Wonders of the Living World: from Randomness to Life
I’m glad Rhoda Hawkins is my friend for many reasons, but one specific point to be grateful for is that she is willing to patiently teach others about her work in theoretical physics. As a writer on science and religion I often collaborate with working scientists. So when I wanted to communicate something about the role of statistical mechanics in living organisms I knew I needed to get in touch with someone who was keen to communicate the full beauty of her subject.
My own studies were in genetics. I was drawn in by the creativity involved in designing experiments to figure out aspects of how DNA works. While biologists tend to work with aspects of quite complex systems, most physicists try to break things down further so they can study single forces, or small sets of parameters. Rhoda is a theoretical physicist who produces mathematical models of biological systems. These models are simplified by necessity, so that they can help explain some aspects of biological processes.
The question that fascinates Rhoda is, ‘Why are things alive?’ As a physicist she looks at a cell moving (you can see videos on YouTube) and asks, ‘Why is that thing, which has the consistency of a blob of hair gel, able to move by itself?’ The understated way a physicist describes life is ‘out of equilibrium’. In other words, when supplied with the nutrients and other conditions it needs to stay alive, a cell can maintain its physical structure (resist decay), move around, and interact with its environment. I can easily take this sort of behaviour for granted, but with a mind full of the sorts of questions that a physicist usually asks about materials, Rhoda finds it utterly wonderful.
One of the most wonderful things about living organisms is that their bodies are, in a sense, powered by randomness. The order we see down a microscope: the cell wall, the nucleus with its DNA, skeleton fibres and so on, are the product of tiny molecules moving about in liquid water. This Brownian motion enables the molecules to bump into each other and interact. Some molecules or collections of molecules will just bounce off each other. Others will stick, or at least for a time. Still others will react with each other or be held together by active processes.
For example, a cell moves because its inner skeleton moves like caterpillar tracks. Each fibre of the skeleton moves in a particular direction because subunits drop off more frequently than they stick on at one end, and stick on more frequently at the other. The sticking on and dropping off movements are random, but the particular properties of the subunits produce an overall pattern.
A gambler cannot say which number they will roll next, but they do know they are likely to get a six at some point if they keep trying. In a similar way, a scientist would be unable to say for sure which molecule will stick to the skeleton fibre next, but they might be able to predict which way the cell will move.
Rhoda is a Christian, and when she manages to describe one of the cell’s intricate mechanisms with a mathematical equation, she feels that she is seeing the mind of God. For her, the beauty and complexity of the world, and the simplicity of its underlying physical laws and principles, are amazing. “This leads me to worship the creator who made these amazing things and processes in the universe.” She believes that God created the universe, on purpose, and that his work is good. It seems that, as part of the creative process, he uses randomness to produce order. For her, “It is possible for God to use random processes to make the world and yet still have purpose in that.”
What about on a human scale? Does God have a final purpose that makes sense of details in our lives that don’t seem to make sense to us at the time? For Rhoda, there are many answers to questions like this in the Bible but they are not always completely clear – understanding them will always be an ongoing process. She has had periods of doubting and exploring different answers, reading, and talking to people about their own views. Those times have always strengthened her faith in the long run.
Ruth Bancewicz