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Ask HN: Which books teach mental models?

Read the piece by Mutaschak[1] yesterday and found myself agreeing with components of the piece but distinctly feeling that some well-crafted books take a more active role in conveying and teaching mental models than simply summarized facts (which can be done well, but is subject to being forgotten).

The question, then, is what books effectively introduced a new mental model or perspective?

Two recent examples from my own reading, non-fiction and fiction:

Loonshots (Bahcall) - model & "rules" for structure of innovation in orgs is introduced, discussed from various perspectives, examples given, summarized in text, repeated.

Overstory (Powers) - character stories all reinforce the perspective of an alternative relationship with trees and plants, the giant ecosystem and systems thinking.

[1] https://andymatuschak.org/books/

473 pointswintercarver posted 3 months ago97 Comments
schuetze said 3 months ago:

Thinking in Systems: A Primer by Donella Meadows

Once you start looking for positive and negative feedback loops in the world around you, it's hard to stop. In particular, Meadow's book is great because it also goes beyond +/- loops in isolation, and shows more complicated patterns, such as eroding goal patterns and traps that often cause public policy interventions to fail.

Ghost_of_USSR said 3 months ago:

+1 from me. Can't stop either :) But I came to the same idea while reading "Feedback systems: an introduction for scientists and engineers" by Karl Johan Åström and Richard M. Murray.

cosmie said 3 months ago:

+1 on Donella Meadows. I've recommended her work here a few times. I've always had an affinity for perceiving systems, but was pretty bad at expressing my thoughts. Donella's work was fantastic for providing definition to my thought patterns and improving the way I articulate and express myself.

freddieoduks said 3 months ago:

+1 I just recently read this book and i was met with gem after gem. Also made me start looking at the world in terms of feedback loops, is it a balancing, goal-seeking or reinforcing feedback loop? How tight are these feedback loops? etc. Definitely a must read!

zsam said 3 months ago:

which book?

zsam said 3 months ago:

I didn't get the name of the book

Rainymood said 3 months ago:

Thinking in Systems: A Primer by Donella Meadows

zsam said 3 months ago:


quickthrower2 said 3 months ago:

On Amazon:

> Donella Meadows remained a pioneer of environmental and social analysis until her untimely death in 2001.

That’s sad

tlb said 3 months ago:

There are many good recommendations here, but I’d add that reading books about mental models is worth 10%, while practice thinking about real situations is 90%.

To get practice, you can’t just sit and scratch your chin. You have to make a predction, write it down, then see how real life played out a few years down the road. It helps to write down predictions you considered but rejected and why.

plinkplonk said 3 months ago:

+ 100.

the idea that sustained practice till you become fluent in the use of specific mental models is missing in much of the literature.

Just like learning any other skillset, using mental models effectively takes a lot of work.

This is often the missing key to effective use. It is one thing to read about a mental model (say Donella Meadows's systems thinking), and be able to recall the material from memory and quote it and so on. It is quite another to be able to apply that model (here systems thinking) to real life situations and get useful results.

I know many people who can quote chapter and verse of literature about mental models, but their thinking remains confused and ad hoc when it comes to dealing with real life problems.

To practice, one can also apply mental models to case studies/situations from the past and compare to the outcome predicted by the model and the actual outcome.(To be fair, there is a risk of making mental models fit the known outcome here, so one has to be aware of that)

EDIT: (not the same as mental models, but since someone mentioned ARIZ/TRIZ above) Edward De Bono's "Serious Creativity" and "Lateral Thinking for Management" (yes terrible title) are full of thinking tools that can be practiced systematically. Most of his books are repetitive and have varying ratios of fluff to core material, but these two together have most of his useful ideas.

douglaswlance said 3 months ago:

That sounds like quite possibly the least effective method of learning.

There are people out there who have done all that work for you. All you have to do is pick up a book, learn their models, then stand on their shoulders as you develop your own.

zeroxfe said 3 months ago:

> That sounds like quite possibly the least effective method of learning.

It maybe less efficient, but in my experience, practice has consistently been the most effective way to learn something.

If you're looking for efficient, then you'd want a well-structured mix of theory and practice.

> All you have to do is pick up a book, learn their models, then stand on their shoulders as you develop your own.

Rarely does this work for any complex topic. I can't imagine learning math, or languages, or coding by simply picking up books. IMO, these models are very similar -- they have a ton of depth that can't be internalized without practice.

ntoshev said 3 months ago:

Definitely one of the most efficient ways. All the literature about expert performance stress on deliberate practice.

douglaswlance said 3 months ago:

He edited his comment.

brianbreslin said 3 months ago:

If you haven't seen it, this is one of the best resources on the subject: https://fs.blog/mental-models/ Farnham Street blog has a TON of fascinating articles.

DEADBEEFC0FFEE said 3 months ago:

There real challenge is remembering them, and determining which to use and investing the time to use them.

brianbreslin said 3 months ago:

right, but i would say do a superficial pass through of all of them and then study more the ones that FEEL logical. The ones that work best with your existing logic will likely serve you most.

miguelrochefort said 3 months ago:

Spaced repetition could help to memorize them.

rdyson said 3 months ago:

+1 for Farnam Street. They just published a book based on their blog posts about mental models. You can find the book here: https://fs.blog/tgmm

prennert said 3 months ago:

I am reading The Fifth Discipline by Peter M. Senge at the moment.

It is a fantastic book that came out in the 90s and was updated in the 00s. It describes the need and practical solutions to systemic thinking for a learning / adaptive organization. It covers a lot of different areas:

- introduction to systemic thinking (via a very good example and then a formalised introduction to three often occuring systems)

- personal mastery (life long learning with a reflective attitude) as foundation for a learning organization (i.e. how can personal self improvement be scaled up to a similar process with many people involved while keeping everything together)

- practical examples at the end (I have not read that part yet, I am just inferring from the chapter titles)

Even that I have not read the book completely, it is now one of the books I always recommend when friends with interest in founding a startup ask me for advice. It is one of the very few "management" (loose category) books I have read that I actually found useful and actionable. Only problem is that it is quite big so it takes dedication to read through it.

Edited for formatting, title..

plainOldText said 3 months ago:

Small correction: The title is The Fifth Discipline.

prennert said 3 months ago:

Not sure how I could get that wrong. I guess. I need to look at the title page more often.. Thanks. Corrected it.

jimmcslim said 3 months ago:

'An Introduction to General Systems Thinking' [1] by the late, great Gerald Weinberg?

[1] https://leanpub.com/generalsystemsthinking

Edit: no relation (I believe?) to Gabriel Weinberg of Duck Duck Go who is also being mentioned in this discussion.

ncphillips said 3 months ago:

I enjoyed this book a lot but Thinking in Systems by Donella Meadows is definitely a better introduction to systems thinking

pjmorris said 3 months ago:

+1 for this. Arguably all of Weinberg's works teach mental models. 'Are Your Lights On?' is an easy introduction to his writing and thinking, and 'Exploring Requirements: Quality Before Design' is directly applicable to any software project involving collection of requirements (I thin that's all of them.)

neves said 3 months ago:

Weinberg books are full of wisdom. Systems Thinking is at the core of his ideas. You can find almost all of his books in LeanPub at a very accessible price: https://leanpub.com/u/jerryweinberg

If you are outside the USA, probably the kindle edition will be cheaper.

rramadass said 3 months ago:

1) Sources of Power: How people make decisions by Gary Klein

Introduces https://en.wikipedia.org/wiki/Recognition_primed_decision It really resonated with me.

2) Thinking and Deciding by Jonathan Baron. Quite thorough and comprehensive.

3) There are also books on "TRIZ"(https://en.wikipedia.org/wiki/TRIZ) a technique for problem solving, which arose from the former Soviet Union.

edem said 3 months ago:

Not a book, but a course. This one was insanely useful for me and I've applied the models countless times: [Model Thinking][0]. I heartily recommend this to anyone who wants to learn about models and has some spare time:


sonabinu said 3 months ago:

Scott Page ( from U Michigan who is the creator of the class) has written a book on models called Model Thinker. I’m currently reading it and think it is pretty good!

edem said 3 months ago:

Scott Page is an awesome guy!

wintercarver said 3 months ago:

NOTE: Sorry it wasn't quite clear from my question, but I was hoping to explore books that were more focused on a single model, not books that teach or enumerate many models.

My thinking was that the reference-style books are easy to forget and enjoyable but subject to being forgotten specifically because you spend less time with any single model. Some books are closer to survey courses, reviewing a lot of material. They aren't bad, they can be fun. But the books I cited above specifically feel focused on single concepts, and thus "teach" them quite well imo.

So, I am specifically curious about books that go deep, evaluate, or really drive home individual models.

btilly said 3 months ago:

https://superthinking.com/ introduces a whole bunch.

It grew out of https://medium.com/@yegg/mental-models-i-find-repeatedly-use....

I would suggest starting there.

wintercarver said 3 months ago:

I guess my interest is actually in finding books that teach _one_ mental model, or at most one with a few variations to really send the point home. There's no shortage of fascinating compilations or general studies (e.g. Thinking Fast & Slow is not a walk-away-with-one-concept book, apart from perhaps "oh damn there's a lot of biases out there!"), but there might be a shortage of books that effectively focus on a single concept.

gala8y said 3 months ago:

I wouldn't call it a mental model, but Voice Dialogue method has tremendous positive impact on people's well-being and consciousness. Somehow it fits your question, I think. It is a mental model of sorts. "Embracing Our Selves", a book by Sidra and Hal Stone, is a beautifully written introduction.

mrmrcoleman said 3 months ago:

I strongly recommend checking out the Cynefin framework: https://en.wikipedia.org/wiki/Cynefin_framework

Knowing which context you're in provides a useful tool when choosing mental models to approach the problem.

Having said that, 99% of mental models is practice as adopting a mental model is often an emotional problem too.

For example, while Cynefin may suggest an iterative approach for complex domains, you'll still need to be emotionally able to deal with the natural outcomes of iterative problem solving

e.g. being comfortable making decisions with incomplete data, handling failure, communicating progress when there is no clear way to estimate scope.

Zanni said 3 months ago:

Language in Thought and Action by S. I. Hayakawa is an introduction to General Semantics and deals with the limitations of language-oriented mental models, e.g. "the map is not the territory," a reminder that a model is just a model and not reality (or what Joel Spolsky would call "a leaky abstraction"). [0]

The World of Null-A by A. E. Van Vogt is a science-fiction novel with a world that has largely adopted General Semantics. [1]



traderjane said 3 months ago:

I think the truth is somewhere in the middle. The model is a map to the world, but at some point, you start thinking about the implications of your model and you work out an unusual idea, and then it turns out the model implicates new phenomena.

What guided your ability to find the hidden gold nugget? Lucky guess? Or at some point, if you get the construction of a map so right, the map will help you compute interesting truths yet discovered.

andrenth said 3 months ago:

* Poor Charlie's Almanack: The Wit and Wisdom of Charles T. Munger

* Seeking Wisdom: From Darwin to Munger

* The Model Thinker: What You Need to Know to Make Data Work for You

* The Great Mental Models

james_s_tayler said 3 months ago:

I'm reading The Model Thinker at the moment. +1

andrenth said 3 months ago:

There is also a course on Coursera taught by the author which goes well with the book.

ineedasername said 3 months ago:

Perhaps a different flavor of mental model, but a great book: "Metaphors We Live By" by George Lakoff

mikhailfranco said 3 months ago:

It seems like MWLB should be able to provide the basis space for all other models, and looser networks like ConceptNet.

I imagine each concept a bit like a Chinese character, with radicals (basis set), composition using scaling and placement (metric space relations), along various abstract dimensions (meaning and sound in the case of the characters).

It's a project that's been on my TODO list for far too long.

james_s_tayler said 3 months ago:

I recently read Shortcut, which is another book about analogy/metaphor and the role it plays in thinking. Highly recommend anyone to read one or two books on this topic.

bartimus said 3 months ago:

This question is strange to me.

Mental models are simply how your brain works. You don't need to read books about them before they become effective.

You don't need to understand how your legs operate before you can learn to walk.

The only thing you can learn are concepts. But there's billions of them. It's what education does.

It's somewhat useful to understand how the brain operates through mental models. But there's only a single mechanism at play. Basically it's what happens when your brain sends emotional signals about your environment in relation to your mental model of it.

vmurthy said 3 months ago:

True there are billions of concepts but if you think about it, a few concepts explain a ton of things. For e.g., incentives. A simple concept in theory but apply the right incentives if you are leading teams and you'll see a whole lot of improvements. And that's the beauty of mental models. You don't want billions of them. Maybe 20-30 of them have enough applicability for most of the things that you might want to change in your immediate milieu.

Here's an example :

"The heart and soul of the integrity of the ( Fedex )system is that all the packages have to be shifted rapidly in one central location each night. And the system has no integrity if the whole shift can’t be done fast. And Federal Express had one hell of a time getting the thing to work. And they tried moral suasion, they tried everything in the world, and finally somebody got the happy thought that they were paying the night shift by the hour, and that maybe if they paid them by the shift, the system would work better. And lo and behold, that solution worked."

Source : https://fs.blog/2017/10/bias-incentives-reinforcement/

Edit : clarity and some speeling mistakes ;-)

bartimus said 3 months ago:

Yes, I agree logical concepts can be abstracted into generic core concepts. Like how the concept of "picking up a coffee cup" can be abstracted into the more generic core concept of "picking up an object" which can be applied more broadly.

But that's more about logical reasoning than it is about mental models. A mental model is how the brain understands a logical concept.

There's also a danger with it becoming counter-productive. For example you might want to learn how to ride a bike. You educate yourself about the technical workings of the bike. How your body will balance itself. When you need to apply force on the paddles. Which muscles you will use to apply that force. You gain full understanding of the concept of "riding bike". This doesn't mean, however, you now have a proper functioning mental model of it. The other kid didn't do all the research you did. He just got on his bike and started trying. After some trial and error he's already making some distance. His mental model of "riding bike" might already exceed yours even though you have a better understanding of how it works. You might even be learning more slowly since you're constantly distracted by how the development of your mental model matches up with your understanding of it.

I believe this is also why some people stutter. They're constantly thinking about their speech. Their mental model of "speaking" gets interrupted by them thinking about it.

So I agree it's valuable to understand core concepts. It's valuable to think about how the brain works. It's valuable to be able to use your feelings (caused by your mental model) as tools to effectively make use of your brain. But I'm not sure it's wise to mess with the mental model that the brain creates about concepts. Or to define a logical concept as a mental model.

xtiansimon said 3 months ago:

The philosopher Peter Sloterdijk describes ‘ideology’ as a personal idea of how the world _really_ works. You could call that a mental model. However, when I think specifically about the subject ‘mental models’ I return to the concept I learned about first in the Coursera course Model Thinking by Scott E. Page (University of Michigan). He teaches a survey of many different models. For example, there is the Threshold Model [1] developed by Mark Granovetter and others. This general concept can be applied to a variety of problems from predicting the spread of infectious disease, to the spread of social trends in human culture. While the concept can be generalized, it’s also theoretically grounded in mathematics and statistics.

For this reason I find the OP’s follow-up somewhat—misguided? Seems like he needs to pick a topic and do some research. Unless we’re just talking about our favorite books, which is basically what the thread has become. And I love it.

[1]: https://en.wikipedia.org/wiki/Threshold_model

wintercarver said 3 months ago:

Just reading through comments to aggregate notes, and as the OP, yep: I meant something closer to "favorite books" but with the condition that they happen to introduce, by intention or unintentionally, a (single) "mental model" (not to be too strict about the definition) or perspective of sorts. I realize now my original question was not that clear, sorry about that!

xtiansimon said 3 months ago:

Well. Thanks for the apology; I feel the pain. Broad minded thinking runs into this problem frequently. But the more I think about it—What’s good in literature and science and also satisfies the constraint of a grand conceit—the more I believe the only satisfactory ‘answer’ is the one they answer for their self. I’ve been trying to answer some similar questions in philosophy of language since 2005, and I’m still at it. I say, go for it. We will all be interested to read what you write.

wintercarver said 3 months ago:

Thanks for the encouragement to write, it was entirely unexpected and pleasant - kind of a glimmer of the olde, small internet days. I didn't have this piece in mind when posting on HN, but all the book recommendations got me thinking and this is what managed to land on the word processor.


P.S. I am not part of “Journal,” and don’t use it. One of their people reached out to me and asked if I’d submit my piece to their publication.

cannonedhamster said 3 months ago:

I wish they had gone into what they meant by paid by the shift. Does that mean they got to go home early if the work was done? They had to stay later if it wasn't? I'm not sure that paying for 8 hours is much incentive, and forcing people to work more for the same money seems like it would be a recipe for disaster. Giving a reward for getting through the mail faster by getting to go home early send like a pretty awesome reward though.

haraball said 3 months ago:

I worked in a warehouse once, emptying containers full of boxes. We were paid by "container hours", so if we emptied a 4 hour container in 2 hours, we got double salary. That was a good motivation to work fast.

CJefferson said 3 months ago:

Actually, I think your point is really strong, but probably in the opposite direction to how you expected.

Learning about the number of calories in everything, and reading research that said the whole "low fat" movement wasn't useful, was what finally helped me lose weight.

Reading about the best ways to exercise helped me train effectively.

So maybe I do need to read more books about the brain.

kkarakk said 3 months ago:

And yet training/training manuals exist for running for those who need it(for ultramarathons/sprints etc)

imakwana said 3 months ago:

# Intuition Pump and other tools for thinking by Daniel Dennett

# Books edited by John Brockman - 1) This Explains Everything, 2) This Idea is Brilliant, 3) This Will Make You Smarter, 4) Thinking

# Personal MBA by Josh Kaufman

Also second the recommendation of other books based on Charlie Munger's wisdom and farnam street's reading list.

enkiv2 said 3 months ago:

I second the recommendation of Intuition Pumps.

To that, I would add Metamagical Themas by Douglas Hofstader & Prometheus Rising by Robert Anton Wilson. (Wilson gets a little hippieish, but he does a better job of knocking down unjustified tunnel-vision than Hofstader or Dennett do.)

kesor said 3 months ago:

"The Goal" by Eliyahu Goldratt, and other of his books are great books to learn how to think.

It is a more concrete example of Systems Thinking that is applied to various environments, manufacturing in "The Goal", marketing and strategy in "It's Not Luck", projects in "Critical Chain", retail in "Isn't it Obvious", and personal improvement in "The Choice".

bitforger said 3 months ago:

I wrote a blog post today about how I don't believe in the abstract plane, if you're into it: http://mitchgordon.me/philosophy/2019/05/12/non-existence-of...

alexpetralia said 3 months ago:

I'm surprised there's no mention of consciousness or Cartesian dualism here. That is generally where "abstraction" comes in - as a tool for humans. I don't think anyone is claiming it to be a physical property of the universe.

stakhanov said 3 months ago:

Gabriel Weinberg, Founder-CEO of DuckDuckGo recently wrote one that is about to hit the shelves: "Super Thinking: The Big Book of Mental Models"

mxschumacher said 3 months ago:

he published a long list of mental models in 2016: https://medium.com/@yegg/mental-models-i-find-repeatedly-use...

emre said 3 months ago:

I would recommend Poor Charlie's Almanack by Charlie Munger and these following two books:

The Model Thinker: What You Need to Know to Make Data Work for You by Scott Page

https://www.amazon.com/Model-Thinker-What-Need-Know/dp/04650... and

The Great Mental Models: General Thinking Concepts by Shane Parrish


apo said 3 months ago:

Design Patterns by Gamma et al. would be an example from software architecture. It catalogs a couple of dozen patterns that recur in projects regardless of their specific domains.

Open Source Software Licensing by Rosen is another. It identifies two broad categories of open source licenses and shows how various licenses fit into each.

These two books gave me a framework for thinking about large areas that had until I read them been quite confusing. They turn a chaotic jumble of special cases into a simple framework for forming hypotheses and making predictions.

abhiyerra said 3 months ago:

Really enjoyed Science Strategy and War. Basically using the OODA loop and using mental models to make rapid decisions. The best book on John Boyd’s OODA loop in my opinion.

rom16384 said 3 months ago:

One book that is often recommended is Pólya's "How to solve it" [1], although it's more directed at solving mathematical problems than general mental models.

[1] https://en.wikipedia.org/wiki/How_to_Solve_It

sridvijay said 3 months ago:

Competing Against Luck (Christensen) - models on how to think about innovation, and the "jobs to be done" theory (what job is the customer hiring my product/service for)

Such a small shift in perspective, but it makes such a dramatic difference! Really recommend reading if you haven't already.

wintercarver said 3 months ago:

Has been on my list for a while! Thanks for the nudge. BTW, as a fan of Christensen's classic The Innovator's Dilemma, I thought Loonshots was quite good as an alternative perspective where Product-type and Strategy-type innovations are discussed in comparison to Christensen's sustaining vs disruptive innovations.

daniel_iversen said 3 months ago:

I love The Decision Book: https://www.goodreads.com/book/show/9793361-the-decision-boo...

... read and skim it quite a few times and it's super nice and quick to use.

kitd said 3 months ago:

Analysis Patterns by Martin Fowler.

Similar to GoF Design Patterns, but at a higher level of system analysis.

said 3 months ago:
richajak said 3 months ago:

My opinion would be different, I believe the good understanding of human behavior is the key, e.g. what motivates people, reward system, FOMO, etc. Try to read "Charlie Munger's 25 Cognitive Biases".

poormystic said 3 months ago:

Anything by Krishnamurti. Don’t be fooled by the name; he’s a good thinker :)

anhldbk said 3 months ago:

"Man's Search for Meaning" by Viktor E. Frankl may be?

honzzz said 3 months ago:

Yes. And if I may continue with another old book that IMHO deserves to be mentioned: Neurosis and Human Growth by Karen Horney.

adaszko said 3 months ago:

What mental models have you learned from it?

keithnoizu said 3 months ago:

Possibly more abstract than what you are looking for but Object-Oriented Design Heuristics is a decent text.


anupsurendran said 3 months ago:

I have been struggling with this. Obviously Farnam Street and some medium posts have done a great job here. I wanted to teach mental models to a younger audience and make it more fun and actionable so I just started this and am collecting a group of kids (including mine ;) ) http://www.enchanting.io

AlchemistCamp said 3 months ago:

Gabriel Weinberg of Duck Duck go recently released an entire book devoted to mental models. A few years ago, he also wrote a good article that gives an early idea what he was thinking about here:


ForHackernews said 3 months ago:

I'd recommend "The Art and Craft of Problem Solving" by Paul Zeitz, who coached the U.S. International Mathematical Olympiad team. https://www.amazon.com/exec/obidos/ASIN/0471789011/artofprob...

tim333 said 3 months ago:

There's Munger's talk. Not a book but quite good anyway http://csinvesting.org/wp-content/uploads/2014/05/Worldly-Wi...

alexpetralia said 3 months ago:

Not a book, but here is a shameless plug for my newsletter where I write regularly about mental models I find interesting: https://alexpetralia.github.io/newsletters

tmaly said 3 months ago:

I have found Poor Charlies Almanack by Charlie Muenger to have quite a few.

Thinking Fast and Slow is another great book that explains some of the mental models well.

The Art of Thinking Clearly is yet another that is actually more like a dictionary of mental models.

LeonB said 3 months ago:

“Thinking in Bets” by Annie Duke takes you through a specific model.

“Principles” by Ray Dalio gives a mesh of models that Ray has learnt or improved.

quickthrower2 said 3 months ago:

I’ve been thinking I wish someone would write a mental model oriented book converting the models for git, react/frp, OO, prototypical OO, Kubernetes, blockchain, DB indexes, peer to peer networking and whatever else.

Maybe each chapter is a different author.

I think mental model first learning would be a lot faster. Each git command can be explained in the mental model rather than as a stand-alone thing.

You could probably sum each one up in 10 pages or less. No code, no commands, just diagrams and a good explqination.

akudha said 3 months ago:

I kinda understand what you are saying, but not fully. Do you have an example of such article (or video) on one of the topics you listed?

quickthrower2 said 3 months ago:

I don't have an example sorry.

netcan said 3 months ago:

Modern (post renaissance) history, economics and political theory are often totally model focused.

Ibn Khaldun is (in my definitions) the earliest example). He describes mesapotamian history, for example, as a process where barbarians take a city, gradually become soft urbanites and then it happens again. It's a model rather than an occurrence.

It's a predecessor of Adam Smith, Marx, and even 2019 people like Yuval Noah Harari. The thesis is a model. Facts are tests and/or values for the model, not the thesis.

insomniacity said 3 months ago:

Not a book, but I recommend the Coursera Model Thinking course.

said 3 months ago:
sus_007 said 3 months ago:

Not exactly a book, but here's a podcast on the topic by Sam Harris with Shane Parrish of the Farnam Street blog.


magnamerc said 3 months ago:

I'm sure this is where this is coming from, but if not, Sam Harris's latest podcast is about mental models. I know it's not a book, but I found it insightful.

shirajec said 3 months ago:

The Chimp Paradox by Professor Steve Peters

said 3 months ago:
bigred100 said 3 months ago:

The Catechism of the Catholic Church

70122-_6 said 3 months ago:

If a bloke is chained to atree, ya don't blame the tree .... do you?