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Thursday 9 June 2011

Galileo and method

Western science is believed to have begun with Galileo when he or his friend dropped two objects of unequal masses from the leaning tower of Pisa in Italy. It is said that in this so called experiment with which Galileo is credited with giving birth to the experimental method, it was shown to the world, at least to those who were present in Pisa on that fateful (or faithful?) day, that bodies of unequal masses dropped from the same height at the same time fall to the ground simultaneously. However, Galileo or his friend did not drop those objects in a vacuum, and he could not create a vacuum around the leaning tower. If a feather and a ball made of iron were dropped from the leaning tower it is quite clear that the ball would have beaten the feather by several minutes. A pundit would say that it is due to the air resistance that the feather takes a long time to reach the ground and if the experiment was done in a vacuum the ball and the feather would have reached the ground simultaneously.

However, what we have to remember is that no vacuum was created around the leaning tower and Galileo left it to the imagination of those who were present to assume that there was a vacuum surrounding the tower. Galileo did not use a feather and a ball as described above in his experiment since if he did so he would not have been able to convince the others. He “constructed” an “apparatus” to demonstrate what he wanted to show and that was the beginning of the experimental method as described by the western scientists and philosophers of western science. What the western scientists would not say is that the people in Pisa on the day of the “experiment” did not see objects falling in a vacuum though they were made to believe that there was a vacuum that has been created by Galileo or somebody else. What Galileo performed in Pisa could be described as a thought experiment as it happened in the imagination of the people.

Of course, the concept of force had not been formulated in the days of Galileo and very few would have imagined air resistance as some sort of a force acting on bodies such as feathers whose densities are low. In any event it cannot be said that the Aristotelian view that was the dominant “theory” before Galileo on falling bodies was mere speculation. The “theory” that if dropped at the same time from the same height, the heavier body falls to the ground before the lighter body is based on observations. It is known that bodies such as iron objects fall to the ground faster than bodies such as feathers. This feature had been observed from time immemorial and no one would have objected to it, and would have been taken as a matter of fact based on observation. In that sense observations had been there prior to Galileo even in Europe. The rest of the world, especially China and South Asia were much ahead of Europe at that time (even today) and in Bharath an experiment had been carried out to determine whether an Athma (soul) escaped from the body after the death of a person. The experiment was very cruel as the Brahmins had killed a person, probably a shudra, to find out whether there was an Athma. Naturally they could not come to any conclusion as they did not observe anything going out of the body after the person was dead.

If Galileo was to conduct this “experiment” he would have concluded that something escaped from the body and that there is an “Athma”. He could have argued that we only observe what can be observed and that there are things that cannot be observed and since Athma is something that cannot be observed we could not observe anything escaping from the body of the dead person. If one finds this “argument” ridiculous then one does not know that Galileo showed that the Earth was moving using a similar argument. The essence of the argument is that one observes what can be observed and even if one does not observe something it could be present or is present as it is something that cannot be observed.

The “knowledge” that the Earth moved around the Sun was in Bharath long before Copernicus “discovered” this fact. They would have obtained (constructed) this knowledge through Bhavana and Yoga exercises closing the five sense organs (pancendriya). However as far as people in Bharath was concerned it was only a relative knowledge and not an absolute knowledge as in Astrology they continued to use the Earth centered frames of reference, if I may use a phrase introduced in Newtonian Mechanics. It should be stated that even today there are people in Sri Lanka who gain knowledge through Bhavana and I am of the view that it is the method that had been used by the Sinhala Buddhists to “acquire” knowledge though acquiring as such is not going to help one to attain Nibbana. When the knowledge that had been there in Bharath went to Eastern Europe Copernicus was convinced of it and took that knowledge to Italy when he went there to be trained as a Catholic priest.

Galileo took over from there and began to teach the so called Solar centered theory in Italy. The Pope naturally objected to it as nobody observed that the Earth went round the Sun. All that the people observed was the rising of the Sun and its setting and one could have said that to assume that the Earth moved round the Sun was against the experimental (observational) method. The Pope asked Galileo not to teach this nonsense of the Earth moving round the Sun unless he could prove it to the others. The Pope objected only to teaching but he allowed Galileo to believe it if it was his wish. I think the Pope had been very reasonable compared to some of our so called scientists in Sri Lanka, who are basically sample collectors following set procedures and technicians testing for various substances using known methods. None of these scientists have ever come out with a new theory or a concept but may have published hundreds of papers in so called internationally renowned prestigious journals having done the work of sample collectors and technicians. However these people whose experimental method is confined to mere observations hanging on to what are known as controlled experiments especially in the Biological Sciences object vehemently to knowledge gained through Bhavana. Most of these experimentalists would not have heard of the thought experiments of Galileo and especially of Einstein.

When Galileo was asked to prove his theory (it’s neither his theory nor that of Copernicus but Bharath Theory) he did not engage in either Bhavana or Yoga exercises (respectively Buddhist and Hindu methods of gaining knowledge) and had to resort to abstract thinking. Probably both Galileo and Copernicus and some others in Eastern and Southern Europe at that time had an intuitive feeling that the Earth went round the Sun rather than the other way around and had no difficulty in believing the new theory. However, for the rest of the people who depended on their pancendriya, like the good Pope, there was no reason why they should believe that the earth went round the sun. Besides, they had strong evidence to show that the earth did not move. Their argument was very simple. An object dropped from a certain height takes a non zero time to reach the ground. If the earth moved, during this time the point on the earth just below vertically the point from which the body was dropped would have moved away resulting the body dropped to fall at a distant point. For example a coconut would fall to the ground at a point away from the coconut tree probably in the neighbour’s garden if not on the roof of his home.

Now Galileo had a problem. He had to explain why the bodies fell vertically. After all the balls he or his friend dropped from the leaning tower fell vertically defying the theory that the earth moved. Galileo came with an ingenious argument. He introduced the so called concept of relative motion. According to him the dropped objects moved horizontally (parallel to the earth) with the earth, as they also had the same horizontal velocities being connected to the earth through the person who dropped them. Thus the horizontal velocities of the objects relative to the earth were zero. Galileo said we observe only non zero velocities relative to us. The only non zero relative velocities of the objects that were dropped were their vertical velocities and hence we observed only their vertical motion. We do not observe their horizontal relative velocities but that only means that they move with the same velocities as the earth. Therefore the earth moves or at least nobody could say that the earth does not move.(2011/06/01)

Copyright Prof. Nalin De Silva