordination cost of adding a member isn't very high. Improving things on the micro level really benefits from having lots of eyeballs scrutinize for improvements: it's entirely plausible that the tenth reader of some passage notices a way to reword it that the first nine missed.

My favorite reason for having more collaborators, however, is that it opens up the possibility of partial editing. One collaborator flags something they notice could be improved, even if they can't think of how. Then, another collaborator, who may not have noticed that something sounded awkward, may figure out how to rewrite it better. (It may sound implausible that someone who can figure out the improvement wouldn't notice something improvable in the first place, but it happened reasonably often.)

Spreading the micro over a lot of people also helps avoid illusions of transparency. If you only have one or two people revising, it's easy for them to spend so much time that they miss statements that don't mean what they think it means or are ambiguous, since they're so familiar with what they mean to mean. Spreading out the editing keeps everyone from becoming overfamiliar with the work. It also allows for holding editors in reverse, who give the work one last pass and read it as naively as the target audience.

Collaborator Benefits

Helping someone else write their piece is the single most effective technique I've used to powerlevel my writing. SICP:

The ability to visualize the consequences of the actions under consideration is crucial to becoming an expert programmer, just as it is in any synthetic, creative activity. In becoming an expert photographer, for example, one must learn how to look at a scene and know how dark each region will appear on a print for each possible choice of exposure and development conditions. Only then can one reason backward, planning framing, lighting, exposure, and development to obtain the desired effects. So it is with programming...

...and so it is with writing. There's an awkward period when you're first starting to write, where you've read enough that you have some idea of what better and worse writing looks like, but you haven't written enough to visualize the consequences of your writing. The author of In Fire Forged got there by writing and scrapping 140k words. I got there with a fraction of the effort by helping out on a team that allowed me to see the consequences of various actions without needing to write entire pieces. I also got to see and analyze and discuss the feedback from the other collaborators, which taught me things about better writing I didn't already know. Plus, gaining this experience had positive externalities, since the suggestions I made wound up in a final product, instead of going into the trash.

Collaborating also helps you learn about the topic of the piece more effectively than just reading it, via levels of processing. Merely reading about something is fairly shallow, leading to nondurable memory, whereas collaborating on something forces deeper processing, and thus more durable understanding. You can force yourself to process something on a deeper level as you read it to get the same effect, but collaborating, again, produces positive externalities.

(You should be processing deeply anyway. One collaborator on this piece, for instance, puts comments in the margins of pieces she reads. That said, collaborating has positive externalities.)

It's also fun and social; writing collaboratively has caused me to meet some of my favorite people and strengthened many personal relationships. As such, I suggest that, should you come across some piece that you take a liking to, but see how you could improve it, you offer to collaborate with them. Worst case, they're flattered and turn you down politely.

A paper published in Astrobiology: A New Empirical Constraint on the Prevalence of Technological Species in the Universe (PDF), A. Frank and W.T. Sullivan.

From the abstract:

Recent advances in exoplanet studies provide strong constraints on all astrophysical terms in the Drake equation. [...] We find that as long as the probability that a habitable zone planet develops a technological species is larger than ~ 10^-24, humanity is not the only time technological intelligence has evolved.

They say we now know with reasonable certainty the total number of stars ever to exist (in the observable universe), and the average number of planets in the habitable zone. But we still don't know the probabilities of life, intelligence, and technology arising. They call this cumulative unknown factor f_bt.

Their result: for technological civilization to arise no more than once, with probability 0.01, in the lifetime of the observable universe, f_bt should be no greater than ~ 2.5 x 10^-24.

Discussion

It's convenient that they calculate the chance technological civilization ever arose, rather than the chance one exists now. This is just the number we need to estimate the likelihood of a Great Filter.

They state their result as "[if we set f_bt ≤ 2.5 x 10^-24, then] at in a statistical sense were we to rerun the history of the Universe 100 times, only once would a lone technological species occur". But I don't know what rerunning the Universe means. I also can't formulate this as saying "if we hadn't already observed the Universe to be apparently empty of life, we would expect it to contain or to have once contained life with a probability of 10²⁴", because that would ignore the chance that another civilization (if it counterfactually existed) would have affected or prevented the rise of life on Earth. Can someone help reformulate this? 

I don't know if their modern values for star and planet formation have been used in previous discussions of the Fermi paradox or the Great Filter. (The papers they cite for their values date from 2012, 2013 and 2015.) I also don't know if these values should be trusted, or what concrete values had been used previously. People on top of the Great Filter discussion probably already updated when the astronomical data came in.

Related to: The Correct Contrarian Cluster, The General Factor of Correctness

(Content note: Explicitly about spreading rationalist memes, increasing the size of the rationalist movement, and proselytizing. I also regularly use the word 'we' to refer to the rationalist community/subculture. You might prefer not to read this if you don't like that sort of thing and/or you don't think I'm qualified to write about that sort of thing and/or you're not interested in providing constructive criticism.)

I've tried to introduce a number of people to this culture and the ideas within it, but it takes some finesse to get a random individual from the world population to keep thinking about these things and apply them. My personal efforts have been very hit-or-miss. Others have told me that they've been more successful. But I think there are many people that share my experience. This is unfortunate: we want people to be more rational and we want more rational people.

At any rate, this is not about the art of raising the sanity waterline, but the more general task of spreading rationalist memes. Some people naturally arrive at these ideas, but they usually have to find them through other people first. This is really about all of the people in the world who are like you probably were before you found this culture; the people who would care about it, and invest in it, as it is right now, if only they knew it existed.

I'm going to be vague for the sake of anonymity, but here it goes:

I was reading a book review on Amazon, and I really liked it. The writer felt like a kindred spirit. I immediately saw that they were capable of coming to non-obvious conclusions, so I kept reading. Then I checked their review history in the hope that I would find other good books and reviews. And it was very strange.

They did a bunch of stuff that very few humans do. They realized that nuclear power has risks but that the benefits heavily outweigh the risks given the appropriate alternative, and they realized that humans overestimate the risks of nuclear power for silly reasons. They noticed when people were getting confused about labels and pointed out the general mistake, as well as pointing out what everyone should really be talking about. They acknowledged individual and average IQ differences and realized the correct policy implications. They really understood evolution, they took evolutionary psychology seriously, and they didn't care if it was labeled as sociobiology. They used the word 'numerate.'

And the reviews ranged over more than a decade of time. These were persistent interests.

I don't know what other people do when they discover that a stranger like this exists, but the first thing that I try to do is talk to them. It's not like I'm going to run into them on the sidewalk.

Amazon had no messaging feature that I could find, so I looked for a website, and I found one. I found even more evidence, and that's certainly what it was. They were interested in altruism, including how it goes wrong; computer science; statistics; psychology; ethics; coordination failures; failures of academic and scientific institutions; educational reform; cryptocurrency, etc. At this point I considered it more likely than not that they already knew everything that I wanted to tell them, and that they already self-identified as a rationalist, or that they had a contrarian reason for not identifying as such.

So I found their email address. I told them that they were a great reviewer, that I was surprised that they had come to so many correct contrarian conclusions, and that, if they didn't already know, there was a whole culture of people like them.

They replied in ten minutes. They were busy, but they liked what I had to say, and as a matter of fact, a friend had already convinced them to buy Rationality: From AI to Zombies. They said they hadn't read much relative to the size of the book because it's so large, but they loved it so far and they wanted to keep reading.

(You might postulate that I found a review by a user like this on a different book because I was recommended this book and both of us were interested in Rationality: From AI to Zombies. However, the first review I read by this user was for a book on unusual gardening methods, that I found in a search for books about gardening methods. For the sake of anonymity, however, my unusual gardening methods must remain a secret. It is reasonable to postulate that there would be some sort of sampling bias like the one that I have described, but given what I know, it is likely that this is not that. You certainly could still postulate a correlation by means of books about unusual gardening methods, however.)

Maybe that extra push made the difference. Maybe if there hadn't been a friend, I would've made the difference.

Who knew that's how my morning would turn out?

As I've said in some of my other posts, but not in so many words, maybe we should start doing this accidentally effective thing deliberately!

I know there's probably controversy about whether or not rationalists should proselytize, but I've been in favor of it for awhile. And if you're like me, then I don't think this is a very special effort to make. I'm sure sometimes you see a little thread, and you think, "Wow, they're a lot like me; they're a lot like us, in fact; I wonder if there are other things too. I wonder if they would care about this."

Don't just move on! That's Bayesian evidence!

I dare you to follow that path to its destination. I dare you to reach out. It doesn't cost much.

And obviously there are ways to make yourself look creepy or weird or crazy. But I said to reach out, not to reach out badly. If you could figure out how to do it right, it could have a large impact. And these people are likely to be pretty reasonable. You should keep a look out in the future.

Speaking of the future, it's worth noting that I ended up reading the first review because of an automated Amazon book recommendation and subsequent curiosity. You know we're in the data. We are out there and there are ways to find us. In a sense, we aren't exactly low-hanging fruit. But in another sense, we are.

I've never read a word of the Methods of Rationality, but I have to shoehorn this in: we need to write the program that sends a Hogwarts acceptance letter to witches and wizards on their eleventh birthday.

One or two research groups have published work on carbon dioxide and cognition. The state of the published literature is confusing.

Here is one paper on the topic. The authors investigate a proprietary cognitive benchmark, and experimentally manipulate carbon dioxide levels (without affecting other measures of air quality). They find implausibly large effects from increased carbon dioxide concentrations.

If the reported effects are real and the suggested interpretation is correct, I think it would be a big deal. To put this in perspective, carbon dioxide concentrations in my room vary between 500 and 1500 ppm depending on whether I open the windows. The experiment reports on cognitive effects for moving from 600 and 1000 ppm, and finds significant effects compared to interindividual differences.

I haven't spent much time looking into this (maybe 30 minutes, and another 30 minutes to write this post). I expect that if we spent some time looking into indoor CO2 we could have a much better sense of what was going on, by some combination of better literature review, discussion with experts, looking into the benchmark they used, and just generally thinking about it.

So, here's a proposal:

• If someone looks into this and writes a post that improves our collective understanding of the issue, I will be willing to buy part of an associated certificate of impact, at a price of around $100*N, where N is my own totally made up estimate of how many hours of my own time it would take to produce a similarly useful writeup. I'd buy up to 50% of the certificate at that price.
• Whether or not they want to sell me some of the certificate, on May 1 I'll give a $500 prize to the author of the best publicly-available analysis of the issue. If the best analysis draws heavily on someone else's work, I'll use my discretion: I may split the prize arbitrarily, and may give it to the earlier post even if it is not quite as excellent.

Some clarifications:

• The metric for quality is "how useful it is to Paul." I hope that's a useful proxy for how useful it is in general, but no guarantees. I am generally a pretty skeptical person. I would care a lot about even a modest but well-established effect on performance. 
• These don't need to be new analyses, either for the prize or the purchase.
• I reserve the right to resolve all ambiguities arbitrarily, and in the end to do whatever I feel like. But I promise I am generally a nice guy.
• I posted this 2 weeks ago on the EA forum and haven't had serious takers yet.