Abdul Kalam

Snark is easy.

Among the most visited posts on the blog is a flippant piece on a speech our late President APJ Abdul Kalam made. In the post, I make fun of Kalam’s flubbing some grammar; I make fun of the circular nature of his prescription for world peace. I make fun of his earnestness.

I made fun; it’s easy to make fun.

Most of the pushback has been equally childish. “Go kill yourself” is not an argument, to say nothing of being ironic coming right after ‘how could you say such mean things’?

The true test of a man is in how he treats those he has power over, goes the saying. I work for somebody who saw first-hand how Kalam treated subordinates. Kalam saw right through people, RN says. He saw who could or couldn’t do what, and didn’t put hierarchy before knowledge. He made you feel special for being part of his team. RN’s words, as best I can remember them, were “if you could do what was necessary to get the project to work, he’d treat you like the most important person”. As a recruit into DRDO and then ISRO without a PhD, it took other great men–Satish Dhawan and Vikram Sarabhai (and Raja Ramanna, I think)–to see Kalam’s potential. Kalam’s contributions to the Indian missile defence programme dwarf those of anybody else any of us can name, PhD or not.

All of which is to say I’m thinking of writing again. The first post on my return has gone well. But one does not simply walk into mordor pick up where one left off with no indication of having introspected, of having seen time pass by.

I’ve made apologies for doing dumb things before. I daresay I’ll make them again. Let’s not call this an apology; perhaps that’s too strong a word. Let me say only that the point some commenters made on the original Abdul Kalam post that snark doesn’t always show wit or cleverness is well taken, and will be remembered as I try and get better at whatever it is I’m doing here.

Astronomy, evolution, and the tea-seller

UPDATED BELOW

There’s this small roadside tea-shop next to the Centre. The man who owns and keeps the shop is from Bihar. We call him Pandey-ji. He’s a colourful man and he is, if not happier, more cheerful than I can be. He is a poet of sorts (do you ‘remember’ Johnny Walker’s sar jo tera chakraye? He writes (not that I know he can write) poetry of that oeuvre). His best one was about this country we live in–his country, our country (mera desh tarakki kar raha hai // har shehar mein chori, daka sab ho raha hai, mera desh tarakki kar raha hai), a little heavy-handed, perhaps, but the sort of anger that I might put down in writing.

Pandey also asks me, every time I go buy chai and smokes from him, something or the other about science. His most frequent questions have been about astronomy and evolution (Hey, is the Earth a sphere, did you say? And we go around the Sun and the Moon goes around us? How high is the Earth’s atmosphere? What’s there outside? Nothing? So a man wouldn’t be able to breathe? How did human life come about, anyway? We evolved from single-celled life, you say? How did that life get here? Panspermia?).

These are not dumb questions by any stretch. I say that because he always adds, after I’ve answered his questions with whatever Hindi I know (what’s Hindi for ‘Oxygen’, do you know? I blabbered for two minutes trying to explain to him what Oxygen is in trying to answer why none of the other planets of the Solar system have life), that he’s an uneducated man who can only ask these questions and try and learn something. These are questions that have bothered philosophers* for millennia; only for the last four centuries have we known that the Earth isn’t the centre of the universe, that it’s a planet in an orbit around the Sun just like half a dozen others. And only for the last century and a half have we known what is today the backbone of all biology, evolution by natural selection. So not dumb questions, then.

My answers, though… they’re a different matter. It isn’t, of course, that the answers are hard. We’ve known the answers for quite some time now, like I said. A reasonable class 12 kid should be able to answer most of these questions. It is that my facility with Hindi can only take me so far (“I can count to nine, and ask where the bathroom is”). What I would really like is to be able to show Pandey the Hindi version of Cosmos (Carl Sagan’s Cosmos, if you insist on being an originalist).

I happen to know Carl Sagan’s Cosmos is available as a book. Is there a Hindi translation/equivalent?

*ADDED IN PROOF: I say “philosophers” here and comment in the next paragraph that class 12 kids could answer most of these questions. I must add that this is not to be read as approval of Steven Pinker’s views on philosophy.

In which I send you off to read an article in The Caravan. Mine.

And Anjali Vaidya’s. It was her idea. She was very nice and included me in it.

The article’s called Shelved AwayIt’s about Select Book Shop in Bangalore. It’s only one page or so and features in The Lede. Do read. I’ll start you off with the first paragraph:

JUST OFF BRIGADE ROAD in central Bangalore is a quiet store, remarkably removed from the nearby bustle. This is Select Book Shop, a name familiar to many book lovers in the city. The store overflows with books old, new and rare, and the two men who will direct you to the treasures within are the owner KKS Murthy, and his son Sanjay.

Questions, comments, bouquets, brickbats and so forth are welcome.

Anandwan and the Maharogi Sewa Samiti of Baba Amte

Sourabh Diwan told me about the late Baba Amte‘s organisation, the Maharogi Sewa Samiti, Warora, and the work they have been doing to help rehabilitate people afflicted with leprosy. They are now calling for help towards building a corpus, to supplement the pittance that the government of Maharashtra gives them for support. There’s an appeal (pdf, English). They say they’ve helped 2.3 million people over the last 60 years. I find that number inspirational. I also think it’s heartening that they hope to do work of gigantic proportions.

Please consider donating.

Tell a story – 2 – With a graph

There are geeks and nerds and there are geeks and nerds. The thing about geeks and nerds is that most of us tend to be socially awkward. Perhaps this will help you understand better: some of us are the Leonard Hofstadter kind of socially awkward – we want to fit in, but don’t know how to. Some of us however, are the Sheldon Cooper kind of socially awkward – we border on the misanthropic.

The thing is, though, that even Sheldon Cooper has a certain bunch of people he is friendly with. Vattam was telling me last night that I tend to be this way. It seems he says, and I agree, that I have a circle of friends with whom I’m positively garrulous, but around everybody else, I go into a shell.

There can be one more dimension to this, it turns out: Sheldon Cooper, as a rule, never has more than four friends; it’s too hard to maintain more than four friendships, he says. The number of people I’m prepared to let my guard down around isn’t that restricted. I’m just nutty about who it is I let into this ‘circle’. Time spent together seems to have nothing to do with this. Neither does gender. Let’s just say there’s a reason even I call this behaviour of mine ‘nutty’.

And now, since the title of this post says ‘graphs’, here’s a graph that says everything I’ve just said:

[graph]

[/graph]

If you’re somebody this graph applies to, where in this plane do you think you are?

[End. Fini. Kaputski.]

The Probability Mess – I get email

I wrote about some probability calculations that I’d done on a whim. LK (that’s Anant without the ‘h’) says, on email that he thinks my calculations were wrong. He sent me this figure to make his point:

You should be able to check that the probability from that figure is closer to a third than to a sixth. This is proof positive that I was wrong, and that LK’s answer in the comments on the last post was right (although there still is no (120-t) in any denominator).

I am usually willing to be shown wrong, and to accept it when I am. Here, though, I couldn’t stop myself – out of disbelief, mostly – from writing my own test on MatLab, and re-doing the expression for the probability; correctly, this time.

Here, first, is the expression for the probability, in terms of ‘m’, the time I spend in the mess, and ‘n’, the time Avani spends in the mess. The first line simplifies to the second

The MatLab code I wrote is here, so you can check the results for yourself.

I’d averaged the second terms in each bracket as (m/2) and (n/2) respectively, the last time. Obviously, that’s the wrong thing to do. The expression above gives an answer that is close to, but not exactly, what LK got. The MatLab simulations also give similar probabilities. I can’t explain what is causing the discrepancy between the expression and LK’s vastly more understandable graph. Maybe LK will help.

Random Probabilities: How long do you eat?

[The calculations I’ve written down here are wrong. Go here for the correct answer and a discussion.]

I have this friend who, for the most part, did no maths in her undergrad. So although she’s quite the nerd, she’s hopeless at maths… so far. We’ll see if that doesn’t change.

Both of us eat with people from our own labs, and those schedules seem to be self-determined and uncorrelated (except for beginning within the two hours of lunch – there’s a subtlety involved here, which I’ll come back to). I asked her, as part of a deal, to predict what the chances that she’d run into me were, if she wanted to hand over her hard-drive for the TV shows she wanted (House and TBBT, if you’re curious. I said she was a nerd!). If the problem seems like it’ll be uselessly simple, I obviously didn’t write this for you. Also, do read through. There’s more than one version.

Let’s say we’ll both be at the mess for 20 minutes. What are the odds that our lunch times will overlap? If you’ve done the arithmetic in your head, did you get one-sixth? (I said two-hour lunch break, remember?)

Or more accurately than last time, let’s say I eat for 15 minutes, while she eats for 25. What are the odds now? Would you be surprised if I told you they are the same as before? (Do you know how to get this? I’ve written it down in white at the end, just in case.)

Now, we’ve assumed in the above that the mess will let you keep eating for as long as you might take to finish if you made it to lunch before the two-hour mark. What if the mess requires that you stop eating at 2pm – end effects, if you want? It’s straightforward to account for those, now that I’ve told you.

One last case: what happens if, like in the bus-stop case, the time I take to eat lunch varies within certain bounds? How about if that’s true for both of us? I haven’t done the arithmetic for this (mostly because I just made this part up), but I’d imagine that it’s doable. (I should also think the answer won’t change, if the mean-times don’t. I’m not sure.)

Okay, here’s the answer to the unequal eating times case (I hope you tried doing it before looking here):

There are only two possibilities regarding who’ll be at the mess first (the same-time case is just a degeneracy of these), and both are equally probable. If I get to the mess first, she has 15 minutes to get to the mess before she won’t meet me. If she gets to the mess first, I have 25 minutes before I won’t meet her. Mutatis Mutandis for ‘m’ and ‘n’ minutes respectively. It’s the average of ‘m’ and ‘n’ divided by the two hours of the lunch break that’s the answer.

[Ananth pointed out a flaw in the above answer, in the comments here. There are end-corrections even when people are allowed to keep eating after the 2 hour mark. If you take those into account, the probability is lesser than (m+n)/2T. The correction can actually be written down algebraically in terms of ‘m’ and ‘n’. For 15 and 25 minutes, respectively, the probability of interest is 0.152, for example, and not 0.1667.]