Rational Toothpaste: A Case Study

68 badger 31 May 2012 12:31AM

Inspired by Konkvistador's comment

Posts titled "Rational ___-ing" or "A Rational Approach to ____" induce groans among a sizeable contingent here, myself included. However, inflationary use of "rational" and its transformation into an applause light is only one part of the problem. These posts tend to revolve around specific answers, rather than the process of how to find answers. I claim a post on "rational toothpaste buying" could be on-topic and useful, if correctly written to illustrate determining goals, assessing tradeoffs, and implementing the final conclusions. A post detailing the pros and cons of various toothpaste brands is for a dentistry or personal hygiene forum; a post about algorithms for how to determine the best brands or whether to do so at all is for a rationality forum. This post is my shot at showing what this would look like.

continue reading »

Holden's Objection 1: Friendliness is dangerous

11 PhilGoetz 18 May 2012 12:48AM

Nick_Beckstead asked me to link to posts I referred to in this comment.  I should put up or shut up, so here's an attempt to give an organized overview of them.

Since I wrote these, LukeProg has begun tackling some related issues.  He has accomplished the seemingly-impossible task of writing many long, substantive posts none of which I recall disagreeing with.  And I have, irrationally, not read most of his posts.  So he may have dealt with more of these same issues.

I think that I only raised Holden's "objection 2" in comments, which I couldn't easily dig up; and in a critique of a book chapter, which I emailed to LukeProg and did not post to LessWrong.  So I'm only going to talk about "Objection 1:  It seems to me that any AGI that was set to maximize a "Friendly" utility function would be extraordinarily dangerous."  I've arranged my previous posts and comments on this point into categories.  (Much of what I've said on the topic has been in comments on LessWrong and Overcoming Bias, and in email lists including SL4, and isn't here.)

 

The concept of "human values" cannot be defined in the way that FAI presupposes

Human errors, human values:  Suppose all humans shared an identical set of values, preferences, and biases.  We cannot retain human values without retaining human errors, because there is no principled distinction between them.

A comment on this post:  There are at least three distinct levels of human values:  The values an evolutionary agent holds that maximize their reproductive fitness, the values a society holds that maximizes its fitness, and the values a rational optimizer holds who has chosen to maximize social utility.  They often conflict.  Which of them are the real human values?

Values vs. parameters:  Eliezer has suggested using human values, but without time discounting (= changing the time-discounting parameter).  CEV presupposes that we can abstract human values and apply them in a different situation that has different parameters.  But the parameters are values.  There is no distinction between parameters and values.

A comment on "Incremental progress and the valley":  The "values" that our brains try to maximize in the short run are designed to maximize different values for our bodies in the long run.  Which are human values:  The motivations we feel, or the effects they have in the long term?  LukeProg's post Do Humans Want Things? makes a related point.

Group selection update:  The reason I harp on group selection, besides my outrage at the way it's been treated for the past 50 years, is that group selection implies that some human values evolved at the group level, not at the level of the individual.  This means that increasing the rationality of individuals may enable people to act more effectively in their own interests, rather than in the group's interest, and thus diminish the degree to which humans embody human values.  Identifying the values embodied in individual humans - supposing we could do so - would still not arrive at human values.  Transferring human values to a post-human world, which might contain groups at many different levels of a hierarchy, would be problematic.

I wanted to write about my opinion that human values can't be divided into final values and instrumental values, the way discussion of FAI presumes they can.  This is an idea that comes from mathematics, symbolic logic, and classical AI.  A symbolic approach would probably make proving safety easier.  But human brains don't work that way.  You can and do change your values over time, because you don't really have terminal values.

Strictly speaking, it is impossible for an agent whose goals are all indexical goals describing states involving itself to have preferences about a situation in which it does not exist.  Those of you who are operating under the assumption that we are maximizing a utility function with evolved terminal goals, should I think admit these terminal goals all involve either ourselves, or our genes.  If they involve ourselves, then utility functions based on these goals cannot even be computed once we die.  If they involve our genes, they they are goals that our bodies are pursuing, that we call errors, not goals, when we the conscious agent inside our bodies evaluate them.  In either case, there is no logical reason for us to wish to maximize some utility function based on these after our own deaths.  Any action I wish to take regarding the distant future necessarily presupposes that the entire SIAI approach to goals is wrong.

My view, under which it does make sense for me to say I have preferences about the distant future, is that my mind has learned "values" that are not symbols, but analog numbers distributed among neurons.  As described in "Only humans can have human values", these values do not exist in a hierarchy with some at the bottom and some on the top, but in a recurrent network which does not have a top or a bottom, because the different parts of the network developed simultaneously.  These values therefore can't be categorized into instrumental or terminal.  They can include very abstract values that don't need to refer specifically to me, because other values elsewhere in the network do refer to me, and this will ensure that actions I finally execute incorporating those values are also influenced by my other values that do talk about me.

Even if human values existed, it would be pointless to preserve them

Only humans can have human values:

  • The only preferences that can be unambiguously determined are the preferences a person (mind+body) implements, which are not always the preferences expressed by their beliefs.
  • If you extract a set of consciously-believed propositions from an existing agent, then build a new agent to use those propositions in a different environment, with an "improved" logic, you can't claim that it has the same values, since it will behave differently.
  • Values exist in a network of other values.  A key ethical question is to what degree values are referential (meaning they can be tested against something outside that network); or non-referential (and hence relative).
  • Supposing that values are referential helps only by telling you to ignore human values.
  • You cannot resolve the problem by combining information from different behaviors, because the needed information is missing.
  • Today's ethical disagreements are largely the result of attempting to extrapolate ancestral human values into a changing world.
  • The future will thus be ethically contentious even if we accurately characterize and agree on present human values, because these values will fail to address the new important problems.


Human values differ as much as values can differ:  There are two fundamentally different categories of values:

  • Non-positional, mutually-satisfiable values (physical luxury, for instance)
  • Positional, zero-sum social values, such as wanting to be the alpha male or the homecoming queen

All mutually-satisfiable values have more in common with each other than they do with any non-mutually-satisfiable values, because mutually-satisfiable values are compatible with social harmony and non-problematic utility maximization, while non- mutually-satisfiable values require eternal conflict.  If you find an alien life form from a distant galaxy with non-positional values, it would be easier to integrate those values into a human culture with only human non-positional values, than to integrate already-existing positional human values into that culture.

It appears that some humans have mainly the one type, while other humans have mainly the other type.  So talking about trying to preserve human values is pointless - the values held by different humans have already passed the most-important point of divergence.

 

Enforcing human values would be harmful

The human problem:  This argues that the qualia and values we have now are only the beginning of those that could evolve in the universe, and that ensuring that we maximize human values - or any existing value set - from now on, will stop this process in its tracks, and prevent anything better from ever evolving.  This is the most-important objection of all.

Re-reading this, I see that the critical paragraph is painfully obscure, as if written by Kant; but it summarizes the argument: "Once the initial symbol set has been chosen, the semantics must be set in stone for the judging function to be "safe" for preserving value; this means that any new symbols must be defined completely in terms of already-existing symbols.  Because fine-grained sensory information has been lost, new developments in consciousness might not be detectable in the symbolic representation after the abstraction process.  If they are detectable via statistical correlations between existing concepts, they will be difficult to reify parsimoniously as a composite of existing symbols.  Not using a theory of phenomenology means that no effort is being made to look for such new developments, making their detection and reification even more unlikely.  And an evaluation based on already-developed values and qualia means that even if they could be found, new ones would not improve the score.  Competition for high scores on the existing function, plus lack of selection for components orthogonal to that function, will ensure that no such new developments last."

Averaging value systems is worse than choosing one:  This describes a neural-network that encodes preferences, and takes some input pattern and computes a new pattern that optimizes these preferences.  Such a system is taken as analogous for a value system and an ethical system to attain those values.  I then define a measure for the internal conflict produced by a set of values, and show that a system built by averaging together the parameters from many different systems will have higher internal conflict than any of the systems that were averaged together to produce it.  The point is that the CEV plan of "averaging together" human values will result in a set of values that is worse (more self-contradictory) than any of the value systems it was derived from.


A point I may not have made in these posts, but made in comments, is that the majority of humans today think that women should not have full rights, homosexuals should be killed or at least severely persecuted, and nerds should be given wedgies.  These are not incompletely-extrapolated values that will change with more information; they are values.  Opponents of gay marriage make it clear that they do not object to gay marriage based on a long-range utilitarian calculation; they directly value not allowing gays to marry.  Many human values horrify most people on this list, so they shouldn't be trying to preserve them.

Thoughts on the Singularity Institute (SI)

256 HoldenKarnofsky 11 May 2012 04:31AM

This post presents thoughts on the Singularity Institute from Holden Karnofsky, Co-Executive Director of GiveWell. Note: Luke Muehlhauser, the Executive Director of the Singularity Institute, reviewed a draft of this post, and commented: "I do generally agree that your complaints are either correct (especially re: past organizational competence) or incorrect but not addressed by SI in clear argumentative writing (this includes the part on 'tool' AI). I am working to address both categories of issues." I take Luke's comment to be a significant mark in SI's favor, because it indicates an explicit recognition of the problems I raise, and thus increases my estimate of the likelihood that SI will work to address them.

September 2012 update: responses have been posted by Luke and Eliezer (and I have responded in the comments of their posts). I have also added acknowledgements.

The Singularity Institute (SI) is a charity that GiveWell has been repeatedly asked to evaluate. In the past, SI has been outside our scope (as we were focused on specific areas such as international aid). With GiveWell Labs we are open to any giving opportunity, no matter what form and what sector, but we still do not currently plan to recommend SI; given the amount of interest some of our audience has expressed, I feel it is important to explain why. Our views, of course, remain open to change. (Note: I am posting this only to Less Wrong, not to the GiveWell Blog, because I believe that everyone who would be interested in this post will see it here.)

I am currently the GiveWell staff member who has put the most time and effort into engaging with and evaluating SI. Other GiveWell staff currently agree with my bottom-line view that we should not recommend SI, but this does not mean they have engaged with each of my specific arguments. Therefore, while the lack of recommendation of SI is something that GiveWell stands behind, the specific arguments in this post should be attributed only to me, not to GiveWell.

Summary of my views

  • The argument advanced by SI for why the work it's doing is beneficial and important seems both wrong and poorly argued to me. My sense at the moment is that the arguments SI is making would, if accepted, increase rather than decrease the risk of an AI-related catastrophe. More
  • SI has, or has had, multiple properties that I associate with ineffective organizations, and I do not see any specific evidence that its personnel/organization are well-suited to the tasks it has set for itself. More
  • A common argument for giving to SI is that "even an infinitesimal chance that it is right" would be sufficient given the stakes. I have written previously about why I reject this reasoning; in addition, prominent SI representatives seem to reject this particular argument as well (i.e., they believe that one should support SI only if one believes it is a strong organization making strong arguments). More
  • My sense is that at this point, given SI's current financial state, withholding funds from SI is likely better for its mission than donating to it. (I would not take this view to the furthest extreme; the argument that SI should have some funding seems stronger to me than the argument that it should have as much as it currently has.)
  • I find existential risk reduction to be a fairly promising area for philanthropy, and plan to investigate it further. More
  • There are many things that could happen that would cause me to revise my view on SI. However, I do not plan to respond to all comment responses to this post. (Given the volume of responses we may receive, I may not be able to even read all the comments on this post.) I do not believe these two statements are inconsistent, and I lay out paths for getting me to change my mind that are likely to work better than posting comments. (Of course I encourage people to post comments; I'm just noting in advance that this action, alone, doesn't guarantee that I will consider your argument.) More

Intent of this post

I did not write this post with the purpose of "hurting" SI. Rather, I wrote it in the hopes that one of these three things (or some combination) will happen:

  1. New arguments are raised that cause me to change my mind and recognize SI as an outstanding giving opportunity. If this happens I will likely attempt to raise more money for SI (most likely by discussing it with other GiveWell staff and collectively considering a GiveWell Labs recommendation).
  2. SI concedes that my objections are valid and increases its determination to address them. A few years from now, SI is a better organization and more effective in its mission.
  3. SI can't or won't make changes, and SI's supporters feel my objections are valid, so SI loses some support, freeing up resources for other approaches to doing good.

Which one of these occurs will hopefully be driven primarily by the merits of the different arguments raised. Because of this, I think that whatever happens as a result of my post will be positive for SI's mission, whether or not it is positive for SI as an organization. I believe that most of SI's supporters and advocates care more about the former than about the latter, and that this attitude is far too rare in the nonprofit world.

continue reading »

Characterizing the superintelligence which we are concerned about

9 JoshuaFox 01 April 2012 06:40PM

What is this “superintelligence” we are concerned about? In writing articles on FAI topics, I took the easy way out and defined the focus of attention as an AI that can far outdo humans in all areas. But this just a useful shortcut, not what we are really talking about.

In this essay, I will try to better rcharacterize the topic of interest.

Some possibilities that have been brought up include intelligences

  • which are human-like,
  • which are conscious,
  • which can outperform humans in some or all areas,
  • which can self-improve,
  • or which meet a semi-formal or formal definition of intelligence or of above-human intelligence.


All these are important features in possible future AIs which we should be thinking about.But what really counts is whether an AI can outwit us when its goals are pitted against ours.

1. Human-like intelligence. We are humans, we care about human welfare; and humans are the primary intelligence which cooperates and competes with us; so human intelligence is our primary model.  Machines that “think like humans” are an intuitive focus on discussions of AI; Turing took this as the basis for his practical test for intelligence

Future AIs might have exactly this type of intelligence, particularly if they are emulated brains, what Robin Hanson calls “ems.”

If human-like AI is the only AI to come, then not much will have happened: We already have seven billion humans, and a few more will simply extend economic trends. If, as Hanson describes, the ems need fewer resources than humans, then we can expect extreme economic impact. If such AI has certain differences from us humans, like the ability to self-improve, then it will fall under the other categories, as described below.

continue reading »

A Crash Course in the Neuroscience of Human Motivation

119 lukeprog 19 August 2011 09:15PM

[PDF of this article updated Aug. 23, 2011]

[skip to preface]

Whenever I write a new article for Less Wrong, I'm pulled in two opposite directions.

One force pulls me toward writing short, exciting posts with lots of brain candy and just one main point. Eliezer has done that kind of thing very well many times: see Making Beliefs Pay Rent, Hindsight Devalues Science, Probability is in the MindTaboo Your Words, Mind Projection FallacyGuessing the Teacher's Password, Hold Off on Proposing Solutions, Applause Lights, Dissolving the Question, and many more.

Another force pulls me toward writing long, factually dense posts that fill in as many of the pieces of a particular argument in one fell swoop as possible. This is largely because I want to write about the cutting edge of human knowledge but I keep realizing that the inferential gap is larger than I had anticipated, and I want to fill in that inferential gap quickly so I can get to the cutting edge.

For example, I had to draw on dozens of Eliezer's posts just to say I was heading toward my metaethics sequence. I've also published 21 new posts (many of them quite long and heavily researched) written specifically because I need to refer to them in my metaethics sequence.1 I tried to make these posts interesting and useful on their own, but my primary motivation for writing them was that I need them for my metaethics sequence.

And now I've written only four posts2 in my metaethics sequence and already the inferential gap to my next post in that sequence is huge again. :(

So I'd like to try an experiment. I won't do it often, but I want to try it at least once. Instead of writing 20 more short posts between now and the next post in my metaethics sequence, I'll attempt to fill in a big chunk of the inferential gap to my next metaethics post in one fell swoop by writing a long tutorial post (a la Eliezer's tutorials on Bayes' Theorem and technical explanation).3

So if you're not up for a 20-page tutorial on human motivation, this post isn't for you, but I hope you're glad I bothered to write it for the sake of others. If you are in the mood for a 20-page tutorial on human motivation, please proceed.

continue reading »

What are you working on?

8 jsalvatier 15 August 2011 02:43PM

This is the fourth bimonthly What Are You Working On? thread. Thanks to atucker for reminding me to make this post. Click here to see previous threads. So here's the question:

What are you working on? 

Here are some guidelines:

  • Focus on projects that you have recently made progress on, not projects that you're thinking about doing but haven't started, those are for a different thread. 
  • Why this project and not others? Mention reasons why you're doing the project and/or why others should contribute to your project (if applicable).
  • Talk about your goals for the project.
  • Any kind of project is fair game: personal improvement, research project, art project, whatever.
  • Link to your work if it's linkable.

Build Small Skills in the Right Order

90 lukeprog 17 April 2011 11:01PM

I took some Scientology classes in Hollywood so I could get into their Toastmasters club, which is the best Toastmasters club in L.A. county.1 My first Scientology class, 'Success Through Communication', taught skills that were mostly non-specific to Scientology. At first, the class exercises seemed to teach skills too basic to be worth practicing. Later, I came to respect the class as surprisingly useful. (But please, don't take Scientology classes. They are highly Dark Arts, and extremely manipulative.)

For the first exercise, I had to sit upright, still, and silent with my eyes closed for about an hour. I was to remain alert and aware but utterly calm. When my head drooped or my hand twitched, I was forced to start over. It took me five hours of silent sitting to complete the exercise successfully. At first I thought the exercise was stupid, but later I found I was now more in control of my awareness and attention, and less disturbed by things in the environment.

For the second exercise, I had to stare directly into someone's eyes without looking away - even for a split second - for 20 minutes in a row. If you've never tried this, you should. It's very difficult. Unfortunately, they first paired me with a 12-year-old girl. I was sure I would freak her out if I stared into her eyes for 20 minutes (it's an intense experience), so I made faces when the instructors weren't looking and waited for them to pair me with an adult. After half a dozen failures, I finally managed to maintain eye contact for 20 minutes in a row, without a single glance away or a long blink.

Again, this seemed absurd at the time, but later I discovered that I no longer had any trouble maintaining eye contact with people. This skill is a small one, but it is highly valuable in almost every social endeavor.

Later exercises seemed childish. An instructor would ask me simple questions from a book like, "What's that over there?" and I would have to answer correctly: "That's a table." I had to do this for hundreds of questions. But I couldn't just say "That's a table" any old way. I had to say it without a stutter, I had to enunciate, and I had to speak loudly. Answering questions like this 100 times in a row will reveal how often most of us speak softly, fail to enunciate, and use filler words like "um." Every time I did one of those things, I had to start over.

In another exercise, the instructor would do everything she could to make me laugh, and I had to sit still and not crack a hint of a smile for 10 minutes in a row. This simple skill took many rounds to master. It is a small skill, but repeating a simple exercise like this will eventually bring almost anyone to mastery of this small skill. At the end of the exercise I had noticeably improved a small part of my self-control mechanism.

This class - a religious class I took as an atheist in order to achieve an unrelated goal - turned out to be one of the most important classes I have ever taken in my life. It taught me an important meta-skill I have used to great effect ever since.

This is the meta-skill of building small skills in the right order. It is now one of the key tools in my toolkit for instrumental rationality.

continue reading »

The Neglected Virtue of Scholarship

177 lukeprog 05 January 2011 07:22AM

Eliezer Yudkowsky identifies scholarship as one of the Twelve Virtues of Rationality:

Study many sciences and absorb their power as your own. Each field that you consume makes you larger... It is especially important to eat math and science which impinges upon rationality: Evolutionary psychology, heuristics and biases, social psychology, probability theory, decision theory. But these cannot be the only fields you study...

I think he's right, and I think scholarship doesn't get enough praise - even on Less Wrong, where it is regularly encouraged.

First, consider the evangelical atheist community to which I belong. There is a tendency for lay atheists to write "refutations" of theism without first doing a modicum of research on the current state of the arguments. This can get atheists into trouble when they go toe-to-toe with a theist who did do his homework. I'll share two examples:

  • In a debate with theist Bill Craig, agnostic Bart Ehrman paraphrased David Hume's argument that we can't demonstrate the occurrence of a miracle in the past. Craig responded with a PowerPoint slide showing Bayes' Theorem, and explained that Ehrman was only considering prior probabilities, when of course he needed to consider the relevant conditional probabilities as well. Ehrman failed to respond to this, and looked as though he had never seen Bayes' Theorem before. Had Ehrman practiced the virtue of scholarship on this issue, he might have noticed that much of the scholarly work on Hume's argument in the past two decades has involved Bayes' Theorem. He might also have discovered that the correct response to Craig's use of Bayes' Theorem can be found in pages 298-341 of J.H. Sobel’s Logic and Theism.

  • In another debate with Bill Craig, atheist Christopher Hitchens gave this objection: "Who designed the Designer? Don’t you run the risk… of asking 'Well, where does that come from? And where does that come from?' and running into an infinite regress?" But this is an elementary misunderstanding in philosophy of science. Why? Because every successful scientific explanation faces the exact same problem. It’s called the “why regress” because no matter what explanation is given of something, you can always still ask “Why?” Craig pointed this out and handily won that part of the debate. Had Hitchens had a passing understanding of science or explanation, he could have avoided looking foolish, and also spent more time on substantive objections to theism. (One can give a "Who made God?" objection to theism that has some meat, but that's not the one Hitchens gave. Hitchens' objection concerned an infinite regress of explanations, which is just as much a feature of science as it is of theism.)

The lesson I take from these and a hundred other examples is to employ the rationality virtue of scholarship. Stand on the shoulders of giants. We don't each need to cut our own path into a subject right from the point of near-total ignorance. That's silly. Just catch the bus on the road of knowledge paved by hundreds of diligent workers before you, and get off somewhere near where the road finally fades into fresh jungle. Study enough to have a view of the current state of the debate so you don't waste your time on paths that have already dead-ended, or on arguments that have already been refuted. Catch up before you speak up.

This is why, in more than 1000 posts on my own blog, I've said almost nothing that is original. Most of my posts instead summarize what other experts have said, in an effort to bring myself and my readers up to the level of the current debate on a subject before we try to make new contributions to it.

The Less Wrong community is a particularly smart and well-read bunch, but of course it doesn't always embrace the virtue of scholarship.

Consider the field of formal epistemology, an entire branch of philosophy devoted to (1) mathematically formalizing concepts related to induction, belief, choice, and action, and (2) arguing about the foundations of probability, statistics, game theory, decision theory, and algorithmic learning theory. These are central discussion topics at Less Wrong, and yet my own experience suggests that most Less Wrong readers have never heard of the entire field, let alone read any works by formal epistemologists, such as In Defense of Objective Bayesianism by Jon Williamson or Bayesian Epistemology by Luc Bovens and Stephan Hartmann.

continue reading »

Compartmentalization in epistemic and instrumental rationality

77 AnnaSalamon 17 September 2010 07:02AM

Related to: Humans are not automatically strategic, The mystery of the haunted rationalist, Striving to accept, Taking ideas seriously

I argue that many techniques for epistemic rationality, as taught on LW, amount to techniques for reducing compartmentalization.  I argue further that when these same techniques are extended to a larger portion of the mind, they boost instrumental, as well as epistemic, rationality.

Imagine trying to design an intelligent mind.

One problem you’d face is designing its goal.  

Every time you designed a goal-indicator, the mind would increase action patterns that hit that indicator[1].  Amongst these reinforced actions would be “wireheading patterns” that fooled the indicator but did not hit your intended goal.  For example, if your creature gains reward from internal indicators of status, it will increase those indicators -- including by such methods as surrounding itself with people who agree with it, or convincing itself that it understood important matters others had missed.  It would be hard-wired to act as though “believing makes it so”. 

A second problem you’d face is propagating evidence.  Whenever your creature encounters some new evidence E, you’ll want it to update its model of  “events like E”.  But how do you tell which events are “like E”? The soup of hypotheses, intuition-fragments, and other pieces of world-model is too large, and its processing too limited, to update each belief after each piece of evidence.  Even absent wireheading-driven tendencies to keep rewarding beliefs isolated from threatening evidence, you’ll probably have trouble with accidental compartmentalization (where the creature doesn’t update relevant beliefs simply because your heuristics for what to update were imperfect).

Evolution, AFAICT, faced just these problems.  The result is a familiar set of rationality gaps:

continue reading »

The Psychological Diversity of Mankind

79 Kaj_Sotala 09 May 2010 05:53AM

The dominant belief on this site seems to be in the "psychological unity of mankind". In other words, all of humanity shares the same underlying psychological machinery. Furthermore, that machinery has not had the time to significantly change in the 50,000 or so years that have passed after we started moving out of our ancestral environment.

In The 10,000 Year Explosion, Gregory Cochran and Henry Harpending dispute part of this claim. While they freely admit that we have probably not had enough time to develop new complex adaptations, they emphasize the speed at which minor adaptations can spread throughout populations and have powerful effects. Their basic thesis is that the notion of a psychological unity is most likely false. Different human populations are likely for biological reasons to have slightly different minds, shaped by selection pressures in the specific regions the populations happened to live in. They build support for their claim by:

  • Discussing known cases where selection has led to rapid physiological and psychological changes among animals
  • Discussing known cases where selection has led to physiological changes among humans in the last few thousand years, as well as presenting some less certain hypotheses of this.
  • Postulating selection pressures that would have led to some cognitive abilities to be favored among humans.

In what follows, I will present their case by briefly summarizing the contents of the book. Do note that I've picked the points that I found the most interesting, leaving a lot out.

continue reading »

View more: Next