What Makes Clocks And Cats Different? - a hand-drawn clock on the left and a funny comic-like hand-drawn cat on the right. The word "Vs." in between.

Let us play a little game. What do clocks and cats have in common? For starters, both transform energy from an input source (batteries for clocks and food for cats) using a chemical process to do work. I would have said “useful work”, but that honor belongs exclusively to clocks.

Going from function to form, both clocks and cats share compositional chemical elements such as oxygen, nitrogen, carbon, etc. At a finer level, both are made of electrons, protons, neutrons, etc.

Even with so much similarity at the micro-level, we note that cats are living beings while clocks are not. Why is this?

What differentiates living beings from non-living things?

This is the question that I will be exploring in this essay.

Physics Vs. Biology

Physics and biology might both be branches of science, but they take fundamentally different approaches to the same question.

As far as biologists are concerned, life emerges from systems that perform self-sustaining functions such as ingestion, digestion, excretion, and most importantly, the self-replicating function of reproduction. We could call this the emergent approach.

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On the contrary, physicists believe the key to understanding the phenomenon we call life lies in reducing the complexity to explore unique properties and behavior of the underlying basic constituents. We could call this the reductionist approach.

Over the past couple of centuries, both approaches have evolved vastly and have taken us far in understanding life as a phenomenon. There are even hybrid sub-fields that combine these approaches.

Despite all of this, we are still far away from answering the fundamental question we started with: What differentiates living beings from non-living things? Why is this?

What We Know So Far

Genius physicist and Nobel laureate Erwin Schrödinger once shared something very interesting in one of his lectures. When a few atoms of the body or the brain fail to do their function, life continues without issues.

In other words, life is robust enough not to be dependent on small clusters of atoms. However, when large groups of atoms that make a body part fail to do their function, life runs into issues. What does this say about the nature of life?

Emergent Behaviour — An illustration showing a flock of birds dancing like a living creature through the sky. Besides this flock, the following text is highlighted: “Emergent Behaviour”.
Emergent Behaviour — Illustrative art created by the author

To me, it is quite clear that life emerges from large collections of atoms arranged in unique patterns. Look at any complex adaptive system, and you will notice that they behave remarkably similar to a single life form.

Furthermore, these systems seem to have a fractal nature to them as well, as we notice more and more similarities in the interactivity between atoms, molecules, and organisms when arranged in similar patterns.

This is definitely useful knowledge. But what can we do with this?

Where Do We Go from Here?

If you notice closely, our current knowledge about the phenomenon we call life combines various approaches including the emergent and the reductionist ones.

I think the key lies in continuing to attack the question we started with from various angles. Historically speaking, we have achieved breakthroughs often by coming up with unique views.

What Makes Clocks And Cats Different? — a hand-drawn clock on the left and a funny comic-like hand-drawn cat on the right. The word “Vs.” in between.
Clock vs. Cat — Illustrative art created by the author

An interesting property of such perspectives is that they also have an emergent nature to them. When you approach a topic one way or another, things appear mutually exclusive. But when you lay the approaches on top of each other in a specific pattern, a fresh view that is more than the sum of its parts emerges.

While it appears that we are nowhere close to answering what differentiates the living from the non-living, all we can do is to continue exploring and chipping away.

I will be exploring some more interesting approaches in a future essay. In case you aren’t aware, this is my fifth essay in this series. I recommend that you check out the prior essays to gain more context if you haven’t already.

In the meantime, I hope you enjoyed reading this one!

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Further reading that might interest you: 

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Reference and Credit: Brian Greene

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