Review: Land of the Seven Rivers

I read Sanjeev Sanyal's "Land of the Seven Rivers: A Brief History of India's Geography" with much interest after I heard a podcast of his talk at LSE.

It presents Indian history (and prehistory) through the lens of geography and climate. The new perspective allows for some fascinating reinterpretations.

For example, Sanyal claims that the Ramayana was a oriented along a North-South axis (Ayodhya to Sri Lanka), and that the Mahabharata, was more aligned along an approximately East-West axis. Remnants of these paths still exist in the form of segments of national highways.

Similarly, he tells the fascinating story of why Gautam Buddha went to Sarnath to propagate his new philosophy (it sits at the intersection of two important commercial routes, which allows for rapid dissemination of goods and ideas). He dwells on the role of "pillars", and how some of them became a canvas on which successive waves of emperors would carve out their names for posterity.

One surprising aspect (which perhaps should not have been that surprsing) is how much the climate has changed even in the last few thousand years, and how a response to such massive climate change has shaped the course of history (example, the end of the Indus-Saraswati valley civilization). As we deal with a climate crisis of our own, it is useful to look at the massive disruption such upheavals cause.

If another reason to study history is to learn how we got where we are, then I think this book shows us how big of a role Nature and fortune (as opposed to politics and monarchs, which are the usual lens through which history is told) played in shaping the course of events.

The book is full of factoids and clever observation of patterns. Throughout the book there is an underlying concept of "continuity" and the idea of "nationhood" extending from 90 million years ago, through the merger of the Indian subcontinent with Asia, the early river valley civilizations, through the last couple of millennium, up to the present day with a discussion of the Indian diaspora.

It is truly a fascinating read, and very highly recommended. 

Review: The Black Swan - the impact of the highly improbable

Having read some great reviews that this book has attracted,  it was with much delight and anticipation that I finally borrowed this this best-seller by Nicholas Nassim Taleb.

Instead of saving the summary for the end, I am going to spit it out right at the beginning.

I am glad I picked this book up from the library.

It is the kind of book that you could read once. In fact, a good summary could probably distill the essence of the book into two pages, without sacrificing much.

Once upon a time people thought all swans were white. Everything was hunky dory, until black swans were discovered in Australia. The book derives its title from this "highly improbable event". I don't know how many tectonic plates shifted after this discovery, but Taleb does make an important point.

Unfortunately, the point has been made before, and it has been made before even more eloquently. For example Einstein is alleged to have said, "No amount of experimentation can ever prove me right; a single experiment can prove me wrong."

That is really my primary grouse with the book. Most of it has been said before more eloquently.

But the book is not without its merits.

Taleb lays down the three characteristics of a Black Swan: rarity, extreme impact, and retrospective predictability.

Events like 9/11, the rise of the internet, the market crash of 1987, Harry Potter - they are all Black Swans.

By rarity he means power-law rarity, not a six-sigma type of rare event. From the linked wikipedia article

The distribution of a wide variety of natural and man-made phenomena follow a power law, including frequencies of words in most languages, frequencies of family names, sizes of craters on the moon and of solar flares, the sizes of power outages, earthquakes, and wars, the popularity of books and music, and many other quantities.

Power law distributions are scale invariant - they don't have a mean or variance, like most commonly studied distributions do. They aren't widely used in economics, and perhaps they should be, but again Taleb is not the first person to make this point. Mandelbrot did it much earlier and much better.

Extreme impact is easy to understand. Unlike height, variables that obey power law distributions can wreak havoc. If Bill Gates joins a group the average height (a normally distributed variable) does not change appreciably, but the average income goes berserk. Taleb calls the former Mediocristan, and the latter Extremistan which may be useful labels for some people. To me they were more unnecessary pompous verbiage (like Ludic fallacy, scalable, nonlinearity), that the author loves to throw around at the slightest provocation.

Narrative fallacy or retrospective predictability is the tendency of experts and media to explain unpredicted events after the fact, as if they were inevitable. I have to confess that this was the only chapter in the book that I found interesting, because I had not heard it discussed so fully before.

Where the book gets boring is when the author goes off on tangents.

Usually I like tangents. I love footnotes. But when tangents take place with reckless abandon, it results in a chaotic laser show.

But that is not all. The book gets viscerally painful, when he author stoops to cheap shots. To be fair, he may have been hurt by those who he seeks to hurt, but true generosity is the mark of a great man. For example on page 90, he rants:

Where it gets painful is when you see one of your peers, whom you despise, heading to Stockholm for his Nobel reception.

If this was an isolated sentence, it could be easily forgiven. After all, we are all works in progress. But the book is soaked in that kind of "small-think". Another annoying habit is the  castigation of the bell curve ("that great intellectual fraud"), ad nauseam. The bell curve is often inappropriately applied - we get it! But hearing Taleb go on and on, I almost felt like taking that bell curve and banging it on his head so that he would stop.

It is surprising that I found the book utterly disappointing. I actually share quite a bit of Taleb's worldview. I agree that most economists have bogus predictive abilities, that not listening to popular media is a recipe for knowledge, and that it is better to be approximately correct than precisely wrong.

As I said: I am glad I picked this book up from the library.