## How to be a Bayesian

Just finished this book on the history of Bayes theorem and I highly recommend it.

In case youâ€™re wondering what is it, keep reading.

1/ Statistics is all about calculating probabilities, and there are two camps who interpret probability differently.

Frequentists = frequency of events over multiple trials

Bayesians = subjective belief of the outcome of events

2/ This philosophical divide informs what these two camps usually bother with.

Frequentists = probability of data, given a model (of how data could have been generated)

Bayesians = probability of model, given the data

3/ Most often we care about the latter question.

E.g we want to know given that the mammography test is positive, what is the probability of having breast cancer.

And not given breast cancer, the probability of test being positive.

4/ These two questions sound similar but have different answers.  ...

## My intellectual progress in the last decade (2010s)

A decade is a long time, about 1/8th of an average life span if you happen to live a long life. I came across Scott Alexander’s post where he wrote about his intellectual progress in 2010s and thought it’ll be a good idea to do the same for myself. When I had turned 30 two years back, I had looked back at the goals that the 20 year old me had. If you read that post, you’ll see that overall I feel that my 20s (and correspondingly, most of the 2010s) were very fulfilling. I started a company, fell in love and made myself financially independent. ...

## What does the soul of the Marionette say?

I recently finished reading the excellent book The Soul of The Marionette by John Gray. I would put this book in the same genre as one of my other favorite books, Finite and Infinite Games. Both books are short metaphorical essays on progress in (human) life.

Here are my notes from the book.

1/ First of all, what is a marionette? It’s a puppet controlled by a human via strings from above. The reason it’s graceful in its movements is because it lacks self-awareness that it’s being controlled by someone else. ...

## Life is fractal, but markets are square

I recently read Venkat’s synopsis of the book Seeing like a state, which I followed up by an excellent blog post titled The Meridian of Her Greatness. Venkat challenged people to summarize the most important ideas from that post in a tweetstorm. He said if it gets more than 100 likes, on Twitter he’ll give away \$1. I thought it was a fair deal, so here’s my attempt to distill some of the ideas into a visual essay.

1/ When humans wield their power in the world, they are limited by the linear nature of their thinking. The best example of this linearization is the top-down planning of modern suburbs. Contrast this with how nations and states emerged in a bottom-up fashion. ...

## What Gita teaches us and what it doesn’t

1/ I recently finished Menon’s translation of Bhagavad Gita, the holy book of Hindus. There’s a lot to like about it, but it leaves a few issues unresolved.

Here are my notes.

2/ The story revolves around the warrior Arjuna who faces conflict during a war with his cousins. He simply cannot bring himself to kill the people he grew up with. So he tells his charioteer, Krishna, that he’d rather die than go to war.

3/ This conflict is used as a backdrop by Krishna, who actually is an incarnation of God, to reveal the truth of the world to Arjuna. The ideas and concepts in Gita are consistent with other Hindu philosophies and ideas.

4/ The key philosophical teaching in Gita is that the human soul is one with Brahmana, the ultimate God. However, that soul is embodied and unaware that it is one with God.

5/ So, the body must go through Samsara, the cycle of birth and rebirth until it realizes its oneness. Gita stresses that the real condition is of non-separateness. That only Brahmana exists that’s beyond time, space and quality.

6/ It’s only because of Maya, the illusion, that it seems reality consists of separate beings (souls). This idea was expressed in Ramayana as well when Hanuman meets Ram.

7/ Krishna tells Arjun that each soul has a karmic accounting going on. If after death, there’s positive karma, souls are sent to heaven where they enjoy until they end up using all their balance and then they’re sent back to the Earth.

8/ If the karmic balance is negative, souls get reborn as ‘lower’ creatures.

9/ The only way to get free of this constant cycle of birth and rebirth is by

seeking a zero balance of karma while being alive ...

## Notes from ‘Nonzero: the logic of human destiny’

I make notes of books that really impact my thinking. Earlier, I made notes from The Elephant in the Brain and Skin in the Game. This time I make notes from a book that traces the arc of human history. My notes are not verbatim (unless quoted). It’s mostly what I found illuminating.

1/ Here are my notes from ‘s book – Nonzero: the logic of human destiny. I enjoyed the book very much.

The basic premise of the book is that history has a direction which favors co-operation and non-zero sum games, and that causes an increase in complexity.

2/ Starting from the first replicating molecule which co-operated with an outer layer to form first proto-cell, evolutionary and cultural history is full of examples where two entities come together to survive and progress a lot more than they would have done individually.

3/ This co-operative entity fares much better than two individual entities because of specialization. If two entities are in the same boat – that they win together or lose together – then trust is implicit.

4/ In a non-zero sum game, trust causes entities to focus on what they do best. For example, eukaryotic cells – the ones animals and plants have – emerged when two proto-cells merged, and one took the role of energy generator (mitochondria), the other specialized in protection.

5/ Some scientists believe that even nucleus in a cell is a result of an early cell merging with another cell. So M&A is not a recent phenomenon, entities have been merging because of common interests ever since life started. ...

## Notes on entropy

In my experience, entropy as an idea is generally misunderstood. Like many, I had a gut level understanding of “entropy is disorder”. It’s easy to misapply that intuition and draw wrong conclusions about areas far removed from physics (business, economies, cultures, etc.) Remember: thinking in analogies is dangerous?

So, I decided to dive deeper into entropy and here are my notes on the topic (as a series of easily digestible tweets).

1/ A short thread on ENTROPY, and its misapplications

2/ First and foremost, know that there are two different things that are called entropy: one is thermodynamic entropy and the other one is information entropy. Whenever someone is talking about entropy, ask which one.

3/ Thermodynamic entropy: it started with Carnot and Clausius, who defined it as the amount of energy/work absorbed by a system per unit of temperature

4/ Actually, more precisely thermodynamic entropy was defined at a constant temperature and in a reversible process. Roughly it translated to how much energy can go in the system without raising its temperature ...

## Notes from The Elephant in the Brain

1/ Reading @robinhanson and @kevinsimler new book â€˜Elephant in the brainâ€™. Here are my notes on big ideas from the book.

2/ Human intelligence evolved as a result of arms race of getting ahead in social situations where two contrasting incentives always existed: to co-operate or to compete.

3/ Unlike chimps where hierarchy is strictly from alpha male to least powerful individuals, language allowed humans to form coalitions and keep most aggressive individuals in check. These coalitions are where laws and norms come from

4/ Since norms cannot be exactly specified, human brains evolved to find subtle ways to work around them (lying) and to detect others working their ways around them (detecting lying)

5/ Since humans have to co-operate but others suspect that our intentions are not true, we evolved honest signals such as body language, shame, guilt, etc.

6/ Since other humans can detect our dishonest intentions, lying to others is difficult but we still have to find ways to take opportunities to exploit social situations to get ahead – to get sex, status, power.

7/ Our brains evolved to lie to themselves in order to give honest signals in social situations. That is why in order to blend in a social society, itâ€™s not just enough to lie that you believe in god, you have to actually believe that (taking help from all sorts of cognitive biases)

8/ Since we act and verbalize conscious thoughts in social situations, our brains give censored version of reality to consciousness that mostly contains info that makes us feel good about ourselves (such that others mistake us for actually being that good)

9/ This last idea is radical.

This means all our conscious thoughts (and ideas about ourselves) are hopelessly twisted ...

## Notes from Inverted Passion Unconference in Bangalore [March ’18]

After doing the first unconference in Pune, I and Roby did the second one in Bangalore on March 11th 2018. These are my notes from the event.

### Fireside chat with Kunal Shah, Founder of Freecharge (sold for \$400mn to SnapDeal)

Here’s the entire audio transcript on Soundcloud. My key insights and learnings from the conversation (we were taking whisky shots while chatting, so when you hear me say ‘shots’ you do the math). Also, eChai has collated many people’s tweets into one page (so

you can read everyone else’s insights from our chat ...

## Notes from ‘Skin in the game’ by Nassim Nicholas Taleb

Nassim Nicholas Taleb, the famous author of Fooled by Randomness and The Black Swan, has come up with a new book titled Skin in the Game. I finished it over the weekend and here are my notes.

### Insights (and points I agree with him on)

Human systems are systems within systems, interacting in complex ways. No article / paper / logical argument can capture all interactions of such systems and their evolution over a non-trivial amount of time. So one shot, large scale interventions (such as invasion, UBI, CRISPR) are extremely dangerous because we now have people in power who can order large scale tech-driven interventions across a large section of society.

– People with fuck you money should call out famous or powerful people when they are wrong

A scientific result takes a slice of the world thatâ€™s impossible in reality. Our real world is dynamic, full of interactions and any static slice necessarily misses that

Time is the ultimate test of robustness.

Itâ€™s safer to describe the past than to predict the future, but if you must predict it, you must share its downside

– When a thing is described, the limitations imposed by the need to hold that concept in mind and communicate it to others isnâ€™t generally recognised as limitations. In reality, the thing (say voters in Bihar) has a history, embedded in other things, interacts with other things and has goals that evolve that itself isnâ€™t aware of. Try communicating all that to others.

– Our perception of roles that people are playing in a system are usually static and short sighted.

We forget. But history doesnâ€™t care. ...