by Kamran Soomro
The clash between science and religion has existed since time immemorial. For scientists, seeing is believing. What cannot be observed, probably does not exist. Religion, on the other hand demands blind faith. God exists because somebody said He exists. Evidence plays no role in the religious thought process. By their very nature these two viewpoints are opposite and contradictory, resulting in many scientists being persecuted for challenging established religious beliefs.
Galileo Galilei is among the prominent scientists notorious for his support of the heliocentric theory that challenged the popular sentiment that the earth was the centre of the universe. For his views, Galileo was placed under house arrest and his books burned. Others like Johannes Kepler and Edmond Halley, pioneers in describing the orbits of comets and planets, too found themselves in contrast with established beliefs. It was widely believed at the time that comets were thrown in anger from the right hand of God or that they portended disaster and war. For their blasphemy, they too were persecuted.
Controversy goes irrevocably hand in hand with science, especially when attempting to explain what religion has already tried to. Theories, most notably the Big Bang and Evolution, have gone head-to-head with the religious right who cite religious texts as definitive proof of the mysteries of the universe. Those of a spiritual bent believe that scientific theories are just that – “theories” and that the holders of them will eventually see the light. Those of the scientific persuasion, state that there is ample evidence to support these theories and that there can be little doubt about their veracity. To shed some light on this debate, one must first understand how a theory is formed, what makes it a well-established theory, and how do scientists know they are right? How mere humans can be so arrogant as to challenge the word of God (presumably). What is this magical scientific process that gives them this arrogance? Or does it? Is it arrogance that leads scientists to contradict established religious beliefs, or something more tangible?
It’s important to distinguish between “scientific theory” and “theory” in the general sense. The American Association for the Advancement of Science (AAAS) defines a scientific theory as “a well-substantiated explanation of some aspect of the natural world, based on a body of facts that have been repeatedly confirmed through observation and experiment.” What this means is that there are numerous natural phenomena around us. In order to understand them, explanations are formulated on why they occur. The plausibility of the theory then depends on its explanation of observed facts while making measurable predictions that can be repeatedly tested under controlled conditions. A theory that possesses these two characteristics is a good candidate to explain the actual phenomenon. This definition also provides us with a hint about the scientific method, the application of which results in a scientific theory.
The scientific method consists of asking a question about the phenomenon being investigated, formulating a hypothesis, evaluating the logical consequences of that hypothesis, and testing these predictions. The final step in this method is the analysis of the results of the previous steps to determine if there is enough evidence to prove or disprove the hypothesis and to rule out the possibility that the evidence is observed as a random fluke. To evaluate a theory using this method, a hypothesis is chosen. This hypothesis represents some aspect of the theory and must be true if correct. There may be several such hypotheses that may be true given a particular theory. The more hypotheses are proven correct using this method, the more a scientific theory is considered plausible. A good theory is one that withstands such scrutiny over a considerable period of time without being proven wrong. For example, one question might be, “why is the sky blue?” A hypothesis might be, “elements in the air bend the light in such a way that render the light blue.” This hypothesis presents some testable predictions; there must be some elements in the air that affect the light and the light’s colour must change after hitting them. These predictions can then be tested in a laboratory to see if they support the hypothesis.
This means that there is no such thing as a completely certain scientific theory. Every theory is more or less likely. The more a theory is supported by evidence, the more likely it is. This begs the question of what happens if evidence that contradicts a theory is observed? One of two things: if the theory is still new, then most likely an alternate theory will be proposed that explains all of the previously seen evidence, as well as the newly observed one. If the theory has been extensively tested in the past, it is more likely that the existing theory will be modified slightly to explain the new facts. Generally speaking, the more a theory stands up to testing, the more confident one can be that they are on the right track.
Coming to the Big Bang, this theory attempts to explain how the universe came into being. The basic postulate is that at one point in time, the universe existed in a super-dense, super-hot state. The rapid expansion of this state allowed the super-hot energy to become less dense and cool down, giving rise to our universe. According to recent estimates, the “explosion” that caused the rapid expansion occurred approximately 14 billion years ago. Eventually, the cooled energy transformed into matter, which in turn gave rise to planets and stars. To this day, our universe is still expanding. Now one might wonder, how do you test something of this magnitude and proportion? How can you determine what happened 14 billion years ago when no planets, galaxies, suns, moons and stars existed? The sheer scale of the phenomenon is overwhelming and mind-boggling. How did humans even come to imagine such an elaborate story? What prompted the idea in the first place?
Scientists did not always believe that the universe was expanding. Initial models depicted a static universe, in which the positions of the various celestial bodies were fixed. However in 1910, American astronomer Vesto Slipher (and later others), observed that the light from most spiral galaxies was “red-shifted” which means that the observed colour of light from these galaxies was redder than it originally was. Red-shifting of light is a well-known phenomenon that occurs when the light source is moving away from the viewer. Einstein’s general theory of relativity did not allow for a static universe but predicted that the universe must either be shrinking or expanding. This led him to believe at first that his calculations were wrong. Then in 1929, Edwin Hubble discovered that relative to earth, all other celestial bodies are receding in every direction. Hubble’s calculations were found to be consistent with general relativity, causing scientists to seriously begin considering the expanding model of the universe. His discoveries later led to the development of the Big Bang model.
With the development of the Big Bang model came testable predictions. Over the years, many of these predictions have been found to be correct. Probably the most important prediction of the Big Bang was the existence of an extremely faint background glow in the universe, invisible to the naked eye. This glow is a remnant of the very early stages of the universe’s rapid expansion when the radiation was so strong, it was basically opaque light everywhere. Eventually, this light cooled and became transparent. Two American astronomers discovered this glow in 1964 – considered a landmark test of the Big Bang model and one that earned them a Nobel Prize in 1978. One might be prompted at this time to sit back and say, “Well that’s it! We’ve clearly proved the Big Bang model is the correct one, because here’s a prediction that’s come true.” Right? Not quite. The fact that one prediction was proven correct meant that scientists were on the right track, but much more testing was required before the theory could gain widespread acceptance.
As I mentioned earlier, any good theory must present several testable hypotheses. We just examined one. What about others? The Big Bang model also predicted that the distribution of natural elements in the universe must be skewed towards lighter elements like hydrogen and helium. According to estimates, hydrogen and helium make up about 74% and 24% of all visible matter in the universe. The rest of the elements only make up about 2%. These observations are in complete agreement with the Big Bang predictions. What’s more, the observed distribution of matter in the universe into galaxies and galaxy clusters is also in complete agreement with how the Big Bang simulations predicted it. The proverbial nail in the coffin, however, came with the discovery of pristine gas clouds in the universe. The composition of these clouds matches the theoretical predictions exactly.
This example clearly demonstrates how application of the scientific method, from asking questions, to developing theories based on facts, to testing these theories helps further our understanding of the universe. The point of emphasis here is that such theories are not just random guesses by scientists that they either choose to believe or discard. Well-established theories become so only after rigorous testing and experimentation. Therefore, to say that a well-established theory is just that, a theory and could be wrong is to undermine the hard work of many scientists spread across decades. This is not to say that any scientific theory is fool proof and cannot be wrong. However, given the abundance of evidence observed in its support, it is highly likely that it (e.g. the Big Bang) is mostly correct. It is still entirely possible that future evidence leads scientists to refine or alter it a little bit to better fit the facts. Science, while being transient, is still based on observed facts.
Contrary to science, religion is by definition based on the unseen. There is absolutely no evidence that can prove the veracity of any religion beyond doubt. Given this fact, it makes no sense to use religion to refute science, which is based on observable and measurable phenomena. As far as contradicting religious beliefs is concerned, that is not science’s domain. How one reconciles their beliefs with science is up to them. These are open-ended questions and I do not believe there can be one-size-fits-all answers to them. Conclusions must be individually tailored based on how one chooses to see the world.
Kamran Soomro is a post-graduate student at the University of the West of England. He enjoys reading, watching TV shows, movies and debating about science in his free time. His favourite topics include science in general, the Big Bang and evolution.