Are Living Systems Machines?

Seems relevant to the topic at hand:

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No, I don’t think they can.

I’m not a reductionist. And the meaning of “natural mechanisms” is far from clear.

Right now, there are mechanical/physical and chemical reactions taking place in my body, that involve molecules which were not even part of my body as recently as yesterday.

A comment from my current reading in Heisenberg’s Physics and Philosophy, which gets added to my “must read” list of clearsighted scientists along with Eddington’s The Nature of the Physical World and Polanyi’s Personal Knowledge.

Heisenberg, more or less in as many words, says that quantum theory cannot be adequately described under materialistic categories (and he is scathing about the Cartesian system’s failures in this regard).

As I’ve mentioned on another thread (or two!) he frequenetly describes quantum uncertainty in terms of Aristotelian potentia, which have no place in the efficient causation and inert matter of classical science, but which (if you have a minimal grasp of Aquinas) reduces the paradoxical element considerably, despite the quantum world’s strangeness.

Now, he goes on to suggest (albeit from 1950s perspective) that there are likely to be things in living systems just as intractable to materialist reductions, and describes the division of biology into camps of those pursing to reduce life to chemistry, and those with whom he evidently feels more sympathy, who are looking for the equivalent of the “odd quantum world” in biology. Notably, the former in our century are heavily entrenched as the mainstream, and the others are the outsiders - even the pseudoscientists.

Now it’s one thing to say that there is not good evidence of design in living things: there could be methodological or evidential reasons for this, or it may be absent, even though nearly universally intuited.

But it’s quite another to say that there is no definition of design that scientists can use, because there is absolutely no doubt that it exists and can be observed, because it is what scientists do for a living. Design in human affairs is an empirical fact.

If an empirical fact cannot be described adequately or tractably, the problem is likely to be that science is using an inadequate language for it, ust as the language of inert matter subject to deterministic laws turns quantum physics into a bizarre paradox.

Quantum physics at least has the advantage that one can manipulate relatively simple equations and simply ignore the queerness, but what if the more important processes of life, which are indisputably many orders of magnitude more complex, cannot be reduced to any useful mathematics? Perhaps only some verbal expression of the issues is possible, but that the relevant language is as far from the usual materialist jargon as Aristotelian potencies are?

In that case, maybe scientists may just need to learn to work with the intuitive concept of design that they use when designing experiments, designing theories, designing lecture presentations, and so on and so forth. This would be because of the dictates of the subject matter, not because the subject itself is beyond investigation.

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How is that pertinent.
You say you are not a reductionist… so are you claiming that some biological systems cannot be explained naturally?

Do you know about the delphic boat?

He is pointing out that there are emergent properties that are independent of lower level details. He is right.

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More likely that we do not know enough about the lower level details to predict emergent properties…

It implies that a reductionist account of a single person would need to be a reductionist account of the entire cosmos.

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Life is physics and chemistry. That is to say, we are pretty certain that the reactions and interactions inside living organisms do not break any known law of physics. Personally, I don’t take issue with the notion that cells can be described mechanistically. There are, however, lots of very small details, many we can’t presently measure and cannot model that can make very big differences. So, one can invoke thermodynamics and entropy, because that certainly has a strong role, perhaps penetrating to the organismal level, and one can invoke chaos in modeling, again because their are parts of life and biochemical interactions where that’s appropriate. Self-organized, non-equilibrium, energy dissipative systems, is not an inappropriate way of looking at life, at some particular levels.

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Those two sentences do not mean the same thing. This post is not physics and chemistry, but does not break any known law, either.


OK. I see that. “Life comports to the laws of physics and chemistry.”

In my work as a biological scientist, I tend to work with the assumption that life is a phenomenon of physics/chemistry. That may be wrong, but scientifically, that’s how it goes.

To be honest, I can’t know for sure that it’s not an epiphenomenon or emergent from the properties of universe. So, physics + initial conditions might be sufficient for your post. I think the question defies proof either way at this time.

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That would depend on the definition of “machine”. For example this definition: e (1) an assemblage of parts that transmit forces, motion, and energy one to another in a [predetermined] manner from Merriam-Webster says that living systems are machines

And this one: 2a. a living organism or one of its functional systems says it all

It looks like most dictionaries say that living organisms are machines. I haven’t looked through all of them.

The only argument I can find to the contrary is: Organisms or Machines? | PLOS Synthetic Biology Community

A machine is extrinsically purposive in the sense that it works/functions towards an end that is external to itself; that is, it does not serve its own interests but those of its maker or user. An organism, on the other hand, is intrinsically purposive in the sense that its activities are directed towards the maintenance of its own organization; that is, it acts on its own behalf.

It does seem like a semantic quibble, though. Should we rename the field of biomechanics and restructure kinesiology?

Speaking purely to the question of organisms as machines, and nothing else, surely this view stems directly from the teaching Descartes which set the trajectory of modern science, even as individual findings militate against it.

Arguing that only the human mind (resc ogitans), created by God, is immaterial, and the rest of creation is inert matter (res extensa), animals were necessarily simply automatons.

This explains the calaier attitudes to vivisection amongst many scientists well into the 19th century and beyond: they had the principles of science on their side. The reaction against vivisection is an interesting history, often with the professional physiologists defending it on Cartesian grounds, and less scientifically rigorous medics attacking its cruelty on compassionate grounds.

Anti-vivisection laws controlled animal suffering, and currently there is a tendency to play up the sentience of animals (sometimes to extremes), but meanwhile, the molecular biology movement inherits Cartesian assumptions about the nature of life as something reducible to chemistry and ultimately to physics.

Clearly, machine-like systems are involved in life - which has been known ever since amputees wore wooden legs or Egyptians had false teeth. But the Aristotelian science that Descartes deliberately denied insists that living orgianisms are, primarily, holistic entities (called substantial forms). The parts all function towards the ends of the whole, and are not merely interlocked systems of mechanical or chemical artifacts. This remains a minority view amongst some, including the structuralists - but the research money is in the molecules and the machines.

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With that definition, it seems a stretch to say that a living organism is a machine. I see an organism as a process or system of processes, rather than as an assemblage.

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Of course it is. We research what we can. We tend to mine in areas considered more tractable. Barbara McClintock had a ‘feel for the organism’ (corn), but she investigated transposons with a reductionist approach. I’ve had a feel for E. coli, growing and working with it under a variety of conditions. I could tell by smell what media it was growing in and its stage of growth. And I studied how it altered and regulated its metabolism in response to different growth conditions, at the molecular level and above. A holistic appreciation is important in understanding what your models and investigation of the “little bits” need to lead toward and contribute to an explanation. It’s a picture of the larger terrain that your local models need to conform to. But holism doesn’t mean that the model will never accurately describe the larger phenomena. It may be hard to accomplish or technically impossible, but in science we don’t throw up our hands, declare “Here there be dragons” and stop trying.


It seems to me that scientific investigation of life does not include.more than physical/chemical processes and their consequences.

Treating life as machines might be a step up… as you will also acknowledge and investigate the design involved. I don’t expect to find a “ghost” in the cell… However there is thought put into it.

Hi Neil, thank you for your response. I offer a rebuttal:

A system of processes would be an assemblage- ** 2 : the act of [assembling] the state of being [assembled], which leads to ** 1 to bring together (as in a particular place or for a particular purpose)

And it remains that a process or system of processes needs a means of being carried out/ being implemented. It so happens that in living organisms that includes an assemblage of parts that transmit forces, motion, and energy one to another in a [predetermined] manner

We are clearly physical beings- the parts would be the organs, tissues, bones, systems etc., all assembled and working in a predetermined manner. All of the systems require an assemblage of parts that transmit forces, motion and energy one to another in a predetermined manner. The nervous system provides the voltage and the proper muscles with their supply of calcium (cat)ions respond to do the work. We are powered by electricity. Take away our (wet) electricity and all functions stop.

Even at the molecular level we see that, for example, ATP synthase is an assemblage of parts that transmit forces, motion and energy one to another in a predetermined manner. It isn’t a metaphor to call it a protein machine. You would have to invent new words that have the same meaning as the words we now use in order to describe what we observe in biology.

So no stretch required, Neil. Just an understanding of what is at play. Take a kinesiology course or two. Read an anatomy and physiology book- it isn’t any stretch at all to see that living organisms are an assemblage of parts that transmit forces, motion, and energy one to another in a [predetermined] manner. There really isn’t any other logical way of looking at them.

@swamidass- I have 11 hours before I can reply normally- No, I do not think that I am a robot. There isn’t anything in the definition of machine that says anything about that. Just because our systems fit the definition doesn’t mean we aren’t conscious or don’t have free will. We do still reproduce.

@JoeG you think you are just a robot?

A dead person, immediately after death, is the same assemblage of parts as before death. What has changed, are the processes.

In any case, this argument is pointless. “Machine” is not defined precisely enough to settle the question on the basis of the definition.

If you want to see a living system as a machine, that’s your choice. For me, it just doesn’t match what I expect of a machine.


The question is not what we see living organisms as… the question is what science can see about life.
Can science explain death in any way other than a machine and systems failing?
I sometimes look at scientific explanations of reality as slightly out of phase with it… living organisms are not machines… all of us including scientists know that… however can the scientific method see anything more than machines…
I think answering this question is important before we take scientific “facts” into consideration when doing theology.

I’m not sure that “machine” is even a technical term in science. It’s more of a casual term. Scientific explanations are often oversimplifications, but an oversimplification is often more useful than a fully detailed account.

Anyway, for perspective, I’ll stick my neck out and say that an automobile is not a machine. It is mainly a machine, but not completely a machine. It’s operation depends on a combustion process, and that combustion process is not something that I would consider a machine.

If we compare to a living organism, then there are mechanical systems throughout, but there is also a distributed system of thermodynamic processes (roughly analogous to the combustion process of the automobile).

As for what we can say about life – I’m not sure we will ever have a complete answer to that. Finding life elsewhere in the cosmos would help. Yes, biochemistry tells us a lot about living systems. But we don’t know enough that we could design a wholly original living system.

I should note that I’m a mathematician, not a biologist.