A Posteriori

Attempts to grapple with and elucidate empirical knowledge

Science: Not just a vehicle for technology January 10, 2010

Filed under: General Physics,Public Policy — Rāhul @ 00:14
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Modern life is linked inextricably to Science and Technology. Those two words, although very different in origin and meaning are so intertwined today that their history makes interesting reading. The Merriam Webster online dictionary defines Technology as the practical application of knowledge and Science as a system of knowledge covering general truths or laws that is capable of making falsifiable predictions. This definition suggests that Science creates knowledge which then propagates into Technology that is used to enrich our lives. But the relationship between the two is not always so clearly unidirectional.

2009 was celebrated worldwide as the International year of Astronomy because it was the 400th anniversary of the great Italian physicist Galileo Galilei setting about building his “spyglass” which he soon improved to discover the satellites of Jupiter, sun-spots and the phases of Venus. Galileo did all this without a scientific understanding of the propagation of light which had to wait for Isaac Newton. Instead, the technology of the telescope advanced by continued experimentation, enough for Galileo and others to gather sufficient empirical evidence for a then fledgling theory, that the earth is not the centre of the universe.

Against popular belief of the time, Nikolaus Copernicus in the 16th century had proposed that it is the earth that revolves around the sun and not vice-versa. However, it wasn’t until the preponderance of astronomical evidence gathered by telescopic observations a century later that Copernicus could be proved right. The technology of the telescope completed the most important step in the elevation of Copernicus’ proposal to the level of scientific theory. An overwhelming amount of data was gathered, all of which supported Copernicus’ idea over the model placing the earth at the center of the universe, thus convincing all rational sceptics of its merits. In this case, the advance of technology allowed us to see farther and deeper into nature’s mysteries, thus revealing scientific facts.

On the other hand, modern day technologies are inextricably linked to scientific advances. Quantum theory led to our understanding of semiconductor electronics without which the computer industry wouldn’t have taken off. General relativity allowed us to understand gravity well enough to build spacecrafts that put a human being on the moon. Enhanced understanding of the human body and the germ theory of disease led to the design of cures to many infectious diseases. Science and technology, it seems, are advancing together feeding off the achievements in each other, like a system with positive feedbacks. Improved technology allows us to probe further into phenomena that perplex us and lead to scientific theories that help design still better technologies that add value to life. But this relationship between science and technology was not always so close.

Technological advances have been a hallmark of human civilisation throughout history. Our ancestors controlled fire, learned agriculture, invented the wheel and used natural medicines, all by empirical studies that established their utility without any real understanding of the underlying principles. Despite this challenge, technology made tremendous advances, the importance of which is underscored by the fact that historians use technological strides to define particular ages of human history.

Modern Science also had a precursor in history. All ancient civilisations developed natural philosophy to explain the mysteries that surrounded them. While technologies added comfort to life, philosophical inquiry addressed the relentless questions of the mind. But these endeavours did not mesh effectively together to feed off the advances of each other like modern science and technology do. For instance, some schools of Indian philosophy postulated the atomic theory of matter long before it became a scientific theory based on empirical evidence. But the former cannot be called science because it was not based on experiments. The ancient Chinese on the other hand, made practical use of the observation that magnets always tend to align along the same direction, but they did not attempt to explain it using fundamental principles like we do now.

It was only post-renaissance that modern science, as defined by the scientific method, was born. Natural philosophy began to be buttressed by structured falsifiable experiments. Technologies increasingly made use of scientific advances and contributed to them too. This process of co-mingled development has led today to a situation where we cannot imagine excelling in the pursuit of either without also excelling in the other. But what are the consequences of this blurring of differences?

It is easy to see a causal relationship between technology and tangible benefits to society. In a capitalist economy, technological advances can be easily commercialised and the inventors rewarded handsomely. So there is tremendous societal interest in incubating and facilitating technological endeavours. But, science, on the contrary, is more of a personal pursuit. Although it leads  to technologies, its major purpose is to satisfy our innate curiosity and thirst for knowledge. While this is as, if not more, important than material progress, it is difficult to make the case for a result-oriented society to support science for its own sake, purely for the joy of exploration.

Hence, scientists in modern times have tended to use the interlinkages between science and technology and how advances in the former translate into technological marvels in attempts to win more societal support for science. While there is nothing wrong with the reasoning and it has been successful in increasing science funding, the question has to be asked if this is the right approach in the long run. By restricting the utility of science to the narrow channel of technological progress, we risk de-legitimising, in the eyes of society at large, the science that searches for answers to our basic questions.

Space exploration provides one of the best examples for this malaise. Although human beings have always yearned to unlock the mysteries beyond our earth and to go beyond the frontiers of generations past, we have now got used to justifying space missions for their perceived military or medical value. This has affected policy to such a great extent that we choose space stations that add little to our understanding or sense of our place in the universe against grander missions into outer space.

When the pursuit of science is justified in terms of technological dividends, it advances the cause of neither science nor technology. The greatest contributions to technological progress have come from science that is done for its own sake. Taking the long view to appreciate the historical differences between the two and the different purposes they serve in enriching human life can help us put today’s connections between them in perspective. The pursuit of technology and material progress is a choice. But scientific temper and understanding provide succour to the soul and is a necessity. We should be vigilant not to make support for the latter contingent on our desire for the former.

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A fair map of the world November 1, 2009

Filed under: Public Policy — Rāhul @ 13:10
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Maps seek to represent the curved surface of the spherical earth on a flat surface. All methods we have of doing this introduce some distortion or another and involve trade-offs between distortions of shapes, relative distortion of areas at different latitudes, variations in distance between points on the map which are actually equidistant and so on. Despite these issues, it is clear that maps are a valuable resource in understanding geography and increasing awareness about the world. They are more compact and easier to carry than globes and are especially well suited for representation on flat computer screens as increasingly popular internet maps are. While there are infinitely many methods of map projection, of which a few are most popular, this post is about the considerations involved in choosing the relative orientations of maps- which part of the surface of the earth will they be centered on, which directions will form the horizontal and vertical parallels and which part of our wide world will be consigned to the far left and right, split partially between those two ends.

There seems to be a certain natural reasoning behind choosing the north and south poles as two opposite sides of a rectangular map. The earth spins on a north-south axis. So, it would seem logical to have the north-south axis either horizontal or vertical on the map. The north and south poles which are distorted the most by this projection are also the least populated areas in the world, which makes the map the most helpful for most people around the world. But, the question of which part of the world the map would center on doesn’t seem to follow from any easy utilitarian argument. The alignment I have most commonly encountered in the United States is shown below in Fig: 1. I have sourced all figures in this post from the ever helpful google maps. It has the United States right in the middle and cuts through Russia, China and countries in Southeast Asia.

Fig: 1 Americas in the center

Fig: 1 Americas in the center

Understandably, this is not very popular outside the Americas. Even as an objective analyst, it doesn’t strike as particularly helpful. The two biggest oceans of the world are close to the center whereas some of the most populous regions are consigned to the far corners or ever cut into parts. Another version of the map, which is more popular in much of Eurasia is shown below in Fig: 2.

Fig: 2 Greenwich in the middle

Fig: 2 Greenwich in the middle

This map has the zero degree longitude at the center and splits at the international date line. This has the advantage of splitting the map in the pacific ocean which is the least populated stretch of the planet and which has no large land masses that are cut into two by the map. Although this map is a product of the Eurocentrism of the 19th century and reflects the primacy of the British Empire in global affairs in how the center of the map passes through London, it has the advantage of having much of the populated areas of the world towards the center of the map. A natural argument can also be made in favour of this alignment. Pangaea, the supercontinent which split to form all the current continents of the world would be left uncut by this map scheme. Pangaea was surrounded by what are today the Pacific, Arctic and Southern oceans, which this map scheme shows towards the corners, surrounding the inhabited world.

Fig:3 The human story

Fig: 3 The human story

Finally, Fig: 3 above shows another plausible map scheme which retains many of the advantages of Fig: 2, but adds a human element to the arguments. Here, the map is cut in the atlantic, which also avoids cutting through any large populated countries (except Greenland). Although the large pacific ocean is towards the center of the map, this alignment traces the migration of modern humans from Africa to populate the rest of the World. Humans crossed from Africa to the Middle East and onto Asia, Europe, Australia and across the Berring strait to the Americas. This map shows that entire route without break, which makes it an ideal candidate for a shared human map.

I do intend this only as a purely academic exercise. Maps are inherently political and are unlikely ever to be objectively drawn. Besides, with human progress I hope these issues fade away in importance rather than having to be renegotiated. Internet maps already are flexible enough to be centered at customisable places. But, that doesn’t take away from the fun of exploring what might be the pros and cons of different hypothetical possibilities!

 

Replacement and Population Momentum October 4, 2009

Filed under: Public Policy — Rāhul @ 17:53

China implemented the one-child policy back in 1979, under which most of the country’s couples were encouraged, and some would say compelled, to have only one child. Even though many Chinese parents, as decided by geography or ethnic minority status, were allowed to have more than 1 child, on the average, Chinese families had less than 2 children per woman. Indeed by 2005, the fertility rate of mainland Chinese women has fallen to about 1.75. But, China’s population continues to increase even today, as can be seen from Fig: 1 below, courtesy Wikipedia.

Fig: 1 Growth of China's population

Fig: 1 Growth of China's population

Replacement fertility rate of a group is defined as the average number of children a newborn girl needs to give birth to in her life so that the population of her group remains constant. At first glance, this number seems like it should be around 2, so that the children born would replace (at the risk of sounding rather inhumane) their parents. But, unfortunately, not all baby girls live long enough to be of childbearing age, which means the Replacement fertiliy rate has to be a little higher than 2. Also, as the sex ratio at birth in most places in the world is skewed towards boys, less than half of the children born are girls who will give birth to the next generation. So, to have the replacement number of girls, the replacement fertility rate has to be a little higher still. Obviously, since infant/child mortality rates and sex ratio at birth differ widely across the world, the amount by which the Replacement fertility rate is above 2 is different in different countries. According to Wikipedia, while the number is around 2.1 for most developed countries, it ranges from 2.5 to 3.3 in developing countries.  So, when fertility rate in China is so low, how does population still increase?

To understand why changes in fertility don’t immediately translate to changes in population, let’s see what is the immediate reason for changes in population. The net-population growth is the difference between the total of births and immigration and the total of deaths and emigration. Migrations, being independent of fertility, obviously do not affect how fertility rate affects population. Then, the question is whether replacement fertility during a particular year guarantees equality between total births and deaths. It is easy to see that it doesn’t. Even after a few years of replacement fertility, the society only guarantees that the number of births is equal to the number of births X years ago, where X is the average childbearing age of women in that society. But, the number of deaths is different! It will be the number of births Y years ago, where Y is the life span of the society. If the society had a growing population in the near past, then X would be greater than Y and so the population will continue to increase despite the achievement of fertility at or below replacement levels. Similarly, population will continue to fall for a few years in countries like Russia, which has a declining population now, even if they achieve Replacement fertility. This whole phenomenon where Population lags behind fertility rate trends is called Population Momentum.

It is evident that if fertility rate continues to be low, the Chinese population eventually has to fall. When will this happen? When the one-child policy has continued for long enough that the total number of births in the current year (in the future) is less than than the number of births Y years before current, the population will begin to fall. As births are falling each year and the number of deaths Y years ago increasing each year, that day will come soon. Of course, Chinese policymakers will find it prudent to reverse the policy, at least partially, much before that day as the dependency ratio in China is rapidly increasing, threatening to curtail economic growth as the average working age Chinese will have to support more and more retired seniors.

Policy-making is intensely intricate and dependent of good data collection and analysis. Leaving aside for another venue the morality of an overly planned state, one can’t but admire how intelligent data analysis can lead to policies that can quickly uplift hundreds of millions from poverty, as seen in China today.