Why we can’t prove Christianity is true (and why that isn’t a problem)

I’m a scientist. Specifically, I study how the molecules and cells in human brains may contribute to disease. I spend a lot of my waking time thinking about disease, cellular breakdown and, ultimately, death. I also happen to believe that about 2,000 years ago a man –whose DNA could be sequenced, whose brain functioned with synapses between neurons and whose blood pumped through his veins for over 3 decades – died. I also believe that after 3 days this man came back to life.

To be clear, I do not believe that he was close to a state of death which was misdiagnosed, nor do I believe he was resuscitated. I believe he was dead one moment, and alive the other. 

You might want to have proof of why I believe this to be true. Simply put, I cannot give you any proof. And yet, I am utterly rationally convinced that this is possible, and that this does not undermine or neglect my scientific mind.

How is this possible?

To answer this, let’s start by asking three questions: (i) What is proof? (ii) What has science ever proven? (iii) What is required for a hypothesis to be reasonable?

What is proof?

The speaker walked onto the stage for the last plenary session of the conference. Eccentrically dressed in shorts and a long-sleeved collared shirt and jumper, wearing socks and birkenstocks. The evidence was plain that he was either destitute and slightly mad, or a genius. He eloquently told the audience the history of Alzheimer’s disease research in detail. After explaining the amyloid hypothesis, he presented a diagram outlining a theory for the Alzheimer's disease cellular process. The evidence made sense, and his rationale was completely reasonable. “We spent over 10 years working and publishing on this” he paused. “We were completely wrong.” Although the previous 10 minutes were convincing me of the “genius” hypothesis, this statement made me reconsider my stance.

Who was this man? A terrible researcher, wasting tax-payers money and staff’s time on a hypothesis which was incorrect? Did he willingly delay research into neurodegeneration by focusing on the wrong thing? 

Often, people take one of two perspectives of scientists. Either that scientists have proven any and all useful information and knowledge - making scientists demi-gods, bestowed with all kinds of accolades, titles and awards - or that scientists are really deceiving the population in order to meet a social/political/economic agenda. Strangely, both of these perspectives raise scientists onto a pedestal that scientists and science itself are unworthy of. Both views treat scientists as those who bear truth, the first as benevolent truth-bearers, the latter as willingly deceitful truth-bearers. Neither of these views is particularly helpful or scientific. I would argue that this is a surprisingly religious perspective of science and scientists. Part of the reason for this canonized view of science is inherited from the enlightenment, that reason and scientific endeavour are the path to truth and, if science is the only way we reach truth, then clearly one must prove everything to be true. 

Mathematics seems an excellent example of the importance of proof. All sciences rest on the firm foundations of mathematics, and this – sometimes thought of as the most pure form of science – consists mostly of mathematical proofs. This supports the hypothesis of the enlightenment, that science is the path to truth. That is, until we reflect on the nature of mathematical proof. 

Mathematical proof is not about proving or demonstrating that something is always true, but actually about knowing what are appropriate conditions to begin a mathematical proof. Mathematical proof is a relative rather than an absolute. Evidence of this is that by beginning with the incorrect conditions and assumptions, almost anything can be proved mathematically. One maths teacher drove this concept home to me when he, through assumptions which seemed entirely plausible and reasonable, proved to me that 1+1=1. A mathematical proof is a demonstration that under those proposed circumstances with those given assumptions, this demonstration should hold through.

This same principle applies to other areas of science, and is why, according to a study conducted by the scientific journal Nature, depending on the field, as few as 24% of scientific studies can be reproduced [1]. In studies that cannot be reproduced it is likely that the conclusion links to context or conditions which were not accounted for. A proof doesn’t mean that an aspect of the natural world necessarily always occurs in the same way, it simply demonstrates that in these circumstances, with this hypothesis, a particular phenomenon can be demonstrated, predicted and repeated – the trick is to know the circumstances.

Can anything be proven?

In late summer in 1687 Isaac Newton described gravity. He observed this due to an apple falling from an apple tree in Trinity College, Cambridge. In spite of the circumstances in which he observed this, we can now be certain that this was not a phenomenon unique to late summer, to the 17th century, to that particular genetic strand of that apple tree, or to that patch of ground in Cambridge which is now crowded with tourists. It has been observed in many parts of the world, and explains many other phenomena in the universe. And yet, Isaac Newton would struggle to prove gravity is always true. He could try to drop apples all day on Magnetic Hill (India), Reverse waterfall (Faroe Islands) and Mount Aragats (Armenia), and he would not be able to prove it. In these locations, water and cars are known to roll uphill, regardless of the season, type of apple in question or the century. Moreover, if we were to leave planet earth, he might also have difficulties with black holes, as the core of a black hole is called a ‘singularity’, where conventional laws of physics are predicted to not apply. 

What is reported in popular news outlets as ‘proofs’ in science, in reality, amount to evidence. Every mathematical model, experimental model system and theoretical prediction must be considered within a body of evidence. An important aspect of this body of evidence is the environment, the constraints and the conditions which together facilitate the occurrence or the accuracy of that phenomenon.  Even for phenomena that are true in most circumstances – such as gravity - it is not absolutely true and cannot be truly proven. There often is an exception.

Can something be true if it cannot be proven?

This amounts to a perhaps troubling reality: that we cannot prove anything is always true. You will never be able to prove your love is always true. Similarly, a lawyer will never be able to prove that a perpetrator of a serious crime is true. But this is especially troubling for those who expect that all reliable facts come from scientific discovery.

These statements may seem disturbing, and yet they are completely consistent with how we make decisions and go through life in practice. For example, have you ever disassembled a chair, measured the amount of force each screw and part can sustain, and proven that this chair can certainly hold your weight before taking a seat? Or have you normally been content that, upon walking into a busy café, seeing a free chair assumed that if it is here, it has most likely been used by other people – possibly heavier people than you – and that it can probably handle your weight? On the other hand, if you enter an abandoned house and see a chair completely covered in dust and with several deep cracks, you may be hesitant of dropping your entire weight on it. In both cases, you have subconsciously gathered evidence of whether to trust the integrity of a chair, and have made a decision of whether to sit or not to sit based on the evidence before you.

This means that even though you may never be able to prove your love, you can provide abundant evidence of your love – and the longer you remain in a relationship, the more opportunities to do so you will have. The marriage vows acknowledge that the key to love is that it remains true through all circumstances – sickness or health, wealth or poverty – amounting to a lifetime of evidence of love. The evidence will – hopefully – grow increasingly more convincing, as said love withstands a greater range of circumstances and challenges.

Can faith be based on evidence?

“Do you have faith in your wife, Professor Dawkins?”, asked the mathematician Professor John Lennox in a debate held at the University of Oxford in 2017. “Yes, I do.” “And do you have any evidence of this?”. A flustered Richard Dawkins fumbled for words, while Dr. Lennox cheekily smiled and the audience in the “The God Delusion” debate laughed. Richard Dawkins, who had fervently stated that all faith is blind and not based on evidence, struggled to respond. On this occasion, Dr. Lennox was challenging the belief that all faith is, by definition, blind. Appropriately for the case he was making, Prof Lennox challenged this belief professed by Prof Dawkins by providing evidence.

For many atheists and agnostics, the thought of believing in a worldview that cannot be proven is perceived as an intellectual weakness. However, this assumption is in direct conflict with the way that humans behave, and with the fact that no worldview can be proven. The only thing we have left to work with is evidence.

Ultimately, this means I cannot prove that Christianity is true. But we cannot prove anything else is true either. What I do believe is that there is a huge amount of evidence supporting Christianity, in fact I believe there is more compelling evidence that Christianity is true than any other worldview to date. Not only does Christianity provide us with a framework that is scientifically robust, it can address non-scientific questions as well: Is morality real? Is there value in human rights? What is beauty? Other scientists we build our science on also agreed with the value of the Christian worldview - Newton, Pasteur, Pascal, Galileo, Mendel, Keppler (just to name a few). 

Perhaps, there is one particular worldview that you have held for many years - perhaps due to tradition, peer pressure, personal experience or something else entirely. Revisiting the evidence is always scientifically sound. Have you ever really looked at the evidence of Christianity? Did Jesus exist? Who was Jesus? I said at the beginning that I believe he was real and that he resurrected from the dead. Have you ever looked at the evidence for these claims?

Do you remember the scientist I mentioned earlier in this talk? The eccentric in socks and Brikenstoks talking about how he spent 10 years on a hypothesis that was completely wrong? The way he stopped and reconsidered the evidence wasn’t embarrassing, and definitely doesn’t make him a bad scientist. This is Prof Sir John Hardy - a brilliant and delightfully eccentric scientist who has played no small part in the discovery of several genes associated with Alzheimer’s disease. He has been awarded almost every prize and accolade short of a Nobel prize, and him being able to reconsider that hypothesis was instrumental for Alzheimer’s research, contributing to the development of the first disease modifying therapies for Alzheimer’s disease. Even after 10 years of research and millions of pounds of funding it wasn’t too late for him to reconsider the evidence. It is also not too late for you to examine the evidence for Christianity. It might even change the most important hypothesis you ever had.

[1] https://www.nature.com/articles/533452a