Prologue

Believing with evidence

Most of us like to think of ourselves as being rational. We learned how to be sensible, logical, responsible, practical, dependable, but hopefully not cynical, as Supertramp’s Logical Song didn’t quite say.

We can think for ourselves. We can figure things out, solve problems. We take nobody’s word for it. We are nobody’s fool. Fool me once, shame on you; fool me twice, shame on me, we might say.

Of course, you wouldn’t get very far in life if logic and reason were the only things you relied on. We can’t all be Mr Spock.

In everyday life we learn to rely on a combination of things to live successfully: instinct, experience, emotions, hunches, our senses, our values, our upbringing, our judgement, our intuition and yes of course, our beliefs. In everyday practical matters, using our reason serves us well; indeed, we could hardly survive without it. Whether it’s working out our tax return, replacing the faulty tap in the garden, or putting together an Ikea wardrobe, we are always needing to reason things out. But reason needs a helping hand or two to get us through life. Reason is necessary but not sufficient.

Nevertheless, although reason is not the be all and end all of everything, when it comes to matters of faith, as with all matters, we naturally want it to be rational.

Some say there is no such thing as a rational faith. Faith means believing things without evidence they might assert. What could be less rational than that? ‘[Faith] means blind trust, in the absence of evidence, even in the teeth of evidence’ claims Richard Dawkins, the world’s most famous atheist (Dawkins, 198, 330). This book is not about faith in general, it’s about the Christian faith; but Dawkins clearly intends his definition to include the Christian faith.

To dismiss the Christian faith as ‘believing without evidence’ is more than a little ironic. It is simply not true to say that there is no evidence for Christian beliefs, or that Christians don’t care about evidence. So why insist that Christian faith means ‘believing without evidence’ when that is not what the evidence shows? Francis Collins, head of the human genome project says: ‘[believing without evidence] certainly does not describe the faith of most serious believers in history, nor of most of those in my personal acquaintance’ (Collins, 164). If one of my students came up with this definition of faith, their school report would say 'must try harder’. Actually, teachers aren’t supposed to say that sort of thing any more. Perhaps ‘works well when under direct supervision’ might have to do.

In Christianity to have faith means, first of all, to have faith in God, and to live by that faith. Of course, it also involves believing things; but then so does every other human activity. Even science, that most rational of activities, involves belief.

Scientific knowledge is the most reliable form of knowledge we possess. Nullius in verba, take nobody’s work for it, is a scientist’s motto; the motto of the Royal Society to be precise, whose fellows include Isaac Newton, Michael Faraday, Charles Darwin, William Thomson, 1st Baron Kelvin, and Arthur Eddington, all of whom will be playing a starring role in this book.  And yet, even to get started in science you need to temper your scepticism to some degree, make some unprovable assumptions, and accept some pragmatic compromises. Sometimes, even in the case of science, you need to cut things some slack in order to get anywhere. In short, sometimes, you have to start by believing stuff. Credo ut intelligam is another important Latin motto: I believe so that I may understand.

What are the beliefs that underpin science? How does it deal with complexities and uncertainties? What are its limitations? The answers to these questions will provide us with useful background ideas which we will refer to throughout the rest of the book.

Here are two of the beliefs that science relies on.

First belief: human reason is reliable (Poole, 6)

We know that in everyday practical matters reason is essential, and the only kind of reason we have is human reason, at least for the moment anyway. Computers with artificial intelligence may be catching us up soon.

Science tries to take us far beyond the everyday. Science assumes that logic, reasoning, and evidence can reliably tell us what is really true about the universe. That is certainly a reasonable assumption. 

Of course, no one thinks that human reason is infallible. Humans make mistakes all the time, and there are limits to what we can know.

Humans are often obliged to work with inadequate information. They often make false assumptions. They are prone to confirmation bias i.e. giving more weight to evidence which supports what they already think or want to believe than they give to evidence which does the opposite.

Humans make errors of logic, some of which are extremely difficult to spot. Even mathematicians need to work hard at finding multiple proofs for the same thing, just to make sure, and proofs of what Basil Fawlty would call the bleedin’ obvious. They do this partly because they know from bitter experience that sometimes things which appear to be logically obvious can turn out to be false.

In a court of law, the standard of proof is set at ‘on the balance of probability’ for civil cases and ‘beyond all reasonable doubt’ for more serious crimes; but even at the higher level of proof mistakes can be made and innocent people sent to prison.

I am not going to attempt to make an exhaustive list of the ways in which humans can make mistakes; this short list is more than enough for our purposes.

The belief here is that human reason is reliable not infallible. But if human reason is not completely reliable then exactly how unreliable is it? It is not possible to know, at least not through human reason anyway. If we try to use human reason to show how much human reason can be relied on, we are of course merely going around in a circle. Perhaps pretty much everything we think we know is wrong; it wouldn’t be the first time. It’s a possibility we cannot rule out and we have no way of working out how possible it is. We can only have faith that it is not so.

Many would say that the scientific method is the supreme example of human reason. But the belief is that the scientific method is reliable - not that it is infallible. And the method has its limits.

Here’s an example of having to work with inadequate information, a limitation about which we can do nothing. We test scientific theories using measurement. Some measurements are more precise than others, but all scientific measurements are approximate and they always will be. There is no such thing as an exact measurement. If you are dealing with whole numbers, that’s a different situation. Counting the number of cars which pass a particular place in a traffic survey, for example, will give you a whole number, and whole numbers are exact; but here we are talking about measurements of things such as length or time. Whenever scientists give the result of this type of measurement, they always include an idea of the uncertainty in the measurement; and there is always an uncertainty. A measurement is meaningless unless you quantify the uncertainty. It is possible to tell the time by looking at the ornamental sundial in my garden. I have set it to the correct time in as far as that is possible. Is that a bit nerdy? Well yes, but I’m a physics teacher; what do you expect! As a way of measuring time, the sundial is not very precise; but it is precise enough if you are just enjoying a relaxing summer afternoon in a deck chair. It gives the time to, say, plus or minus one hour. In fact, if you are busy doin' nothin', the sundial might be, well, precisely what you need.

Fortunately, since the invention of the sundial, science has produced some more precise ways of measuring time. My watch is precise to plus or minus one second. This is much more precision than I need, but unlike the sundial the watch also works when it is cloudy, it doesn’t weigh half a ton, and you can adjust it for Daylight Saving Time! In the famous Hafele-Keating experiment, far greater precision was required. In 1971 Joseph C. Hafele and Richard E. Keating, flew twice around the world, first eastward, then westward, with extremely precise atomic clocks. They compared the time measured for each journey with the time measured by atomic clocks at home; or to be more precise at the United States Naval Observatory. Einstein’s theory of relativity predicted that the times measured would be very slightly different because of time dilation. The measurements were, within the precision allowed by the clocks, in accordance with the predictions of Einstein’s theory of relativity, and they provided some impressive new evidence for the theory (Tsokos, 655). As tests for the fundamental theories of physics go, the experiment was extraordinarily good value for money. The total cost was $8000 of which $7,600 was for the airline tickets, including two tickets for the clocks. The Large Hadron Collider cost a little bit more. There are two things to note here. Firstly, the test of the theory was only possible because of the extreme precision of the clocks. Secondly, even though the clocks were extremely precise, they were not exact. If the clocks were even more precise, would they have revealed an error in the theory? Until an even better clock is invented there is no way of knowing, and even that clock wouldn’t be exact. There is no such thing as an exact measurement. There is nothing anyone can do to change this fact; it is a fundamental limitation on scientific knowledge.

A somewhat ironic example of the importance of precise measurements in the history of science comes from the famous story of Nicolaus Copernicus, Galileo Galilei, the Vatican and how it was established that the earth is not stationary, as was generally supposed in the Middle Ages, but moves around the sun. Nicolaus Copernicus developed his theory of the cosmos based on this idea in the first half of the sixteenth century. This Copernican theory eventually replaced the established theory, the Ptolemaic system, a sophisticated, and for a long time, a successful mathematical model of the universe formulated by ancient Greek astronomer Ptolemy about AD150. Ptolemy’s model was based on the idea of the planets and the moon and the sun orbiting around a stationary earth. Five planets were known to Ptolemy, the ones that are easily visible to the naked eye: Mercury, Venus, Mars, Jupiter and Saturn. The word planet is derived from the Greek word for wanderer. The positions of the stars in the sky, relative to each other, are fixed (more or less), whereas the planets change their positions over time. Seen from earth, they seem to ‘wander’ across the sky: hence the name. These positions can be measured and their movement across the sky tracked. The movements of the sun and the moon can also be carefully measured. These measurements can be compared with the predictions of a model such as Ptolemy’s to test how accurate the model is. Ptolemy’s book, the Almagest, was a big deal in the Middle Ages in the run up to the age of Copernicus.  An almagest even gets a mention in the Miller’s Tale, the famously bawdy story from Chaucer’s Canterbury tales (c.1400); not necessarily Ptolemy’s Almagest as such, but an indication that every educated person at the time could be expected to know what an Almagest was.

Since it is obvious to us now that Copernicus was right - the earth does indeed move around the sun - it is tempting to imagine that this was obvious in 1543 when Copernicus’s book On the Revolutions of the Heavenly Spheres was first published. But at the time, it wasn’t obvious at all. The fact that people did not immediately abandon Ptolemy and accept Copernicus’ theory, or even show much interest in it, is entirely understandable. To begin with, the Copernican theory did not describe the motions of the planets and the sun any better than the old Ptolemaic system (Hannam, 273). This situation did not improve until Johannes Kepler, who was working with measurements made by Tycho Brahe which were much more precise and complete than those previously available, realised that planets move in ellipses and not in circles as Copernicus supposed. Kepler published his Rudolphine Tables in 1627, based on Tycho’s measurements as well as his own, which at last gave a way of calculating the positions of the planets which could provide strong evidence for the Copernican theory. These more precise measurements allowed astronomers both to show the inadequacy of the old theory, and also to demonstrate the reliability of the predictions of the new theory (Hannam, 290-292). Galileo could have used the evidence from Kepler but, apparently, he did not (Hannam, 323). A case of the not invented here syndrome perhaps!

Most people today know that Galileo was put on trial by the Vatican authorities for insisting that the earth moved as set out in his 1632 book The Dialogue Concerning the Two Chief World Systems: The Ptolemaic and the Copernican. After the trial, he was placed under house arrest for the remainder of his life, and his book was placed on the list of books prohibited by the catholic church. Clearly this should not have happened. Putting people on trial and prohibiting books is no way to settle scientific disputes. Whilst we can rightly judge the treatment that Galileo and his book received, we shouldn’t judge people’s reluctance to accept the Copernican theory too hastily. We look back on these events with hindsight. We know that Galileo was right about the moving earth, but you can’t blame the people of the time for being doubtful. Some were sceptical of the idea of a moving earth for religious reasons as we know. Others were sceptical because it ‘just didn’t seem very likely’. I mean, the earth is moving? What a preposterous idea! Others resisted the new theory because, as we shall see, scientists do not give up established theories easily (Lennox, 24).

There was another problem in connection with the lack of precision of the available measurements, one which was not resolved in Galileo’s time. If the earth moves, then you would expect to measure stellar parallax: an apparent annual motion of the stars; and you do, but the effect is small and measurements precise enough to detect it were not available until much later. When you are travelling in a car, objects close to you appear to move past you more quickly than distant ones. The road signs rush past, the hills in the distance go past slowly, and very distant objects such as the moon don’t appear to move past at all. They just appear to follow you around! This effect is called parallax. Using parallax, school trigonometry will tell you how distant the objects you can see are. The idea also works on the stars provided you can make precise enough measurements since, like the car, the earth is moving. Stellar parallax due to the movement of the earth was finally observed in 1838 by the German scientist Friedrich Bessel (Carroll and Ostlie, 57-59).

The lack of evidence for stellar parallax in the time of Galileo, and for many years afterwards, was a serious objection to the idea of the motion of the earth. This problem was explained away by saying that the stars were too far away to measure the parallax (Hannam, 273; Brooke 85, 91). Like the motion of the moon when it seems to be following you around when you travel by car, the motion of the stars was too small to see. With the benefit of hindsight, we now know that this explanation was correct, but at the time, people were being asked to believe that the effects of the motion of the earth, such as stellar parallax were there without evidence; or rather they were asked to believe that the evidence would eventually turn up. And yet this was not an unreasonable thing to ask. The sun centred model was a more appealing explanation than the traditional one since it was simpler and less contrived. By contrived I mean arranged or created in a way that seems unrealistic or artificial; something that looks like a fix up. It was rational to believe the more appealing idea even when there were serious gaps in the evidence.

Unless you want to get into epicycles and deferents and so on (I don’t recommend it), Heath Robinson will do fine as description of the old earth centred model. Have a look at a Heath Robinson cartoon, if you haven’t before, and you will see what I mean. The contrivance got worse and worse as astronomers tried to fit the model to the new measurements by adding in more and more circles within circles. Copernicus and Kepler replaced the many circles, eventually, with one ellipse. Simplicity replaced contrivance with or without parallax.

We can contrast this story with the story of Newton’s Laws of Motion. Before I became a physics teacher, I imagined that Newton’s Laws were simple. Of course they are simple, and there is no sign of contrivance in them; but in watching students try to understand them, I gained a new admiration for them, and realised that their simplicity is a mark of their genius. It is their simplicity which gives them their appeal and their explanatory power. We can compare this with the simplicity of Copernicus’s idea of the earth going around the sun. Lots of people tried to work out what the principles of motion were, including Galileo. There are even ‘Galileo’s Laws of Motion’ which are now no more than a historical curiosity. But only Newton really got it. Once Newton had seen it, he made it simple for others to see.

For more than two centuries Newton’s Mechanics reigned supreme; it was scientific truth at its most impressive. But then a new equally impressive theory, electromagnetic theory, came along and it was realised that the theories could not both be true (Mackintosh et al, 30). Then more precise measurements, such as in the Hafele Keating experiment, showed that Newton’s mechanics has it limits, and Isaac had to make way for Albert. In our first example the evidence that eventually turned up confirmed the theory as expected. In the second example the opposite happened, as was not expected at all!

This does not mean that Newton’s theory is wrong. Newton’s mechanics has not been displaced but has been incorporated into the new more advanced theories (Misner et al, 412-413). Newton’s mechanics is just as impressive and powerful as before, but we now see that that it is incomplete.

As these examples show, all scientific knowledge is provisional. It is always possible for a new more precise measurement to be made or other evidence to emerge which shows that a universally accepted theory is in fact incomplete or false. But which scientific theories will be proven incomplete or just plain wrong? We know that some of them will be, but which ones? Once again, we have no way of knowing. We must believe – at least for now.

If human reason in general, and scientific knowledge in particular is fallible, if it is limited and provisional, if it makes unprovable assumptions, then why believe in it?

Because to ask for any knowledge to be infallible, unlimited, complete, and based only on things which are self-evidently true is to set an impossibly high bar. It would be, one would have to say, yes, unreasonable. It is also unnecessary.

Second belief: There is an underlying rational, reliable, intelligible order to the universe (Poole, 8)

… or to put it another way we expect the universe to make sense – we wouldn’t bother doing science if we didn’t.

• Order: The world can seem random, chaotic and capricious but underlying it all, there is order.
• Rational: We expect the universe to make sense.
• Intelligible: We expect to be able to make sense of it.
• Reliable: We expect the underlying rational order to be ‘the same yesterday, today and for ever’ and for that matter everywhere.

There is an extended version of this belief which many would prefer, including myself: there is a rational, reliable, intelligible, elegant order to the universe.

• Elegant: the underlying order has a dignified grace in appearance, movement, or behaviour.

That’s a little more subjective but I’d stand by it.

In an article in the New York Times entitled ‘Taking Science on Faith’, physicist and science writer Paul Davies says this:

All science proceeds on the assumption that nature is ordered in a rational and intelligible way. … When physicists probe to a deeper level of subatomic structure, or astronomers extend the reach of their instruments, they expect to encounter additional elegant mathematical order. And, so far, this faith has been justified.

The most refined expression of the rational intelligibility of the cosmos is found in the laws of physics, the fundamental rules on which nature runs … When I was a student, the laws of physics were regarded as completely off limits. The job of the scientist, we were told, is to discover the laws and apply them, not inquire into their provenance … Over the years I have often asked my physicist colleagues why the laws of physics are what they are. The answers vary from ‘that’s not a scientific question’ to ‘nobody knows’. The favourite reply is, ‘There is no reason they are what they are — they just are’ (Davies, ‘Taking Science on Faith’).

Does this mean that science is founded on faith? Yes: a justified faith! The success of science in explaining so much in a coherent, logical way is justification enough for the faith we placed in it.  We could not work out by pure logic that such a rational, reliable, intelligible order should exist. Neither could we work out what that order should be; but the scientific method can reveal it to us and the success of science can justify our belief in it.

From a very different branch of science, professor of medicine David Horrobin writes in a similar vein. He says that no scientist he knows ever thinks or worries about these things since they don’t affect the actual practice of science in any significant way; but they should be examined because science cannot be any more reliable that the assumptions which underpin it (Horrobin, 13).

This rational order includes, but is not limited to, what Eugene Wigner called the unreasonable effectiveness of mathematics. Wigner illustrated what he meant by using the example of Newton’s Law of Gravitation. This law originally concerned objects in free fall on the earth, an apple falling a from tree providing the original inspiration; and yet the same mathematical law was able to describe the motions of the planets to a precision which goes beyond any reasonable expectation (Wigner, ‘The Unreasonable Effectiveness of Mathematics in the Natural Sciences’). From the earth to the heavens in just one equation. Truly as Galileo pointed out: ‘The laws of nature are written in the language of mathematics’, the language of reason.

The success of science in making things and solving problems is even more remarkable. We live in an age of completely unprecedented material well-being. For the vast majority of people, both men and women, for the vast majority of history, life consisted of hard labour, dirt, danger and very little choice about anything. That doesn’t mean that life was unhappy or unfulfilling necessarily, but it was unrelentingly tough.

And yet now, few of us who live in the developed world need to worry about the basic necessities of life in the way that our forebears did up until, historically speaking, very recently. We can, most of us, expect to survive childhood and live to a good age in reasonable health; things our ancestors were only too aware that they could not take for granted. We have opportunities for travel, education, leisure, and freedoms which they could hardly even imagine.

In the past, someone like Henry the Eighth may have ruled a kingdom, owned multiple palaces, and had servants fawning over him, and labouring all day and night to satisfy his every whim; but he suffered terribly from painful medical ailments which would today be cleared up by a short course of antibiotics. We, most of us, truly live better than kings. This has been made possible by science. We should count our blessings every day. Faith in science: a faith justified indeed.

To finish this chapter, a return to the example of the Copernican theory. Naturally, we expect theories that are true to have the three c’s: comprehensiveness, consistency and coherence.

• comprehensive: taking into account all known relevant data
• consistent: free from internal contradiction
• coherent: holding together making overall sense (Poole, 48)

This doesn’t just apply to theories in science, but to any attempt to find a correct explanation for something, for example in history or in detective work. As we have noted, reality is messy and complicated, and no theory is going to fulfil these requirements perfectly; but if a theory seriously short of the three c’s, then we can probably eliminate it from our enquiries.

However, that is by no means the end of the story. The Copernican theory was preferred by its supporters to the Ptolemaic model partly for reasons which are not strictly to do with evidence or logic. This happens a lot in science. We noted earlier that in everyday life, we learn to rely on a combination of things to live successfully: instinct, experience, emotions, hunches, our senses, our values, our upbringing, our judgement, our intuition and, yes of course, our beliefs. Something not unlike this applies in science. There are various principles involved. You might call them empirical rules or rules of thumb, but they are more than that. They are partly to do with our expectation and belief that the universe makes sense. In the context of a book about faith it is tempting to call them wisdom.

They do not involve rigorous deductive logic of the kind that would be required in a mathematical proof; nevertheless, in combination they can build a ‘balance of probability’ case for pursuing a scientific idea; and they often come into play when there are gaps in the evidence. They rarely let you down. This is my version of the list.

1. Simplicity. The Copernican theory was simpler than the old idea. We expect the simplest explanation to be the correct one. This principle is often referred to as the principle of parsimony or Ockham’s razor named after William of Ockham, the 14th-century English philosopher and theologian. Some things require a complex explanation with multiple causes. For example, what if we asked the question, ‘why do some people commit crime?’ That is a controversial question and different people will come up with different answers. People can sometimes get quite passionate about this issue! Nevertheless, they will all agree that the causes of crime are complex and many. But as another famous mediaeval theologian Thomas Aquinas put it, ‘If a thing can be done adequately by means of one, it is superfluous to do it by means of several; for we observe that nature does not employ two instruments if one suffices’. We will come back to St Thomas Aquinas in chapter four.

We should note that preferring simplicity is a pragmatic principle, not a logical requirement. For example, as we said earlier, Galileo did not use Kepler’s results, including that idea that the planets moved in ellipses not circles in his book and thus did not present the strongest case available at the time (Lennox, 9-10). I mischievously suggested that this was because it wasn’t his own idea. On the other hand, perhaps he just couldn’t bring himself to give up the idea that the planets move in circles; after all a circle is simpler than an ellipse. But as Einstein put it, ‘explanations should be as simple as possible, but no simpler’.

2. Minimal contrivance. The Copernican theory involved less contrivance than the old idea. We don’t expect the universe to be like a Heath Robinson contraption; we expect it to be elegant, parsimonious. This is similar to the first principle, but it’s worth stating separately.
3. Don’t give up; but know when you’re beaten. Scientists don’t usually abandon a theory when it encounters difficulties, or if newly discovered evidence appears to contradict it. They hold their nerve since they know from experience that the new evidence may well turn out to be wrong or misleading. If the problem doesn’t go away, they modify the theory to fit the new situation. If you keep on doing this though, you can end up theory which looks increasingly contrived (see principle 2). The modifications become ever more ad hoc and even desperate. By ad hoc, I mean reactive not proactive, not part of a carefully thought-out planned strategy, thought up on the spot, improvised, or as some people would say, winging it. This is what happened in the case of the Ptolemaic theory. The old theory didn’t go without a fight – but they never do. Tycho Brahe even came up with the idea that, whilst the earth does not move and the sun and the moon orbit the earth, the other planets orbit the sun (Hannam, 283). With the benefit of hindsight, we can see that for the idea of the stationary earth, this really was Custer’s last stand; but at the time, Brahe was by no means obviously wrong. Old theories which need to die are eventually let go, although sometimes this is only because one generation of scientists has retired and been replaced by the next.

The complication here is that persevering in spite of the evidence, adding new bits to theories or modifying them, is often the right thing to do; when Kepler modified Copernicus’ theory by changing circles into ellipses for example. When it was realised in the 19^th century that Newton’s Laws of Motion and the new Electromagnetic Theory contradicted each other, neither theory was abandoned. In contrast to the case of the stationary earth theory, the difficulty was resolved. A new theory, special relativity, came along which brought the two together. Newton’s mechanics was modified so that it fitted in with the new regime and all was well in the world of physics for a while. A major problem in physics today is finding a way of consistently combining two of the main theories of modern physics: quantum mechanics and general relativity; that is to say, finding a theory of quantum gravity. General relativity theory is an extension of special relativity theory which includes the force of gravity. In spite of many years of effort, this problem remains unresolved (Mackintosh et al, 30-32); but physicists won’t be giving up on either theory any time soon. Physicists believe that one day there will be a theory that combines quantum mechanics and general relativity; or at least that it is worth putting a huge effort into trying to find one. This is not believing without evidence, but it is believing.

4. The power of prediction. The Copernican theory made testable predictions, e.g. the precise motions of the planets and the existence of stellar parallax. The lack of measured parallax was a problem, but it was also an opportunity! Eventually the prediction of the existence of stellar parallax turned out to be true. Explaining something that has already happened is much less impressive than correctly predicting something. When you try to explain something that is already known, it is all too easy to end up with a ‘just so story’, that is an explanation which may sound plausible but which is actually wrong. These are named after Rudyard Kipling's 1902 book ‘Just So Stories’ which gives amusing fictional explanations for such things as ‘How the Leopard got his Spots’. A theory which is capable of prediction is much less likely to be ‘just so’.
5. A mechanism. The Copernican theory is explained by an underlying mechanism i.e. the force of gravity defined mathematically by Newton’s law of gravitation. This explanation came long after Galileo’s trial but before the measurement of stellar parallax. Kepler described how the planets moved but Newton explained why they move in that way. This was a mechanism which explained a wide variety of apparently unrelated things as well, including of course the falling of apples. When a mechanism explains different phenomena which appeared previously to be unconnected, this is a strong reason for believing that the mechanism is telling you something about the underlying order of the universe. This is another example of the importance of simplification. If many different things have the same underlying explanation, then you have one explanation instead of many.
6. Falsifiability. This is different to the other principles in that it doesn’t indicate whether an idea is true or not, but rather whether it is scientific or not. Stellar parallax is doing an awful lot of heavy lifting in this example but here it is again! It provided a way of proving the Copernican theory wrong. If Copernicus was right then stellar parallax must exist; so, if it were shown that there was no parallax the theory would be proven false. In other words, the theory was falsifiable. In the end, of course, parallax was measured and the theory vindicated. In order to be scientific, most people would say, an idea must be falsifiable.

What if somebody claimed that they had fairies living at the bottom of their garden? You might say, ‘I’ve been to the bottom of your garden and I didn’t see any fairies.’ ‘Ah!’ they might say in reply. ‘That’s because they are hiding, and they are so good at hiding, you will never find them.’ There is no way in these circumstances that you could prove that your friend does not have fairy residents on his property. The claim is not falsifiable and therefore it is not scientific. But perhaps that example is a little frivolous. A police investigation would provide a more down to earth example. A detective questioning a suspect might ask them where they were between 7pm and 10pm last Thursday night. The suspect might reply that he was in the pub, spoke to his friends Bob and Susan, had a conversation about the weather with the barman, and paid for a round of drinks with his credit card. This is a good answer because it is falsifiable. The detective can, if he wishes, interrogate Bob, Susan and the barman and check the credit card records to find out if the suspect’s story is untrue. On the other hand, if the suspect says he went for a walk but no one saw him this may well be true, but it is not a satisfactory answer from the point of view of the policeman, because it is not falsifiable. It raises suspicions! Another example of an unfalsifiable claim is the multiverse theory which will be important in this book since it is put forward by many as an alternative to believing in God. I will argue later that, given the current state of scientific knowledge, it is the only alternative to believing in God. The claim is that as well as the universe we see and can measure and observe, the one we live in, there are countless other universes which we cannot see or measure or observe. It is impossible to prove that these other universes do not exist. This claim is not falsifiable and even if it is dressed up in scientific clothing, it is not a scientific claim.

Fairies at the bottom of the garden? Other universes? Do they exist? Faced with an unfalsifiable claim we must make a judgement as to whether it is sensible to believe it or not. Science will not settle the question for us. Obviously, most people would judge that believing in fairies at the bottom of the garden is not sensible. On the other hand, many would judge that believing in the multiverse is sensible, and I would agree that it is. But why exactly? We will pick this up again in chapter five.

These six principles will be useful later in the book in more ways than one. Watch out for them!

We noted at the beginning that, even to get started in science, you need to temper your scepticism to some degree, make some unprovable assumptions, and accept some pragmatic compromises.

We can now add that science involves using principles which aren’t strictly to do with deductive logic, or which sometimes don’t resemble deductive logic at all.  Sometimes, you just have to make a judgement about things. Science involves, sometimes, persevering with a theory in spite of a lack of evidence, or even in the teeth of the evidence. Science involves accepting that all scientific truths are provisional; but also believing that science as it is today is a step towards some greater truth yet to be discovered. Science depends on measurements but all measurements are inexact – and there is nothing we can do about it. In the scientific journey there will always be uncertainties, guesswork, blind alleyways, moments of inspiration, moments of pig-headedness, rivalries, egos, funding issues, and changes of mind a plenty. It is clear that science isn’t a simple matter of self-evident truths, observations, experiments and logic leading to scientific certainties. Even science, that most rational of activities, sometimes involves believing things. Nevertheless, we don’t say: the nature of scientific truth is a complex matter and doesn’t lead to simple certainties, therefore we might as well believe what we like; that would be ridiculous. Sometimes believing is just wishful thinking or bad thinking; on the other hand, sometimes it’s perfectly rational. In fact, sometimes, in order to be rational, it’s necessary to believe.

I will add another principle to my list, a Christian one this time. St Anslem was a philosopher and theologian who was Archbishop of Canterbury from 1093 to 1109. As he put it: ‘I do not seek to understand in order that I may believe, but rather, I believe in order that I may understand’. We do not need blind faith, or believing without evidence, but fides quaerens intellectum, the faith that seeks understanding. Science involves a faith seeking understanding, even if only when you are a student of science. When learning about Newton’s laws of motion, in my experience, students do not say: ‘I’m afraid, sir, you’re going to have to prove those before we accept them’. This is in spite of the fact that lots of students, around one third in my experience, have difficulty in believing them. ‘But sir, how can an object move without a force acting on it?’ When students had a problem believing that, I reassured them that they are in good company, Aristotle’s not the least, who was one of the scientific heroes whose picture was on my classroom wall. You have faith in Sir Isaac and your teacher and accept Newton’s laws first; the understanding and the proof come later. This is not believing without evidence; this is faith seeking understanding.

Faith in science is not a leap into the dark but a leap into the light. Might the same be true of faith in God?

Christianity is a faith but it is clearly not a science. The question here though is Christianity is a rational faith? The rest of this book sets out to show that Christianity is believing with evidence, as far as the evidence can take us; and beyond that it is a fides quaerens intellectum, a faith that seeks understanding.

I hope that chapter one has given you enough faith to persevere and read to the end of the book!

Summary

Science is the most reliable form of knowledge that we possess. It is based on evidence. It relies on observation, experiment, and reasoning. But like all human activities, it involves believing things, and often uses methods which are more pragmatic than logical. What are the beliefs that underpin science? How does it deal with complexities and uncertainties? What are its limitations? The answers to these questions provide us with useful background ideas which we refer to throughout the rest of the book.

Some claim that the Christian faith, in contrast with science, is ‘blind trust, in the absence of evidence, even in the teeth of evidence’; but the evidence shows otherwise.

Christianity is a faith, not a science, but it is not believing without evidence. Faith in God is not a leap in the dark, but a leap into the light.

Works Cited

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Francis Collins The Language of God: A Scientist Presents Evidence for Belief. Free Press, 2006.

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