Archive for November, 2011

Fault-tolerant discovery!

November 28, 2011

Michael Nielsen’s piece (Some) garbage in, gold out is the must-read of the day; to give you a flavour, here are some excerpts from the piece:

How many people have truly mastered quantum field theory, statistical inference, detector physics, and distributed computing?What, then, should we make of any paper announcing that the Higgs boson has been found?

Standard pre-publication peer review will mean little. Yes, it’ll be useful as an independent sanity check of the work. But all it will show is that there’s no glaringly obvious holes. It certainly won’t involve more than a cursory inspection of the evidence.

When discoveries rely on hundreds of pieces of evidence or steps of reasoning, we can be pretty sure of our conclusions, provided our error rate is low, say one part in a hundred thousand. But when we start to use a million or a billion (or a trillion or more) pieces of evidence or steps of reasoning, an error rate of one part in a million
becomes a guarantee of failure, unless we develop systems that can tolerate those errors.

It seems to me that one of the core questions the scientific community will wrestle with over the next few decades is what principles and practices we use to judge whether or not a conclusion drawn from a large body of networked knowledge is correct? To put it another way, how can we ensure that we reliably come to correct conclusions, despite the fact that some of our evidence or reasoning is almost certainly wrong?

Or think of the loss of the Mars Climate Orbiter. That’s often described as a failure to convert between metric and imperial units, which makes it sound trivial, like the people at NASA are fools. The real problem was deeper. As a NASA official said:

People sometimes make errors. The problem here was not the error [of unit conversion], it was the failure of NASA’s systems engineering, and the checks and balances in our processes to detect the error. That’s why we lost the spacecraft.

In other words, when you’re working at NASA scale, problems that are unlikely at small scale, like failing to do a unit conversion, are certain to occur. It’s foolish to act as though they won’t happen. Instead, you need to develop systems which limit the impact of such errors.

In the context of science, what this means is that we need new methods of fault-tolerant discovery.

… one useful source of ideas may be systems and safety engineering, which are responsible for the reliable performance of complex systems such as modern aircraft. According to Boeing, a 747-400 has six million parts, and the first 747 required 75,000 engineering drawings. Not to mention all the fallible human “components” in a modern aircraft. Yet aircraft systems and safety engineers have developed checks and balances that let us draw with very high probability the conclusion “The plane will get safely from point A to B”. Sounds like a promising source of insights to me!

Have fun!

Coping with temperature fluctuations

November 18, 2011

How do plants manage to deal with temperature fluctuations? A nice commentary.

Meaningful bilingualism

November 8, 2011

Ram Guha on the English question:

A century after Gandhi and Polak debated the question in Johannesburg, arguments about the relevance of English to India and Indians continues. The debate has moved on, of course, since society and history have moved on too. One might foreground three significant changes since Gandhi’s time. First, there are now far more inter-community marriages, particularly among the middle and upper classes. And if a Gujarati marries a Tamil, or a Bengali weds a Malayali, then the default language of their children, and of the family as a whole, tends to become English. Second, although Britannia no longer rules the waves, English continues to be the major global language, its pre-eminence a consequence of America having replaced Great Britain as the great imperial power of the age. Whether spoken in the queen’s diction or in its American or other variants, over most of the world English thus remains the language of choice for communication between people of different nationalities.

The third change is, in the Indian context, arguably the most significant. This is that there is now a real hunger for English among the poor. As many readers of this column will know, from their own experience, domestic servants are determined that their children will not follow them into their profession. They recognize that the best way to escape hereditary servitude is for their children to learn the language of mobility and opportunity, which of course is English. The desire to learn English thus runs deep among all castes and communities. Poor Muslims are as keen to learn the language as are poor Dalits or adivasis.

Whether one approves of it or not, this rush to learn English is unstoppable. Rammanohar Lohia and his followers have lost the battle to banish English from the imagination or learning experience of the Indian child. That said, one might still wish for a sort of historic compromise between the positions articulated by Gandhi and Polak. We live in a land of a quite extraordinary diversity of linguistic and literary traditions. And yet in practice we tend to privilege one language at the expense of all the others. That so many middle- and upper-class Indians speak only English is a shame; that so many subaltern and working class Indians do not have access to decent education in English is equally a shame.

A nice piece. Take a look!