What is Life? “I am not going to answer this question. In fact, I doubt if it will ever be possible to give a full answer, because we know what it feels like to be alive, just as we know what redness, or pain, or effort are. So we cannot describe them in terms of anything else. But it is not a foolish question to ask…”
JBS Haldane, What is Life? 1949
Gene-i-us at Work: What Is Life?
In the spirit of Mr Haldane, as well as a kind of natural conclusion to the Director’s previous two columns, today’s paltry words are on the question, ‘what is life?’
Like Mr Haldane, I don’t think we have a good definition of this thing called life. And I think it’s for three main reasons. Firstly, life is perhaps the one thing we all have in common, and let’s face it, it’s very difficult to get a group of people to all agree on something; especially if that group of people is made up of absolutely everyone. Secondly, life can only really be described in terms of…well…life, so we get into a kind of circle of definition. I don’t mind that particularly, after all the post modernists, as you know, would have us believe that all language is itself circular by definition (words are only defined by other words) but that’s for another column. Thirdly, and I reckon this is the best one; life is a mystery. To paraphrase the philosopher William James it is not something we can ever close our account on. It’s certainly something of a moving target at least. With your indulgence, let’s have a little look.
Science, that steadfast navigator of the unknown, offers us its frameworks. Life, we are told, is a system capable of metabolism, growth, reproduction, and adaptation. But does a list of symptoms truly explain the illness? Or, in the case of life, the miracle?
In his 2020 book What Is Life? Five Great Ideas in Biology, Nobel prize winning geneticist and cell biologist, Sir Paul Nurse offers us his exploration of the question. As suggested by the title, Sir Paul splits his response to ‘the big question of biology’ into five key areas. It would seem a felicitous place for us to start.
So first off, dear reader, we have the cell which by all accounts is the simplest entity that expresses characteristics of life: it can grow, divide, it can reproduce. And every living thing is either a single cell or made up of groups of cells acting together. My esteemed colleague, Mr Rennie, drew my attention to yeast after last week’s column. And Sir Paul does likewise in his book. Apparently yeast is very good as a model for other cells in all sorts of more complicated living things including me, and I’m guessing you, dear reader.
Somewhere between a thousand and fifteen hundred million years ago in the evolutionary chain of events, yeast and human beings diverged, but Sir Paul in his lab found a human gene that could completely substitute for the yeast gene that controls the reproduction of a cell from one to two. A human gene controlling the reproduction of a yeast cell just as well as it could control the reproduction of a human cell.
Crikey.
Which suggests that every living thing is therefore controlled by the same mechanism.
Blimey.
The second of the five great ideas is the Gene itself. My reader may well remember as I do, being taught about the monk Gregor Mendel and his peas. Mendel crossed peas with different characteristics and counted the different types of offspring that were produced from these pea plants. He noticed there were very clear ratios and realised that maybe what was responsible for inheritance could be described as a sort of unitary particle which could be passed down from one plant to another. This was then the first evidence that there was something which would now be called, a gene. Indeed Mendel’s work established the foundation for modern genetics, though its significance was only recognised years after his death. It’s often the way.
The gene now neatly segues into Sir Paul’s third great biological idea, namely our old friend natural selection. Charles Darwin, as you know, came up with the idea of evolution by natural selection. He took the notion that all living things have hereditary material and speculated that if this hereditary material had some differences that resulted in the living thing being different, and if it was advantageous in the environment in which it then found itself, it would eventually take over the whole population. Thus there can be better designed living things but no designer involved in the designing of those better designed living things.
The fourth of the great biological ideas involves another old friend; chemistry. Living things are made up of molecules and chemicals and there are many thousands of chemical reactions going on all the time in a cell. It’s chemistry which is responsible for the growth of the cell, the reproduction of that cell, as well as for its ability to capture energy and use energy.
So living material is chemistry, but it is also built on information, which is Sir Paul’s fifth great idea. Living stuff has to constantly manage information. For example, all the chemical reactions going on in the cell can only occur if there’s an information transmission to keep the whole thing coordinated. If we take DNA, we could understand the structure of DNA in terms of how one base is related to another base, but it only makes biological sense when seen to be a digital information storage device. So for Sir Paul, living matter is, and can only operate through, information and it also permeates every aspect of how living things work.
Sir Paul puts those five ideas together and derives the following principles:
Living things are bounded physical entities.
The bounded entity is the chemical and informational machine.
That informational chemical machine in a bounded entity has a hereditary system that determines how it works, a system which has variability, and therefore can evolve by natural selection.
Sir Paul takes these principles as being where ‘purpose’ comes into the life equation. For Sir Paul, a living thing’s purpose is to be better adapted in the life state it finds itself in. Hurrah, at last I can tell my mother I have found my purpose in life. She will be pleased.
Now, I think Sir Paul has done a lovely job there to emphasise the core principles underlying living matter. And therefore helped us to clarify perhaps, the difference between something that’s alive and something that is not alive. But does defining what constitutes living matter get us any closer to understanding what life actually is? I think not.
When Hamlet tells us that the question is to be or not to be… Shakespeare is pointing at something quite separate from whether it’s better to be an informational chemical machine in a bounded entity with a hereditary system possessed of variability, or not to be an informational chemical machine in a bounded entity with a hereditary system possessed of variability. Apart from anything else, it may have been even beyond the Bard’s considerable skill to get all that into blank verse.
There are perhaps three problematic areas in the ‘core principles’ approach to what life is which might be worth visiting. Firstly, and this is referred to by Haldane at the top of the article where he is really talking about the sui generis nature of life, whatever life is, it is uniquely its own thing. And therefore to attempt to reduce it to processes, albeit mysterious and wonderful in their own way, is a pretty barren exercise. Secondly, and Sir Paul himself brings this idea in, so don’t blame me, we have the idea of ‘purpose’. Haldane also refers to this difficulty that scientists have when it comes to describing the processes which originate and perpetuate life. He apparently once remarked; Teleology is like a mistress to a biologist: he cannot live without her but he’s unwilling to be seen with her in public. Teleology here refers to Aristotle’s concept of the telos, by which he meant, the purpose or final cause of something. I’m not sure what the mistress bit refers to. Nevertheless we have discussed in previous columns the idea of evolution having a telos so I shall not rehash here. But the idea leads to the third problematic area, which is what our friend Richard Dawkins I think has referred to as the ‘paradox of the organism’. Undoubtedly, I’ll get this wrong, but my understanding of the paradox is something like this…
Organisms (e.g. the Director and you dear reader) function as coherent purposeful entities, i.e. they have agency or consciousness. And that is really the distinguishing feature between living matter and non living matter. But the problem is that the things that we are made out of do not possess either agency or consciousness. Or do they? So the real question then becomes, what attributes are required of a system for that agency/consciousness to come about. And we could also ask, while we’re there, whether it’s the gene or the organism which is the ultimate driver of evolution.
Some, like our friend Professor Dawkins, will tell us that we don’t need to be concerned with this notion of agency/consciousness because it emerges from the bottom up, so to speak, as systems become more complex. But it seems to me that until we’re able to have that discussion about organisms as agents that have purposes, that have goals and that are able to operate on themselves and on their environment in order to achieve those goals then we’re missing the central point of what life is. But I sense the Director’s ship is sailing into biologically heretical and even querulous waters, so I will change course.
Another friend of the column, Iain McGilchrist, often talks about music and how it works, and I was thinking his comments there could very well chime with useful thoughts about this thing called life. He writes, for example, ‘Music – like narrative, like the experience of our lives as we live them – unfolds in time.’ So music, in essence, is experienced as a cohesive flow, not merely as isolated notes. McGilchrist suggests that music’s meaning, beauty, and emotional resonance emerge not from the isolated notes themselves but from the relationships, timing, and patterns that create something greater than what can be reduced to constituent parts. I could for example give you a categorisation of all the notes in a symphony but that wouldn’t be the symphony. If we overly focus on analysing the technical aspects like pitch, rhythm, intervals etc. we miss the point; what we might call the gestalt, the intangible and holistic experience that gives music its true power. In life, as in music, we must not forget the importance of context, interconnectedness, and the ineffable qualities of experience that cannot themselves be reduced to mere mechanics.
As you may know, the young Director played in a rock and roll band. My guitar of choice was a Fender Telecaster for reasons we don’t need to go into here. After one particularly enjoyable gig, I was approached backstage by a ‘fan’. She remarked what a beautiful tone the Fender Telecaster had. In response, I reached into my guitar case, picked the Telecaster up, held it to my ear and responded, ‘really? I can’t hear it’. Now, as I say, that was in the Director’s rock and roll days, and I like to think I would be a tad more gracious were it to happen today, but the point I think is relevant. Nothing comes to life, no matter how intricately constructed unless and until it is played.
Until next time, Happy Reading/Playing
Today’s Director’s Tip is sent in by a presumably excessively house-proud Mr S Spender. Thank you Mr Spender and keep them coming!
Empty tea bags make beautiful doilies for After Eight mints.