Science and Reason

Science and Reason: A historical journey in science and its methods

Here is a story as recounted by Meghnad Saha, one of the pioneers of modern astrophysics. The episode took place in his village in the late 1930s. His father's friend met Saha and asked, “I hear that you have become very famous for your science, may I know what it is all about?” Saha described to him his work on thermal ionization equilibrium in stars and its relation to stellar spectra. The gentleman listened and then said, “But that is all given in the Vedas.” Taken aback, Saha further described the 20^th century revolutions in science related to atomic structure, relativity etc. The gentleman persisted: “All these are given in the Vedas.” Saha narrated again how knowledge had developed through a tortuous path -- the Copernican revolution of 16^th -17^th century Europe, contributions by Galileo, Kepler and Newton, etc. He also talked about the contributions of ancient Indian mathematics. He explained how, important as these contributions were, they could not have led to the revolution that we saw in the Copernican era. But the gentleman remained adamant and persisted that all of modern science was already available in the Vedas.

Saha wrote that he then read the Vedas to check the contention that all the findings of modern science was described in the Vedas. He, however, found no reference to them in these ancient literary books.

Here is another story. Another great scientist, Satyendra Nath Bose, narrates that after the World War I when the British built a jail in Hijli (near the location of the present day IIT Kharagpur) it was found that the site did not have a source of water. Engineers were sent to find underground sources but failed. It was rumoured that a local ‘dowser (traditional ‘water seeker’), using just a forked branch of a tree as a tool,  walked  about in the jail compound and located a source. Bose argued however that this story could not be true. He argued: “I know of Eötvös's balance and the accuracy with which it can measure the value of “g”, i.e. acceleration due to gravity. From this value of “g”, I know that the presence of oil, gas, various minerals, around a place can be found. I can understand that, on the basis of the laws of Physics. But I am also aware of the level of precision that such an instrument would demand and hence have doubts about the claims of the dowser. He further writes: “Later too, when I was a member of the Rajya Sabha, we discussed the question of exploration of underground water in Rajasthan. At that time, Delhi was agog with stories about a “Paniwallah Maharaj” who could do the job by some mysterious tricks. This Paniwallah Maharaj's services were sought. His explorations did not succeed and hence after such massive publicity.

These episodes, serve as practical issues for addressing the question of science and reason. In the first case, on being told that Copernican and Newtonian ideas of the solar system and modern ideas of stellar spectroscopy were already present in the Vedas, Saha entertained doubts. But he asserted that they were not there in the Vedas only after checking the text. In the second case, Bose had doubts about the ability of the traditional dowser because he was aware that laws of nature being universal, it would be humanly impossible to find underground sources of water by a simple device like the branch of a tree.

Methodology of science:

Science begins by questioning everything. Scientific methodology involves a level of scepticism; it is a process that seeks to arrive at conclusions about natural phenomenon by continuously raising doubts around observed events. There is a method by which this scepticism is resolved. An important lesson can be learnt if we look at a school level chemistry note book. The page is divided into three columns, experiment, observation and inference. The meanings are obvious. But the idea is to record (a) for one's own self as also (b) for the sake of others so that the experiment can be repeated, observations checked and the inference can be reasoned out, while entertaining the scepticism. These are some of the basic steps in modern science. Science, while being sceptical, accepts “universality” of scientific laws. Thus, in essence, science depends on (1) evidence and facts (2) evidence and reasoning (3) everything claiming scientific validity is put to question and test (4) anything that refuses to be put to test cannot claim to be scientifically validated.

But these were not the accepted steps, five hundred years ago. In that era, it was believed that knowledge could be obtained by the mental process of reasoning out. In the present day practice of science, exclusive reliance on mental processes are involved only in some stages of scientific work, but not all. It is first done when planning the experiment, i.e. in deciding what is to be done and in the last stage and then in the final step, inferences have to be drawn from the observations. In between the mental process goes hand in hand with doing and observing. Thus, science involves this interplay between mental reasoning and  real-life experimentation.

These processes can be long and inferences may not be automatic, at times inconclusive. In science imagination too plays a big role but it science does not progress exclusively through imagination and has to subject itself to verifiable or refutable experimental tests. This is illustrated with a few historical examples, taken from the development of science during the Copernican renaissance.

Science as a process

About our solar system, Kepler's ellipse, Copernican revolution and Newton.

We are told of Kepler's three laws on planetary motion, in our school text books. Kepler did not know about them, he found them . Our books are written in a way as if these laws came, all at the same time. The actual story is different. It took Kepler ten years to discover them and they were found one by one. The story is as follows.

Kepler was born in 1571 and went to Prague in 1600 to become an observational assistant to the famous astronomer Tycho Brahe. Tycho  died the following year and Kepler tried hard for nearly eight years to match Tycho's observations of planetary orbits to the Copernican scheme of circular paths, with the sun as the centre. He did not succeed but he persisted with the idea of circular orbits. That was because, like most people Kepler too assigned a “divine” symmetric scheme to circles and thus thought that heavenly bodies ought to follow circular paths. While the orbits of Mercury, Venus, Earth, Jupiter and Saturn fitted with Copernicus's scheme, Kepler could not fit such a circular path to the  orbit of Mars. He could put four of Tycho's Martian data points on a circle but two data points were seen to lie outside it. Only a little outside: close to a circle but not quite. Knowing that Tycho Brahe was fastidious with accuracy, Kepler could not ignore these two outlying points as being Tycho's observational errors. He got a clue from an unexpected observation. It is here that this combination of “doing and reasoning” leads us to the goal.

The idea of an elliptic orbit came to Kepler in 1604-1605, but he perfected it in 1609.  The year 1609, proved to be a momentous year in the history of science. In that year, Galileo Galilei, used a telescope for the first time for astronomical observations. This is often recorded with well justified fanfare. But one other momentous event goes unnoticed. In the same year, from Tycho's data, Kepler found that, if one considered elliptic orbits planets move slower when they are farther from the sun and faster when they are closer. With this, not only could he fit the orbit but another remarkable discovery was made by him. He found that if we join the two points P1 and P2 in the orbit of a planet and measure the shaded area “Area 1” and the time “t” taken by the planet to travel from P1 to P2, then the Areal Velocity (a/t) remains a constant for all parts of the orbit. This was a momentous discovery, to be exploited by Newton later. To anticipate what Newton would show later, these two laws proved gravitation's force to be attractive, everywhere and always points towards the sun and for this reason “angular momentum” is a conserved quantity, giving (a/t) to be a constant everywhere in planetary orbits.

Criticisms and advance:

Scepticism is a part of science. Kepler's idea of elliptic orbits was not accepted. It was ignored by Galileo and Descartes. But if Tycho's observations were to be matched, in no way could the elliptic model be abandoned. Even Kepler, the strong believer of “divine symmetry” had to give up that notion. His own work compelled him to do so. But by this time Kepler was also preoccupied with another idea, not thought about earlier. He had found that if planets are farther from the sun, they take longer time to revolve round the sun. Was there any relation between the time of revolution (T) and the planet's average distance (L) from the sun? After ten years' struggle, Kepler found the relation to be : T² is proportional to L³. In this way, mathematics becomes the language of natural science.

How important these laws were would be proved a few years later. In the contemporary world of astrophysics, all satellites of planets are also seen to follow Kepler's laws, including artificial satellites like the Mangalyaan.

With orbit calculations important astronomical events could now be predicted. One such event to be predicted was the transit of Mercury across the sun. It was first observed by Pierre Ghassendi on 7^th November, 1631 in Paris. We have observed one such on 9^th May 2016 and the next one would occur on 11^th November 2019 and on 13^th November 2032.

Another important event would be the transit of Venus. In 1627, Kepler predicted that a transit of Venus would take place in 1631 but Jeremy Horrocks and William Crabtree with their very accurate calculations following Kepler's laws found that ANOTHER transit would occur on 4^th December 1639 - an issue that Kepler had missed. They observed this transit with telescopes. But they went a step further, they showed that this event could be used to measure the earth-sun distance, which no one had done before. They found the distance to be 99 million kilometers, a distance that no one could ever conceive of! At the suggestions of Edmund Halley, the Venus transits of 1761 and 1769 were observed from different parts on earth and the corrected value for the earth-sun distance (called Astronomical Unit) was found to be 150 million kilometers, which is very close to what we accept now. This is now one of the length scales with which astronomers measure distances.

Culmination of the Copernican revolution

Copernicus' ideas about heliocentric solar system (where planets move around the sun) appeared in 1543 and refuted the view till then of Ptolmey and others that the earth was the ecentre of the universe (the geocentric model). But the Copernican revolution took about 225 years to complete. This culmination is said to happen with the publication of Newton's “Principia” in 1687 and the return of the Halley's comet the way Halley had predicted, on the basis of Newton's laws. By studying the period and path of the 1531, 1607 and 1682 comets, Halley inferred that they were one and the same comet and would “ therefore, with some confidence predict its return in the year 1758. If this prediction is fulfilled, there is no doubt that other comets will return.” And it did.  

This revolution laid down the basis of classical mechanics, i.e. a whole host of mechanical motion, could be understood with only three laws. If you take out any one of the laws, the structure becomes incomplete and there is no fourth law.

Let us see what we can derive from them. Any modern day text book of astronomy will tell us that the sun weighs 1.91×10³⁰ kgs. The question is: how did we know that? It is known from (a) Kepler's laws, based on Newton's mechanics and gravitation (b) knowledge of earth-sun distance, (c) period of revolution of earth. All these were known by Newton's time, but Newton still did not know the mass of the sun because he did not know the value of one constant that Newton's gravitational law needed. That was the value of the universal gravitational constant, “G” (note the emphasis universal). Its value cannot be found from any amount of thinking. It has to be found from real experiments. Newton had declared the gravitational laws to be universal. So it could be found on earth too and that value should apply everywhere. This experiment was done by Cavendish in 1798. The value of “G” is very accurately known today. These days, Cavendish's experiment is repeated by students in M.Sc. level. From this value of ‘G’, we can determine the mass of the sun. That sets the mass scale for many objects in our universe. Further, knowing this value of ‘G’ and the local value of ‘g’ , i.e. the acceleration due to gravity at any point on earth, one can also predict about the existence of various minerals and oil and natural gas resources in the area. This technique is routinely used in geophysical explorations, which S.N. Bose had spoken about.

The Copernican revolution is said to have come to its completion with Newton's discovery of the laws of motion and the laws of universal gravitation. His most profound contribution was in bringing in the concept of universality to science. Newtonian mechanics would find its validity in a whole host of situations, for the next two hundred years. In the late nineteenth century, we would find that it fails in certain cases. There were observed phenomenon that Newtonian physics could not solve. It had to be replaced by the modern theory of relativity and quantum mechanics. Newtonian science was replaced but NOT rejected. Newtonian science could explain observed phenomenon that we had knowledge about in his time. As new phenomenons were observed which could not be explained by Newtonian science, a new framework was developed with the 20^th century revolution in physics.

Nature of scientific knowledge:

The history that we narrated above shows that human knowledge is in a process of evolution. Science begins with the premise that the “system” exists and knowledge is tentative. Science itself sets the boundaries within which it can claim to be correctly explain and predict natural events. The boundaries expand, giving rise to a more complete understanding.

Science is thus not a revelation of permanent truth. The truth is accepted after verification by several individuals and groups since science tries to find the “truth that is universally valid, subject to the knowledge available in a particular era. It knows that more refined truth can be discovered in future as new knowledge accumulates. Thus, what is considered to be “true” in a given era, becomes “partial truth” in a future epoch. Thus, Newton's laws in mechanics were considered to be true for about two hundred years until, its limits of validity were found in the late nineteenth century.

Does it then mean that science had been erroneously assigning a false validity to Newtonian understanding, for two hundred years? No, that is not true.  Whatever Newton had assigned are still found to be correct, but only when objects move with velocities (v) that are much less than the velocity of light (c) , or when motions take place in regions larger than atomic dimensions (a typical atomic dimension is 10 billionth of a centimetre). Such physical systems could not be conceived of in Newton's times. Neither atoms were known nor was the value of speed of light, though Galileo had contemplated that speed of light was finite and could be measured by astronomical observations.

With the advent of industrial revolution, in late eighteenth and early nineteenth century Europe, a new field, till then considered to be “dirty” appeared in the realm of science, i.e. chemistry and hand in hand arose two new professions, those of the chemist and of the engineer. These fields brought instrument-makers, blacksmiths, metal-workers, coal-miners into the “academia.” They would find means to manufacture dyes for the textile industry, tools for weaving machines, new kind of iron ploughs for agriculture and make efficient engines that would give better energy output with lesser fuel combustion. But while making these they were interested in quantification too, since without quantification these could not be achieved. These experiences made the chemist and combustion engineer look deeply into the constitution of matter itself. What emerged from there was the modern atomic theory of Dalton (in 1800) - far different, refined and more complete, from what the ancient Greeks had developed. The atomic theory was able to explain chemical properties of substances and the physical properties of gases (Boyle's law, Charles Law, Avogadro hypothesis etc.). In the process, they could establish a connection between heat and motion of atoms and molecules in substances.

This was a great leap. We had now reached a situation where immaterial of the object's motion as a whole, its parts (i.e. atoms and molecules within it) were always moving randomly with respect to each other and the vigour of this random motion would determine as to how hot the body was! This was deduced from theory, but new experimental techniques (from Doppler broadening of spectral lines) proved the theoretical predictions to be correct.

Dalton’s atomic theory was based on the understanding that the smallest unit of matter is the atom. This view received a jolt in 1897 with the discovery of the electron as a universal constituent of matter. So, the supposedly indestructible and indivisible atom, could be broken into parts: inside the atom, this negatively charged electron would have to keep the company of a positively charged central core in the atom itself. For this, it has to revolve round the positively charged core, in Keplerian orbits, since otherwise the electron would fall into the core due to attraction of opposite charges and both would vanish!

Since the time when the English physician William Gilbert (in 1600) had discovered electric charge, electricity had occupied the attention of many a scientist, but now it was to be accommodated in atomic theories. By the middle of the nineteenth century, the works by Oersted, Ampere, Faraday, Henry, Maxwell and many others, completed the conceptual foundation of electricity and magnetism. It was found that electricity and magnetism were interconnected: moving charges create magnetic effects and moving magnets would produce electric disturbances. These two always go hand-in-hand producing electromagnetic waves, that can move even through empty space (sound cannot) with the speed of light: c=300,000 kms per second (this was found independently by Foucault and Fizeau in mid nineteenth century, through laboratory experiments). It was further shown that light is an electromagnetic radiation, whose wavelength (λ and thus frequency ν, with ν= c/λ) determines the colour of light, but for all colours the speed in vacuum is the same, i.e. c = 300,000 kms/sec. Not only that, it has this unique value, no matter whether the speed of light is measured by an observer, who moves with any uniform speed in any arbitrary direction. This dictated that the old ideas of relativity, first given by Galileo, on which the entire Newtonian mechanics rests had to undergo qualitative change but would continue to maintain that laws of motion were universal irrespective of uniformly moving observers. This gave rise to Einstein's special theory of relativity, which made mass, time and length to be decided by the speed of motion of the observer. It also showed that mass(m) and energy(E) are related by a formula, E = mc², so that they are inter-convertible, as would be seen in nuclear reactions, to be discovered in the 1920's. This new theory also set a limit to the highest velocity that matter can have, that limit being c. 

 But that was not enough, a question rose: on the basis of electromagnetism, one must understand as to why heated objects turn red and then blue and finally white when they are heated more and more. It turned out that this could not be understood on the basis of nineteenth century science and one had to understand that radiation always comes out or is absorbed in energy parcels ε=hν=hc/λ. According to Newtonian ideas, energy could be transferred in any tiny amount, no matter how small. But now, we find that there was a limit as to how tiny one could make it, for nothing could be smaller than the energy quantum  ε=hν=hc/λ. This quantum character of energy transfer was found to operate in motion of electrons in atomic orbits too. According to Newtonian ideas , energy and momentum transfer could be as tiny as we wish. But discoveries in the atomic world showed that energy and momenta and sizes of atomic orbits could not be made arbitrary but had to follow certain quantum conditions, dictated by “h”, which also made things consistent with the colours of radiation that atoms emit or absorb.

All these predictions from twentieth century revolution in physics have been verified experimentally and the stage for quantitative theoretical predictions had been made ready by the nineteenth century mathematicians. When speeds are much less than the speed of light or orbits are much bigger than the atomic dimensions, results based on Newtonian science continue to hold. This can be seen, for example while dealing with situations like tides in ocean or about structure of galaxies. We must also remember that the fundamental assumptions of 20^th century Physics can be challenged in the future if and when we discover new phenomenon that it cannot explain. Science only claims that all the laws of nature are knowable but does not make predictions as to when or if ever we will know all of them.

Science and superstitions: Case of Kepler:

 It has been said, “There is a tide in the affairs of men which, taken at the flood, leads to fortune” (Julius Caesar, Act IV, Scene III). This applies to nations and to science too. At the time of the European renaissance, people took the tide at its flood, breaking the barriers of a millennium of stagnation.  But it was built up on knowledge, collected and documented over centuries, by people belonging to different societies and from different times. As Newton said: “If I have seen further, it is by standing on the shoulders of giants.”

The process has a long history. Most of the time it remains unknown and unseen as human beings struggle to live on this earth. This struggle forces us to deal with nature on the one hand and on the other to evolve the way we relate to fellow human beings as a society. In modern parlance, the first part is referred to as natural science, encompassing the living and the non living, while the second deals with social relations and is called social science.

It was through this process of struggle that early humans came to know about sunrise and sunset, tides on the seas, seasonal floods and this knowledge helped them in agriculture, e.g. to decide about the time of sowing. The calendar was provided by the night sky and the pattern of stars (with our naked eye, on a clear new moon night, away from the glare of urban lights we can see about 4000 stars), as they change with the change of seasons. This was also one of the factors that led to the development of astronomy, being driven not purely by curiosity but also by the demands of an emerging agricultural society. Thus, if the stars could predict the seasons on earth that are so crucial to our life on earth, it was neither illogical nor irrational at that time to ascribe, that our fate was decided by the stars. It was in this way that astronomy and astrology got linked to each other and the priestly class, which knew about the movement of stars got powerful as it was understood that if they knew the happenings in heaven they would also be in the know of things on earth.

It came to be believed that some astronomical events carry bad omens., e.g. eclipses, comets and meteors. It was said that “The heavens blaze forth the death of princes” (Julius Caesar: Act I, Scene II), and in this way the fortune teller gained importance. In many cases the astrologer and the astronomer were the same person. The classic case was that of Johannes Kepler, who used to earn his living by astrology. And much of the money that he earned was used in defending his mother, who was charged with witchcraft. But when it came to the discovery of the laws of planetary motion, the same Kepler did not rely on any of these claimed ‘supernatural’ gifts but purely on analysis of Tycho Brahe's data. Carl Sagan has thus commented that Kepler was the last astrologer amongst astronomers.

Scientific progress and inter-relations between societies:

Early science owes its origin in agricultural societies that flourished in the Nile valley, in Mesopotamia , in ancient India and China. Their knowledge was transferred to the Greeks, who took a fundamental step of classification and of building theories based on mental constructs. In this, fundamental contributions came from the Pythagorean and Aristotelian schools. The idea of systematizing knowledge on the basis of logical sequence gave us Euclid's geometry while the Aristotelian school gave the idea of classifying the living world in terms of similarities between flora and fauna.

This work was done by the nobility, who ruled the slave society in Greece. Slave labour allowed them the leisure, to think. They discovered ordered patterns in whatever they saw, from the sky, to flora and fauna and to the organization of Greek society, between slave owners, slaves, men, women and prisoners. This exclusively mental process led to mysticism. For example, they ended up in giving mystical properties to certain numbers and geometrical figures. These attempts at theorizing, i.e. putting the things in order and keeping them in their right place had a profound effect. It could help one to see inter-connections between disconnected things. But it also, in the end, had a deleterious effect, since this exercise in ancient Greece was divorced from practice. Thus, discovering order became an obsession and they strove to find one, even where none would exist. The nobility was disconnected not only from physical world and physical labour but also from those, on whose physical labour the nobility lived. A society, nourished by  slave labour had very little need for innovation. The nobility exploited slave labour and got whatever their lives demanded while the life of the slave was expendable.

Greek science thus soon reached its saturation and decayed into obscurity. This has also happened with science in ancient India, where the caste system, based on heredity did not allow innovation. Even after the collapse of science in ancient India and Greece, their knowledge base was kept alive by science from Arabia, Persia, Central Asia – often referred to as Islamic science. They learnt their science from from all sources: astronomy, mathematics, paper making, use of gunpowder from the Chinese, arithmetic and algebra, surgery from the India, geometry and anatomy from the Greeks. They themselves excelled in optics, mathematics, astronomy and chemistry. Whatever they learnt, they recorded them in their books. It was on this foundation that Italian renaissance stood and gave Newton the chance to stand on the shoulders of giants.

Non uniformity of developments

While European renaissance ushered in a revolution in physical sciences the real revolution in biology had to wait for two hundred and fifty years, until the publication of Darwin's Origin of Species. There was every chance that it could have preceded the revolution in physics. Thoughts about the living world had two aims, firstly in medicine and secondly in flora and fauna. About six hundred years after Hipocratus (b. 630 BC), experiments in anatomy were done by Galen (b. 130 AD). He dissected animals, mainly monkeys. This was a real empirical work but it was followed by a wrong theory. Galen and his followers advanced a notion that the same anatomical structures must be found in humans too.  This wrong idea was taken to be inviolable, until Vesalius in 1543 published the famous treatise on human anatomy (On the Fabric of the Human Body), with copious and reasonably accurate sketches, based on his real life observations obtained with dissection of human cadaver. About seventy years later, William Harvey, a student of the same Padova university, where Vesalius had studied, proved that our heart is a pumping machine, that circulates blood and heart has valves that separates impure blood from pure ones while impure blood was purified by the lungs (On the motion of heart and blood, published in 1628). Though these were revolutionary results they did not give rise to revolution in biology, for it looks that biological sciences still lacked a revolutionary theory partly because it lacked rich empirical data that astronomy had provided the physicist and also because the works of Vesalius and Harvey satisfied the immediate needs. Further, diversity and complexity of the biological world often acted as a barrier for unification, an obstacle that astronomy did not have.

 Things, however, changed with Darwin when he developed a theory called the theory of natural selection which was based on evidence. In the next hundred and fifty years we would not only examine the question of Origin of Species (published in 1859) but end up investigating the origin of life, from non living molecules! By the  time that Darwin arrived,  microscopy (pioneered by Robert Hooke, his Micrographia was published in 1665 and he coined the term, cell), had given enough information about organs and organisms; works by Francesco Redi(1668) disproved Aristotelian ( 384 BC- 322 BC) theory of spontaneous generation of life and all these had collectively given biology a footing, on which it could stand. However, the impetus for a theory came from what geologists were debating, that everything has its history and so has the earth and earth's history can be determined. One would then ask: could such a question be asked for biological species that live on earth, how did they transform with the earth's transformation? In addition, there was another question: if the population of humans grow in the way it was, would it be possible to maintain peace, if humans end up fighting each other to get their share of earth's resources? How these concerns and Darwin's meticulous observations of flora fauna and geological formations in different parts of the world led to the theory of natural selection is an interesting story that should be read separately.

Science often produces surprises and these lead people to rethink and revise views and one such example in physics has direct link with Darwin's work. This relates to Lord Kelvin, a famous physicist of the nineteenth century. He was a confirmed anti evolutionist. As a physicist, he was interested in heat conduction and tried to estimate the age of the earth from Fourier's heat conduction theory. It was known that as we go below the surface of the earth (data from mines) the temperature rises by 1ºF for every 50 ft. Kelvin assumed that the earth has a hot solid metallic core, with which it was born and it still exists in the same state in the earth's core.  So its temperature cannot exceed 8000ºF, the melting point of solid rocks. Kelvin himself measured the thermal conductivity of earth and then asked the question: how long did it take for the surface to cool to the present temperature? Then knowing that the radius of the earth was 6371 kms (first found extremely accurately by Erastothenes, 276 BC- 194 BC, and later by Al Biruni, 973 AD- 1048 AD) on the basis of Fourier's theory of heat conduction, Kelvin, in 1862, i.e. three years after the publication of Origin of Species, calculated that the earth must have been cooling since hundred million years and this is the minimum age that he could get. It was much less than what evolutionists were claiming but much larger than 6500 years that what the Bible claimed.  Kelvin was not happy with his finding. But being a scientist of unimpeachable reputation he had given precedence to his results, fighting his own dogmatism but later abandoned it when more accurate estimates came. Modern investigations tell us that the earth is 4 ±0.5 billion years old, that is more than four thousand times older than predicted by Kelvin. Then, where was the error in Kelvin's calculations? The error was in the fundamental assumption. The fact is that earth's temperature gradient is maintained by energy from radioactive decay of minerals– a fact, not known in Kelvin's time, (radioactivity was discovered in 1898 by Henri Bequerel, Pierre and Marie Curie). Knowledge of radioactive decay nowadays helps us in many historical and archaeological work, through Carbon- 14 dating and has become a standard tool (William Libby got the Nobel Prize in Chemistry in 1960, for discovering this method). The technique is now made extremely accurate so that by looking at the composition of ice at different depths of icebergs at the poles, and measuring the relative proportions oxygen isotopes (O-16, O-18), we have succeeded in getting further confirmation of global warming.

Science and superstition:

Science always sets limits to what it can explain. It does not follow a prescriptive role. This allows spiritualists to not only downplay the power of science but also to impose the authority of ‘messiahs' who know answers to all questions for all times to come: answers,  which science has not yet succeeded in giving.

The point to be noted is that by setting its own boundaries science also provides some space for speculations on the basis of unverifiable exercises, e.g. astrology. We know that the universal truth is that all living beings have to die. That is true, but science cannot tell, who will die when. But people want to be immortal. “Kim ashcharyam atapparam (what can be more surprising than this)?”asks Yudhishthira in the Mahabharata: a completely logical observation. However, this is not the logic that satisfies most of us. Even those who believe in another world and in rebirth, do not know as to what is life look like in the ‘other’ world or what would happen in the ‘next’ life here, when they are born again. It is this uncertainty that makes people seek a better one here, in this life itself i.e. in “life before death”, irrespective of what happens to “life after death”. And people tend to seek a guaranteed assurance for that. Astrology and spiritualism promise these but are based on completely untestable premises. Needless to say, they give promise but fail to provide the guarantee.

But there can be an alternative approach -- to understand worldly events from their worldly causes. Here too there may be different aims, e.g. (1) to interpret the world or (2) to change it. As PSM activists we need to do both – to look at every day experience as a way of interpreting the world, and to look for ways in which we can change what we think needs changing.