As strange as it may sound, modern science is not directly concerned with reality, but rather with models of it. Reality is the realm of philosophy. The essence of science is the scientific theory, whose purpose is to provide coherent explanations to observations; an objective aptly summed up by the physics Nobel laureate, Richard Feynman (1918–1988):

No one has ever seen the inside of a brick. Every time you break the brick, you only see the surface. That the brick has an inside is a simple theory which helps us understand things better. The theory of electrons is analogous … The electron is a theory that we use; it is so useful in understanding the way nature works that we can almost call it real.

Although theory is at the heart of science, not every theory is scientific. For a theory to be scientific it must first be internally consistent, that is, it should lead to no logical or mathematical paradoxes. If, for instance, a theory could lead to a conclusion that an object may simultaneously exist in two different places, the theory would not be consistent and cannot be deemed scientific. (This example is a paradox that contradicts the principle of space and time: a physical object exists separately in space and time in such a way that they are localizable and countable.)

Unlike mathematical models – which being the creation of the human mind require internal consistency only ¬– scientific theories based on these models must also be testable: that is, it does not matter how elegant or internally consistent a theory may be, if it does not agree with observations external to the theory, it is wrong. This requirement means that a theory can be considered scientific only after test criteria can be defined. That is, every theory is potentially refutable. Contrary to the common belief, turning scientific does not necessarily improve a theory or make it more reliable, as it may often lead, inadvertently, to the refutation of the theory;

It was not surprising that evolution theory had evoked passionate antagonism. Its radical implications were far more reaching than the “we are not monkeys” emotional response. The theory eliminated the need for a designer or a creator, and it undermined what was probably the oldest and most frequently used proof for the existence of God, as first expressed by the ancient Roman Marcus Tullius Cicero (106– 43BC):

When you see a sundial or a water-clock, you see that it tells the time by design and not by chance. How then can you imagine that the universe as a whole is devoid of purpose and intelligence, when it embraces everything, including these artifacts themselves and their artificers?

Those who object to the evolution theory can be broadly classified into two camps: creationists, and the advocates of intelligent design, also known as design theorists. Creationists believe that the literal biblical narration provides a factual account of events, and reject any kind of evolutionary process. Intelligent design, on the other hand, accepts that organisms could evolve from other organisms, but rejects the randomness of the process and suggest that it was preordained and following a blueprint. To use an analogy, when dominos fall, although each piece falls because it is pushed by its predecessor, the pattern of the fall is predefined by the original setting of the dominos.

Intelligent design theorists claim that without such a blueprint, biological organs and systems that display irreducible complexity could not have evolved. That is, no random process could account for the development of an organ, like the eye, which is composed of several interacting parts, all required for its functioning. As evolvement of anything but the complete operating organ could not function at all, it would not have survived the process of natural selection.

It took Darwin many years and many attempts to find a theory that could answer the many questions that perplexed him during his voyage. His theory could explain why fossils of extinct animals carried a close resemblance to existing species, and clarified why each of the Galapagos Islands had its different but very similar species of animals. It also accounted for the existence of creatures that, in Darwin’s view, could never be designed by a benign entity, like the parasitic wasp, which stored caterpillars to be eaten alive by its grubs.

Modern evolution theory has evolved considerably since Darwin’s days. However, regardless of the major changes the theory has undergone, the new body of evidence, accumulated from otherwise unrelated fields of science, only strengthen its plausibility. While unlocking the secrets of DNA revealed the engine behind the random variations, microbiology gave empirical evidence that not only do such variations occur regularly, but that they directly impact on lives, as both the cause of new diseases (e.g. aids, bird-flu) and the means for their cure.

Further evidence has been derived by paleontologists and evolutionary molecular biologists, who have been able to fill many of the gaps in the history of species. Evolutionary molecular biology provides us with the tools to measure the amount of DNA change that differentiates one species from another. This has led to the surprise discovery that the difference in the DNA sequence between human and chimpanzee is no bigger than 2%. Humans were no longer the crown of the creation, but the result of random changes that happened to make them better adapted for survival – Aristotle’s scale of value had lost its meaning.

Unlike physics and astronomy, in which unbiased observation directly contradicted religious teachings, for a long time progress in biology did not challenge old wisdom. Throughout the 16th and 17th centuries biologists classified all known plants and animals into taxonomical groups, and were, therefore, well aware of the commonalities living organisms shared. Yet, the belief that all living organisms had been created in their current form was so well rooted that no serious alternative existed before 1859. This was the year that Charles Darwin shocked his contemporaries by implying that humans and animals shared a common ancestor.

In 1831, Charles Darwin (1809–1882) joined as a naturalist the survey ship HMS Beagle for an expedition around the world. When he returned home in 1836 with over 2000 pages of notes and thousands of skins, bones and fossils, his work had just begun. It took over 20 years before he finally formalized his findings and observations into a consistent theory, which he published in his book On the Origin of Species by Means of Natural Selection.

Natural selection theory suggests that adaptation to the environment, through the survival of the fittest, is the main (though not the only) mechanism of evolution. Random variations continuously occur in species, which are constantly under struggle for resources. When “the surviving one of ten thousand trials” gives an organism an advantage in its environment, it would pass on this favorable change to its offspring. Accumulation of such variations within a population, particularly when major environmental changes occur, could eventually lead to the creation of new species.

The heated debate over the working of the universe, we have discusssed so far, had little relevance outside the scientific and theological communities. Whether it was the sun or the earth at the center of the universe, or what laws falling bodies obeyed, it made no difference to people’s faith. The new discoveries diminished neither the splendor of the creation nor the greatness of the creator. For most people, religious teachings were about how one goes to heaven, and not how heaven goes.

This attitude still prevails nowadays, when even the most religious of people do not expect their religious practices to explain nature, and are happy to leave these ponderings to science. In all areas, that is, but two: the age of the universe and evolution.

According to Genesis, the world was created in six days, and by counting the generations in the Bible since Adam and Eve, theologists concluded that the creation took place some 6000 years ago. This figure is supported by the Jewish calendar, which is believed to commence from the first day of the creation. Contemporary mainstream scientific theory, on the other hand, draws an entirely different picture. It estimates the age of the earth at about 4.6 billion years, and that of the universe at over 13 billion years.

Interpretations of the text in Genesis which aim to address this dichotomy have been around since the 19th century. A common explanation was that the Bible, speaking to the ancients who could not comprehend numbers like a million or a billion, did not speak of a ‘day’ (yom in Hebrew) as a period of 24 hours, but rather in a metaphorical way as an unspecified duration of events which could last thousands, millions or even billions of years. (By the way, such big numbers could not be written, let alone understood, before the introduction of ‘0’, which happened around the 7th century in the Arab world, and 13th century in Europe.) Alternative interpretation suggests that the six-days in Genesis do not represent the time of the creation itself, but a six-day period during which God revealed the truth of the creation to Moses on Mt. Sinai.

Despite the various interpretations, many are still adamant that the literal interpretation of the Bible is correct, and that the problem lies with science. They point out that unlike the previous conflicts mentioned, the age of the universe cannot be found by observation or any other direct method, but is deduced from a combination of complex theories with many underlying assumptions. They claim that as theories change frequently they cannot be trusted, and in the end, scientific theory will discover that the biblical age of the universe is correct.

Regardless of future scientific development, this dispute – just like those mentioned previously – threatens only human interpretation and not faith itself. Six days or 13 billion years, it leaves the magnificence of the creation intact, as it does the need for a creator. This, however, is not the case with the theory of evolution, which threatens not only the role of God, but also Her very existence.

While the new scientific way of thinking (as described in my previous posts) was partially responsible for the decline in the power of the Church, the resultant image of the world neither threatened the fundamentals of faith, nor replaced the need for a creator. For many scientists, revealing the nature of the world was the way to understanding the creation and the glory of God. Copernicus, Galileo, Kepler and Newton, were all devout believers who saw their scientific work as a religious undertaking. For example, Kepler wrote in his Harmony of the Worlds:

Geometry provided God with a model for the Creation and was implanted into man, together with God's own likeness. ... It is absolutely necessary that the work of such a Creator be of the greatest beauty.

Although these scientists were aware of the objections their work would provoke, they did not consider the new discoveries to contradict religious teachings. They held the view that the scriptures, written for everyone to understand, were not to be taken literally. Any contradiction between religious teachings and the scientific discoveries was due to human’s mistaken interpretation. They believed that correct knowledge of the cosmos would provide a better insight into the scriptures, and that it was our pious responsibility to reinterpret the texts to match the known facts, as there should be no inconsistency between science and the scriptures when they were rightly understood.

Standing upon the shoulders of giants, it was the British physicist Sir Isaac Newton (1642–1727) who finally replaced the Aristotelian model of the universe. His law of universal gravitation and the three laws of motion laid the cornerstone for modern physics, and provided a single set of laws that governed both earth and heaven. There was no need for two set of rules any longer, and the ‘corrupt’ transient earth and the perfect eternal heavens were now obeying the same laws of nature. The workings of the universe became the realm of science.

Kepler's contemporary, the Italian scientist and astronomer Galileo Galilei (1564-1642), in his most renowned experiment dropped two bodies of different weights from the Leaning Tower of Pisa, and clearly demonstrated that all bodies fall at the same speed regardless of their weight. This was indisputable proof that Aristotle's theory and the Church's dogma were fundamentally mistaken. Galileo also revolutionized astronomy when he was the first to apply the telescope to the study of the heavenly bodies. His observations led him to discover the moons of Jupiter and the phases of the planet Venus, and convinced him that Copernicus' heliocentric model was right. In 1633, Galileo was brought before the Inquisition for a grave suspicion of heresy. He was forced to formally renounce his beliefs, and was sentenced to life-long house arrest.

Claiming that the sun was at the centre of the universe, Copernicus directly challenged the Church's sacred worldview, which was based on the Aristotelian model. He was the first to challenge, but what he started was unstoppable, and many followed.

Johannes Kepler (1571-1630), a German astronomer, developed the Copernican model into his three major laws of planetary motion, which are still in use nowadays. These mathematical laws could accurately account for all planetary observations. However, by suggesting that the planets were moving in elliptical orbits around the sun, and not in the heavenly perfect circular motion, Kepler deviated even further from the Aristotelian model that was the base for the worldview of the Church. He was excommunicated from the Lutheran Church in 1612

As we have seen in our last posting in this blog Copernicus, who postulated a model in which the sun was at the centre of the universe. knew that the clear advantages of his model would not protect him from the hostile reaction of the orthodox authorities and the Inquisition, and it was not until 1543 – the year of his death – that he eventually published his complete work On the Revolutions of the Heavenly Spheres.

It is clear from the extent of the criticism of his work that Copernicus challenged not only the knowledge of the cosmos, as portrayed by the church, but he challenged knowledge itself: Should our impartial experience determine our understanding, or is it our knowledge that the world should conform to?

For example, Tolosani, a contemporary of Copernicus, wrote:

[Copernicus] seems to be unfamiliar with Holy Scripture since he contradicts some of its principles, not without the risk to himself and to the readers of his book of straying from the faith. ... in his imagination he changes the order of God's creatures in his system. ... he seeks to raise the Earth from its lower place to the sphere where everybody by common consent correctly locates the Sun's sphere, and to caste the sphere of the Sun down to the place of the Earth, contravening the rational order and Holy Writ, which declares that heaven is up, while the Earth is down.

It was most likely, therefore, that the Church would have condemned Copernicus’ work, had it not been for an introduction inserted by the publisher. The introduction stated that the book merely presented a simpler way to calculate the positions of heavenly bodies, and that “the hypotheses contained within made no pretense to truth that, in any case, astronomy was incapable of finding the causes of heavenly phenomena.” This unauthorized insertion, although appalling to many, ensured the book was not immediately condemned. In fact, it was publicly available for over 70 years before it was subject to censorship.

Although some were sentenced to death for their support of Copernicus’ heliocentric system (for example, Giordano Bruno was burnt alive in 1600) it was not until 1616 that the Church placed the work on the List of Prohibited Books (Index Librorum Prohibitorum) and decreed that “the propositions that the Sun is immobile and at the center of the universe and that the Earth moves around it, judging both to be ‘foolish and absurd in philosophy,’ and the first to be ‘formally heretical’ and the second ‘at least erroneous in faith’ in theology.” By then, however, Copernicus’ mathematics had already been widely in use, and although many still viewed it as a hypothetical calculation model, it was unavoidable that questions about the nature of the cosmos as derived from the model would arise.

The scientific revolution had begun.