5.4 A brief history of scientific revolutions
We now go on to look at the history and traditions of scientific discovery. As an early years practitioner, you will find this survey useful in helping you to challenge the prevailing perception of science as ‘absolute truth’.
What we call science was once regarded as ‘magic’, ‘alchemy’ or ‘conjuring’. Such knowledge was viewed as ‘black magic’ and feared as a satanic art (Woolley, 2002). In part this may have been because, in the Middle Ages, scientific ideas were emanating from the Arab world: Christian Europe saw such ‘heathen’ knowledge as ‘evil’ and therefore to be discredited and feared. But these early activities gave rise to major scientific discoveries: for now we will focus on just one – the organisation of the planets in our solar system.
Some 2,000 years before the birth of Christ, the ancients were using arithmetic to solve problems. The ancient Greeks (c. 585 BC), in particular, were well-versed in astronomy: Anaximander of Miletus (c. 610–546 BC) postulated that the earth was shaped like a cylinder and the sun was twenty-seven times larger than the earth; Aristotle (384–322 BC) and, later, Ptolemy (c. AD 85–165) both believed that the earth was at the centre of the universe and that the sun revolved around the earth (Russell, 2000). Then came Copernicus, Kepler, Galileo and Newton – four giants of scientific discovery, on whose work much of modern science is based.
Living and working in Poland, Nicolaus Copernicus (1473–1543) was the first to publish a treatise on the heliocentric universe (i.e. as sun-centred, with the earth and other planets travelling around it in a perfect circular motion). However, Copernicus was a cautious man: he knew that the church would have him tortured and executed for heresy for his ideas, so he instructed his assistant, Rheticus, to publish his treatise only when he was on his death-bed. But why was this heliocentric view of the universe so contentious?
If you look at the sky, what do you see? The sun rises in the east, travels across the sky and sinks in the west. To the senses, it looks as though the earth is standing still while the sun moves around it. This is what Aristotle and Ptolemy saw, and certainly it was what the early Christians saw and believed. Their perception was strengthened by an interpretation of the Bible which depicted the earth in the middle and the heavens above, perfectly fixed by God who lived there while he governed his mechanical universe (see Figure 1). This geocentric (earth-centred) view of the world was theologically, socially and politically obligatory at this time; to challenge it was to risk death.
In Florence, Galileo Galilei (1564–1642) read Copernicus's work and set about using a new invention, the telescope, to view the ‘heavens’. He saw that Copernicus's heretical heliocentric theory actually made sense. In 1638, Galileo wrote about ‘this universe, which I with my astonishing observations and clear demonstrations had enlarged a hundred, nay, a thousandfold beyond the limits commonly seen by wise men of all centuries past…’ (Sobel, 2000, p. 371). His telescopic observations, which enabled him to confirm Copernicus's premise, is an example of what Kuhn (1970) describes as a ‘paradigm shift’, from an old-normal science (geocentricism), through a revolution, to a new-normal science (heliocentricism).
In 1616, the Pope sent an ‘inquisitor’ to reprimand Galileo and warn him to suspend his activities immediately. Galileo realised what could happen if he crossed the Pope and wisely retracted his theory, saying that the movements of the heavens were exactly as described in the biblical Psalms. However, he continued to make his telescopic observations and, when the political climate improved with a change of Pope, he published his new work.
In Prague, Johannes Kepler (1571–1630), astronomer to Emperor Rudolf II, read Galileo's work and was able to confirm it. He did so without fear of execution because, in Prague, supreme political power lay with the Bohemian emperor and not the church. Kepler refined Galileo's observations by showing that the planetary movements were not perfectly circular but, rather, were elliptical.
However, Kepler's work presented some problems. From Poland, England, Prague or anywhere else in Europe at this time, if you looked unaided at the sky, you could not see anything that proved the heliocentric view of the universe – it was a counter-intuitive theory. The other huge obstacle to its acceptance was that if the earth was moving rapidly through the heavens – as it must surely do if it was travelling around the sun and spinning on its own axis each day – then why did things fall straight down when they were dropped from a great height? The problem was resolved by the work of Isaac Newton (1643–1727).
Newton formulated his theory of gravity (or ‘law of universal gravitation’) while studying theology at university: illness had interrupted his studies, and he had begun to dabble in science. Newton is known today as ‘the father of scientific method’ because he developed the concept of the controlled experiment for testing or falsifying hypotheses: all modern science is based on this methodology. A controlled experiment is one in which a ‘control condition’ is compared to another, the ‘experimental condition’, where one variable has been changed. Newton performed a simple experiment to show that a stone, dropped from a height, would fall straight downwards and not land at an angle: from this and other work, he was able to formulate his theory of gravity. (The story about apples falling on his head is almost certainly untrue, although it was told by Newton himself.)
But problems remained. The number of known planets was increasing and their orbits appeared, generally, to go along with Newton's predictions – but not with complete accuracy as there were seemed to be some small variations in the elliptical orbits. A couple of centuries after Newton, Albert Einstein (1879–1955) was able to solve these problems with his theory of relativity, bringing about another scientific revolution and generating much excitement in the newspapers of the day! The London Times headline of 7 November 1919 reported: ‘Revolution in science – new theory of the universe – Newtonian ideas overthrown’ (O'Connor and Robertson, 1997).
Einstein's theory of relativity asks us to think of time and space as aspects of the ‘same thing’. We used to think, and our senses continue to tell us, that space is experienced directly and can be measured in three dimensions – height, length and width – while time is altogether another sort of thing that is experienced through our memories and measured with clocks. However, according to Einstein – and this was the big paradigm shift or revolution – time and space are on the same continuum and are relative to each other. Falsifying Einstein's theory is what scientists are grappling with today (Chalmers, 1978).
Table 1: A summary of the changes in human understanding of the universe