The main reason to be careful when you walk up a flight of stairs is not that you might slip and ... more The main reason to be careful when you walk up a flight of stairs is not that you might slip and have to retrace one step, but rather that the first slip might cause a second slip, and so on until you fall dozens of steps and break your neck. Similarly, we are concerned about the sorts of catastrophes explored in this book not only because of their terrible direct effects, but also because they may induce an even more damaging collapse of our economic and social systems. In this chapter, I consider the nature of societies, the nature of social collapse, and the distribution of disasters that might induce social collapse, and possible strategies for limiting the extent and harm of such collapse. Before we can understand how societies collapse, we must first understand how societies exist and grow. Humans are far more numerous, capable, and rich than were our distant ancestors. How is this possible? One answer is that today we have more of most kinds of ‘capital’, but by itself this a...
According to a hard-steps model of advanced life timing, humans seem puzzlingly early. We offer a... more According to a hard-steps model of advanced life timing, humans seem puzzlingly early. We offer an explanation: an early deadline is set by “grabby” civilizations (GC), who expand rapidly, never die alone, change the appearance of the volumes they control, and who are not born within other GC volumes. If we might soon become grabby, then today is near a sample origin date of such a GC. A selection effect explains why we don’t see them even though they probably control over a third of the universe now. Each parameter in our three parameter model can be estimated to within roughly a factor of four, allowing principled predictions of GC origins, spacing, appearance, and durations till we see or meet them.
If life on Earth had to achieve n “hard steps“ to reach humanity's level, then the chance of ... more If life on Earth had to achieve n “hard steps“ to reach humanity's level, then the chance of this event rose as time to the nth power. Integrating this over habitable star formation and planet lifetime distributions predicts >99% of advanced life appears after today, unless n < 3 and max planet duration <50 Gyr. That is, we seem early. We offer this explanation: a deadline is set by loud aliens who are born according to a hard steps power law, expand at a common rate, change their volume appearances, and prevent advanced life like us from appearing in their volumes. Quiet aliens, in contrast, are much harder to see. We fit this three-parameter model of loud aliens to data: (1) birth power from the number of hard steps seen in Earth’s history, (2) birth constant by assuming a inform distribution over our rank among loud alien birth dates, and (3) expansion speed from our not seeing alien volumes in our sky. We estimate that loud alien civilizations now control 40%–50% of...
We describe algorithms for use by prediction markets in forming a crowd consensus joint probabili... more We describe algorithms for use by prediction markets in forming a crowd consensus joint probability distribution over thousands of related events. Equivalently, we describe market mechanisms to efficiently crowdsource both structure and parameters of a Bayesian network. Prediction markets are among the most accurate methods to combine forecasts; forecasters form a consensus probability distribution by trading contingent securities. A combinatorial prediction market forms a consensus joint distribution over many related events by allowing conditional trades or trades on Boolean combinations of events. Explicitly representing the joint distribution is infeasible, but standard inference algorithms for graphical probability models render it tractable for large numbers of base events. We show how to adapt these algorithms to compute expected assets conditional on a prospective trade, and to find the conditional state where a trader has minimum assets, allowing full asset reuse. We compar...
Hypertext publishing, the integration of a very large body of public writings into a unified hype... more Hypertext publishing, the integration of a very large body of public writings into a unified hypertext environment, will require the simultaneous solution of problems involving very wide database distribution, copyright, freedom of speech, privacy, and information overload. This paper describes these problems and presents, for criticism and discussion, an abstract design called LinkText which seems to solve many of them. LinkText is presented both as a specification and as design approaches grouped around various levels of electronic publishing.
A world product time series covering two million years is well fit by either a sum of four expone... more A world product time series covering two million years is well fit by either a sum of four exponentials, or a constant elasticity of substitution (CES) combination of three exponential growth modes: "hunting," "farming," and "industry." The CES parameters suggest that farming substituted for hunting, while industry complemented farming, making the industrial revolution a smoother transition. Each mode grew world
Humans lie and deceive themselves, and often choose beliefs for reasons other than how closely th... more Humans lie and deceive themselves, and often choose beliefs for reasons other than how closely those beliefs approximate truth. This is mainly why we disagree. Three future trends may reduce these epistemic vices. First, increased documentation and surveillance should make it harder to lie and self-deceive about the patterns of our lives. Second, speculative markets can create a relatively unbiased consensus on most debated topics in science, business, and policy. Third, brain modifications may allow our minds to be more transparent, so that lies and self-deception become harder to hide. In evaluating these trends, we should be wary of moral arrogance.
There is a widespread feeling that health is special; the rules that are usually used in other po... more There is a widespread feeling that health is special; the rules that are usually used in other policy areas are not applied in health policy. Health economists, for example, tend to be reluctant to offer economists' usual prescription of competition and consumer choice, even though they have largely failed to justify this reluctance by showing that health economics involves special features such as public goods, externalities, adverse selection, poor consumer information, or unusually severe consequences.
The main reason to be careful when you walk up a flight of stairs is not that you might slip and ... more The main reason to be careful when you walk up a flight of stairs is not that you might slip and have to retrace one step, but rather that the first slip might cause a second slip, and so on until you fall dozens of steps and break your neck. Similarly, we are concerned about the sorts of catastrophes explored in this book not only because of their terrible direct effects, but also because they may induce an even more damaging collapse of our economic and social systems. In this chapter, I consider the nature of societies, the nature of social collapse, and the distribution of disasters that might induce social collapse, and possible strategies for limiting the extent and harm of such collapse. Before we can understand how societies collapse, we must first understand how societies exist and grow. Humans are far more numerous, capable, and rich than were our distant ancestors. How is this possible? One answer is that today we have more of most kinds of ‘capital’, but by itself this a...
According to a hard-steps model of advanced life timing, humans seem puzzlingly early. We offer a... more According to a hard-steps model of advanced life timing, humans seem puzzlingly early. We offer an explanation: an early deadline is set by “grabby” civilizations (GC), who expand rapidly, never die alone, change the appearance of the volumes they control, and who are not born within other GC volumes. If we might soon become grabby, then today is near a sample origin date of such a GC. A selection effect explains why we don’t see them even though they probably control over a third of the universe now. Each parameter in our three parameter model can be estimated to within roughly a factor of four, allowing principled predictions of GC origins, spacing, appearance, and durations till we see or meet them.
If life on Earth had to achieve n “hard steps“ to reach humanity's level, then the chance of ... more If life on Earth had to achieve n “hard steps“ to reach humanity's level, then the chance of this event rose as time to the nth power. Integrating this over habitable star formation and planet lifetime distributions predicts >99% of advanced life appears after today, unless n < 3 and max planet duration <50 Gyr. That is, we seem early. We offer this explanation: a deadline is set by loud aliens who are born according to a hard steps power law, expand at a common rate, change their volume appearances, and prevent advanced life like us from appearing in their volumes. Quiet aliens, in contrast, are much harder to see. We fit this three-parameter model of loud aliens to data: (1) birth power from the number of hard steps seen in Earth’s history, (2) birth constant by assuming a inform distribution over our rank among loud alien birth dates, and (3) expansion speed from our not seeing alien volumes in our sky. We estimate that loud alien civilizations now control 40%–50% of...
We describe algorithms for use by prediction markets in forming a crowd consensus joint probabili... more We describe algorithms for use by prediction markets in forming a crowd consensus joint probability distribution over thousands of related events. Equivalently, we describe market mechanisms to efficiently crowdsource both structure and parameters of a Bayesian network. Prediction markets are among the most accurate methods to combine forecasts; forecasters form a consensus probability distribution by trading contingent securities. A combinatorial prediction market forms a consensus joint distribution over many related events by allowing conditional trades or trades on Boolean combinations of events. Explicitly representing the joint distribution is infeasible, but standard inference algorithms for graphical probability models render it tractable for large numbers of base events. We show how to adapt these algorithms to compute expected assets conditional on a prospective trade, and to find the conditional state where a trader has minimum assets, allowing full asset reuse. We compar...
Hypertext publishing, the integration of a very large body of public writings into a unified hype... more Hypertext publishing, the integration of a very large body of public writings into a unified hypertext environment, will require the simultaneous solution of problems involving very wide database distribution, copyright, freedom of speech, privacy, and information overload. This paper describes these problems and presents, for criticism and discussion, an abstract design called LinkText which seems to solve many of them. LinkText is presented both as a specification and as design approaches grouped around various levels of electronic publishing.
A world product time series covering two million years is well fit by either a sum of four expone... more A world product time series covering two million years is well fit by either a sum of four exponentials, or a constant elasticity of substitution (CES) combination of three exponential growth modes: "hunting," "farming," and "industry." The CES parameters suggest that farming substituted for hunting, while industry complemented farming, making the industrial revolution a smoother transition. Each mode grew world
Humans lie and deceive themselves, and often choose beliefs for reasons other than how closely th... more Humans lie and deceive themselves, and often choose beliefs for reasons other than how closely those beliefs approximate truth. This is mainly why we disagree. Three future trends may reduce these epistemic vices. First, increased documentation and surveillance should make it harder to lie and self-deceive about the patterns of our lives. Second, speculative markets can create a relatively unbiased consensus on most debated topics in science, business, and policy. Third, brain modifications may allow our minds to be more transparent, so that lies and self-deception become harder to hide. In evaluating these trends, we should be wary of moral arrogance.
There is a widespread feeling that health is special; the rules that are usually used in other po... more There is a widespread feeling that health is special; the rules that are usually used in other policy areas are not applied in health policy. Health economists, for example, tend to be reluctant to offer economists' usual prescription of competition and consumer choice, even though they have largely failed to justify this reluctance by showing that health economics involves special features such as public goods, externalities, adverse selection, poor consumer information, or unusually severe consequences.
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Papers by Robin Hanson