originally published in Dutch in Geleerd en Gelovig, edited by Cees Dekker (Ten Have, 2008).
My field of research is quantum physics. Quantum physicists study the building blocks of matter, hoping to understand more of the properties of materials. The elementary building blocks are the protons and neutrons in an atomic nucleus and the electrons that move around it. My own specialism is the electron. It is the smallest of the building blocks, but not one you would easily overlook. The whole electronic industry (where I learned my profession, at the Philips Research Laboratory in Eindhoven) revolves around the electron.
The electron is full of wonders:
As you can see, the quantum world is a wonderful world, with very different properties and laws than the world that we can see with the naked eye. Physicists have developed a certain intuition for it, by comparing the electron with a wave. More precisely, the wave-particle duality states that the electron behaves like a wave, until you try to observe it – when it turns out to be a particle. In this way, I am able to imagine some of the strange properties of the electron. (For example, because a wave spreads in all directions, it is imaginable that the electron can be at two places at once.) Other properties (such as the entanglement of two electrons) remain unimaginable, my intuition fails me. Indeed, intuition (our ‘sixth sense’) is built up and supported by sensory perception and is handicapped in a world that we can only investigate with the help of instruments.
- It can be at two places at the same time and there is a law that forbids you to specify the position of a motionless electron.
- The electron diameter is zero, and yet it cannot pass through a narrow opening.
- Although it is infinitely small, the electron still has a mass and is also capable of spinning around its axis.
- An impenetrable barrier for electrons does not exist: there remains always a chance that an electron will tunnel through the barrier.
- Electrons can be entangled by an unobservable string and this entanglement might one day be used to build the fastest computer in the universe.
Although I can only trust my intuition to a limited extent, and although I have only a vague image of the electron, I can still predict the properties of electrical circuits with great certainty. For that purpose I rely on mathematics. I can calculate the probability that an electron is at a certain position, as well as the probability that it will tunnel through a barrier, by taking the absolute value squared of a complex function, the wave function, which in turn I calculate by solving a differential equation (the Schrödinger equation). The same equation also tells me how wide an opening should be, to allow the electron to pass through it. I find the direction in which an electron spins along its axis by calculating the eigenvalues of a Pauli matrix, and another matrix tells me whether or not two electrons are entangled.
If you find these words incomprehensible, rest assured that they are a fully logical and understandable language for the physicist. By relying on the language of mathematics, I do not have to imagine the electron and I do not have to rely on my limited intuition for a particle that is also a wave. I rely on formulas because the answers that I calculate can be tested against reality: my colleagues in Delft actually measure in their lab the electronic circuits that I draw on my black board in Leiden; if the calculation agrees with the measurement, then my confidence in the formulas grows. I then dare to trust them even when there is no measurement (yet). I have become convinced that quantum physics is the truth.
In the same period of my life that I developed my intuition for quantum physics and gave it a solid foundation through mathematics, as a student at Leiden University, I also received and took the chance to develop a ‘sixth sense’ for Christian spirituality. I had earlier acquired some knowledge of Christianity, in particular the Catholic faith, during my high school education. The weekly religion classes were an intellectual affair, my heart was not really involved. A sensory experience of God was strange for me, until that weekend in the Fall of 1979 when I discovered, while I was visiting a monastery, how God reveals himself (more on this later).
Since that time I live from the conviction that God exists, that He knows me and that He loves me. A physicist who believes in a personal and loving God is somewhat of a rarity. A colleague once supposed that such a person is likely to have a split personality. Let me try to convince you of the contrary.
God is full of wonders:
As you can see, the ways and thoughts of God amaze us, they are so different from the ways and thoughts of humans. I have attempted to develop a certain intuition for it. Theologians tell me that this is not a futile attempt, because the human mind is capax Dei (literally, ‘capable of God’) – so it has the capacity to know what is of God. What helped me is to ask myself: “How could it have been otherwise?”
- He is the Creator who does not intervene in his creation.
- Although He is loving and almighty, He does not stop the suffering.
- God did not prevent his only Son to be brought to death.
- He promised his followers eternal life, and yet they too must die.
- God wishes to be known, but experiences of God are not reproducible.
How might God intervene in his creation, without diminishing its order?
I like to compare the creation with this familiar event called Domino Day. You may know it from television, an enormously large hall is filled completely with millions of domino stones, the first stone is toppled and then in a chain reaction one domino stone falls after the other. It is an impressive spectacle, with all kinds of twists and turns. There is one golden rule: it is forbidden to intervene after the first domino stone is toppled. If the chain of falling stones stops, then the creation has failed. This demands a special providence of the designers, everything has to be in just the right order, but that is precisely what makes the event so impressive. Could the divine providence be less impressive?
I have been asked more than once if I have encountered God in my search for the fundamental laws of nature. My negative answer disappoints some, but for me it is just the opposite: I would be disappointed if I would encounter a sign that would say: “Go no further”. Disappointed, if the laws of nature would not be complete, because of phenomena that could not be understood without recourse to divine intervention. In the past there were many of these phenomena (lightning and thunder, solar eclipses, the origin of species, human consciousness), today there are far fewer, perhaps not one will remain. This triumph of science is for me a triumph of the Creator. Nature presents itself to us as a fully ordered construction, everything fits, everything is understandable.
An understandable nature is not self-evident. Imagine that the world would resemble one of those old-fashioned show boxes (what we call a “kijkdoos” in Dutch). A show box presents a fine landscape, but only if you look into the box through a small hole. You cannot be too curious, you cannot for example look into the show box from the top, because then you will spoil the illusion. A show box can be admired, but you may not be too inquisitive. People make show boxes (the virtual online world ‘Second Life’ is a recent variety). That nature is not a show box, is for me a proof of Gods existence.
At this point I subscribe to the first part of a well-known quote of Albert Einstein, that he believed in a God “who reveals himself in the orderly harmony of what exists”. (Einstein added to this that he does not believe in a God “who concerns himself with the fates and actions of human beings”, but I cannot reconcile this with my own experience of Gods love.)
How might God prevent suffering, without diminishing our freedom and responsibility?
I imagine what it would imply if a statistical analysis would show that religious people have a smaller probability to experience an airplane accident than nonreligious people. To believe in God would then be like taking travel insurance, it would no longer be a fully free decision. And what would remain of our responsibility if we could rely on God to intervene in natural disasters, famine, terrorism, climate change, and so on? God as a safety net would reduce us to children without responsibility.
It is precisely because God does not intervene in the creation, that He leaves my responsibility intact and respects my free choice to believe in Him or not. I need not fear disease or accident as punishment, should I decide to stop going to church. I also need not count on success in my work or happiness in my private life as reward, because I go to church. Sometimes I might wish it were otherwise, but the loss of freedom would be too high a price to pay.
I feel this is an essential development that I have been through, when I compare my faith as a child with my faith as an adult. As a child I believed that good things that happened to me were a reward and bad things a punishment. I now understand that this is superstition, not faith. A superstitious person thinks that nature reacts to feelings and thoughts. For example when you touch wood after an optimistic remark (“I have never broken anything while skiing”), out of fear that this remark might evoke the opposite. I would actually enjoy it if my faith in God would come with perks, but I know it is not like that – and it is better this way. I could not choose for God in full freedom if I knew that this choice would protect me from disease or accidents. I trust that God will be lovingly close, whatever disaster might happen to me, but he need not divert the disaster to ‘earn’ my love. I trust that his loving closeness will be all I need to persevere in a time of trial.
I write ‘I trust” instead of ‘I know’, because I have not experienced much disaster in my life. My trust in God has (not) yet really been tested. I sometimes ask myself why. Why am I healthy while my brother is not? I can give no other reason than chance. Chance exists, I am convinced of it – in any case it is not in contradiction with any law of nature. The order of creation, as it is written in the laws of nature, refers to the rules of the game but not to the outcome. It is for the same reason that the immutable laws of nature allow for a free human will. I think that God allows chance because without chance no free will would be possible.
The free will is the result of a thought process that cannot be predicted in advance. Shall I do this or that – I am free to choose. We do not (yet) know precisely how the human brain works, but even once we have fully accounted for all chemical reactions and electrical currents in the brain, then the outcome of a thought process will still remain unpredictable because of chance. Chemical reactions and electrical currents fluctuate, only the averages are determined. Because of these random fluctuations the free will can coexist with immutable laws of nature.
How might God have defeated death without entering into death himself?
The suffering, death, and resurrection of the Son of God represent either a foolish story or a brilliant solution to an apparently unsolvable problem. The first possibility speaks for itself, the second possibility demands some further explanation. You might think that a victory on death should be easy for an almighty God, but the problem is that God himself is immortal and thus has no grip on death. Solving problems is my day job, but I would never have found such a brilliantly simple and effective solution: by becoming human without discarding his divinity, God could engage in battle with death.
I spoke before about the duality of the electron, which is both wave and particle. Even if this seems contradictory to you, you might accept it as true upon my authority as a physicist. Theologians speak of the duality of Jesus Christ, who was both God and human. I lack a talent for theological reasoning, but I surrender with confidence to an idea that has withstood two thousand years of critical questioning. To have confidence in the authority of reliable scholars comes natural to me, I do it each day I move beyond my own field of specialization. I feel no need to develop my own theology – the theology of the Catholic church suffices for me.
How might we live eternally without dying first?
The finiteness of life is a physical law that seems unavoidable. Every form of order succumbs to disorder. We call this a Law with a capital because all matter must obey it: even our own sun will once ‘die’ and extinguish itself. The eternal life that God has promised us through his Son can therefore not be a physical reality. The information that is lost at the death of an individual cannot be retrieved by physical means. Perhaps not everything is lost, part of the thoughts of a person can live on as a more or less tangible memory. But eventually also those memories will disappear. I have once calculated how many bits of information are needed to reconstruct 50,000 years of humanity: the number is a 1 followed by more than 40 zeros. We can be very sure that this information is not stored somewhere here on earth, so that even a very advanced civilization in the distant future cannot possibly bring the dead back to life.
And yet I live in the conviction that I will live on after my death in the presence of my Creator. I have no idea how God will succeed in preserving the information that makes me into a unique being, but I have decided to trust that it is possible. What strengthens me in my confidence is the experience that our human imagination is quite limited. In my profession I use mathematics to go beyond my intuition, but mathematics works only within the bounds of physics. I accept a reality outside of physics, which is not bound by the Law of the loss of information. I am prepared to be surprised by God.
What little we know of the eternal life is ultimately the only thing we need to know: that we shall see God “face to face”. It is attractive to look forward to a reunion with loved ones who have passed away, to catch up and pick up where we left off. Who knows, it might happen, but I am not counting too much on it. The old ties of friendship will probably not matter much when one has entered into Gods infinite love.
How might an experience of God be reproducible?
Most physical phenomena can be reproduced on command. A phenomenon may be very difficult to observe, but under identical circumstances the observation should be reproducible. The Internet is full of bizarre experiences that no scientist takes seriously, not because they are bizarre, but because they are not reproducible. Telepathy (mind reading) is an example of a non reproducible experience. Telepathy is unphysical because it cannot be reproduced on command.
An experience of God is unphysical, how could it be otherwise. As a physicist, therefore, I can’t do much with an experience of God and yet I could not live without it. If I try to capture what I have experienced of God in physical terms, then the notion of a resonance comes closest. I play the flute and sometimes an object (a vase or a glass) in my room starts to vibrate at a certain tone that I play. Apparently that object can vibrate at the same frequency as a tone from my flute; we say that the tone resonates. The word resonance originally meant ‘echo’, but the significance of the word in physics is different: for an echo the original tone is reflected back, but for a resonance the tone is newly formed. Unlike an echo, a resonance is very selective: if the frequency of the tone does not match precisely, nothing will happen, but if it matches then the result can be overwhelming. I have not witnessed it myself, but it is said that a crystal glass can be shattered by a resonance when an opera singer hits the right note.
I compare my personal experience of God with a resonance, because it feels as something that comes from outside of me and yet it matches me precisely. I remember the first time, when as a 19-year old I spent my first night in a monastery. I remember how I described to a school friend that experience of a personal God, and the vibration it provoked in my deepest being, and I remember her reaction: “The human mind can play strange games with us”. But it did not feel at all like that, it really felt as something that came from outside of me, not as an emotion that I had produced myself. I can recognize those self-produced emotions, they only make a brief impression. This first experience of God has made a lasting impression on me. I had the feeling that one of my senses was addressed, which is why I refer to that experience of God as sensory and intuitive (intuition is after all called the ‘sixth sense’). It was an immediate knowing, which is also a characteristic of intuition, very different from the gradual knowing that results from intellectual analysis.
I wish that this would happen more often, but it is not so. I can remember another occasion shortly before my father died, and a few other less clear resonances. It seems I will have to do with those. It is enough.
I end where I started, with the electron that is the subject of my daily studies and that yet has remained so full of wonders. A few years ago I thought of a way to destroy the electron at one place and to then let it continue its existence at another place, without having to exchange any precise information. The details do not matter much here – you can read the whole story on the internet if you're curious. Before I knew how to do it, it seemed impossible to me: the properties of the electron have remained unknown, how could they ever reappear somewhere else? But when the solution occurred to me, it seemed to simple that I did not understand how I could have been blind for it. It was as if I had passed through a ‘cloud of unknowing’ and now finally could see clearly.
I trust that once I will look back like this on the questions of faith that I’m now struggling with. I have recognized the cloud of unknowing which separates me from God, and the resonance that can evoke an experience of God in my heart, in the encouraging words of an anonymous hermit from the 14th century: “For at first you will feel nothing but darkness, and as it were a cloud of unknowing; you do not know what it means and yet you discover in your deepest depth a desire for God. This darkness and this cloud remain, whatever you try, between you and God, and they are the cause that you may neither see Him intellectually by the light of understanding, nor feel Him emotionally by the sweetness of love. And therefore, be prepared to wait in this darkness as long as you may, evermore crying out to Him that you love. For if ever you shall feel Him or see Him in this life, it will be in this cloud, in this darkness.”