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Here's a controversial view, but any good comments section needs a few of them: Viruses are no more "life" than bacteria are "life" or amoeba are "life" or ant

Here's a controversial view, but any good comments section needs a few of them: Viruses are no more "life" than bacteria are "life" or amoeba are "life" or ants are "life" or mice are "life" or humans are "life"... We're all just chemical machines, nothing more nothing less. Giving the word 'life' some special significance is misleading and confusing. In order to not confuse ourselves we should be talking about functions and descriptions of those functions as implemented among chemical machines. Do viruses reproduce? Yes, by hijacking cellular machinery. Do bacteria reproduce? Yes, by cloning themselves. ... This sort of thinking about the world allows us to stay close to reality without abstract and ultimately meaningless distractions like 'life'. Heaving the burden of abstraction onto 'reproduce' is still dangerous, but much less so than allowing 'life' to lurk as an abstract category in our minds.

filoeleven 9y ago
Is this not just picking a different abstraction? What is a “chemical” besides a collection of atoms? What is an “atom” except (some hand-wavey quantum stuff that I certainly don’t understand)? Why give primacy to the chemicals over the atoms or the quantum field? We could go the other direction too, and consider it significant that we are a tiny part of a giant living body that is the planet. Does it stop there? Could we comprehend it if Earth itself was a part of some vast active living intelligent system, in the same way that we believe a bacterium or a cell cannot conceive that it is part of our own human body, seeing it simply as “the environment”? It all gets fairly philosophical pretty quickly. I certainly don’t have any answers, but I will say that I find it a little suspicious how when we move far enough in any direction from the scale we ourselves operate on, our understanding of how things work devolves rapidly towards relatively simple deterministic or probabilistic equations, while our own life experience is rich and rooted in desires and decision-making.
ajnin 9y ago
By that definition you could say that pretty much anything that does something is a machine. A computer is an electrical machine, the Sun is a physical machine ... We choose to give specific names like "computer" or "star" or "life" to physical phenomenons which fit a particular definition. It's mostly a way for us humans ot communicate and think about it. Life exists because we made up a word for it.
Retra 9y ago
While I totally agree with you, there is some value in having a clear definition of life if you're trying to do something like determine if it exists on other planets. In that sense, you're looking for some kind of self-separating chemical unit, which looks very different from a homogenous soup which happens to undergo complex chemical reactions.
Synaesthesia 9y ago
The problem with that analogy IMO is that machines can be comprehended by humans, whereas even the most primitive forms of life are more sophisticated than anything human created. Reproduction is an astonishing feat in itself - if only we could create a machine which could reproduce, but it's not so simple!
- cobbzilla 9y ago
  Reproduction is easy, and was done in software, on the Internet, in 1988 [1]. There is a lot more to life than mere replication, for example homeostasis. The Morris Worm did not make any efforts to maintain homeostasis, and thus became extinct relatively quickly. [1] https://en.wikipedia.org/wiki/Morris_worm https://en.wikipedia.org/wiki/Morris_worm
  - Synaesthesia 9y ago
    A physical man made object that can reproduce itself though - that is an incredible challenge.
- PeterisP 9y ago
  If we define reproduction as equivalent to how viruses reproduce (i.e. by repurposing machinery of cells to reproduce themselves), then we have created such machines; "built from scratch" human-made viruses exist consisting of synthetic DNA/RNA.
taneq 9y ago
I thought this article was a very interesting take on the subject: https://blogs.scientificamerican.com/brainwaves/why-life-does-not-really-exist/ https://blogs.scientificamerican.com/brainwaves/why-life-doe...
cobbzilla 9y ago
One of the (many and oft-debated) aspects of life is that via homeostasis it maintains a negative entropy gradient. That is, over time, it will coalesce more "order" within itself than the 2nd Law of Thermodynamics says should normally happen -- more than if it were merely a random bag of chemicals. I like this definition, because it implies some kind of "trying" -- life must "try" to keep some balance that continues its existence. (a) Viruses (and certain bacteria) confound this approach because they can indefinitely continue (and even evolve) their existence without actively maintaining or improving any kind of this "balance"; they rely on their host to provide the balance, or at least some critical parts of it (if by definition, they cannot exist outside a host). (b) Does this make them life? Unclear, maybe. (c) Could such an organism evolve to no longer depend on a host? Yes, conceivable. (d) Would this organism that maintains homeostasis on its own be considered life? I would venture to say yes. So at what point during the evolution from (a) to (d) did this organism become "life"? It seems like it is just semantics at that point. Pick your criterion, call it life.
- snissn 9y ago
  I think a virus has much lower entropy than a cell. It's tightly packed, ordered and semi-crystal-like. Viruses make more viruses. I think they may be winning if you measure them by creating pockets of deceased entropy!
Clanan 9y ago
From the philosophical side, one of the reasons we attach such abstractions to "life" is to avoid reducing it to a basic functional definition. i.e. we should not equate ant life with human life. Especially in the sciences, it's an important moral/ethical consideration.

filoeleven 9y ago

Is this not just picking a different abstraction? What is a “chemical” besides a collection of atoms? What is an “atom” except (some hand-wavey quantum stuff that I certainly don’t understand)? Why give primacy to the chemicals over the atoms or the quantum field? We could go the other direction too, and consider it significant that we are a tiny part of a giant living body that is the planet. Does it stop there? Could we comprehend it if Earth itself was a part of some vast active living intelligent system, in the same way that we believe a bacterium or a cell cannot conceive that it is part of our own human body, seeing it simply as “the environment”? It all gets fairly philosophical pretty quickly. I certainly don’t have any answers, but I will say that I find it a little suspicious how when we move far enough in any direction from the scale we ourselves operate on, our understanding of how things work devolves rapidly towards relatively simple deterministic or probabilistic equations, while our own life experience is rich and rooted in desires and decision-making.

ajnin 9y ago

By that definition you could say that pretty much anything that does something is a machine. A computer is an electrical machine, the Sun is a physical machine ... We choose to give specific names like "computer" or "star" or "life" to physical phenomenons which fit a particular definition. It's mostly a way for us humans ot communicate and think about it. Life exists because we made up a word for it.

Retra 9y ago

While I totally agree with you, there is some value in having a clear definition of life if you're trying to do something like determine if it exists on other planets. In that sense, you're looking for some kind of self-separating chemical unit, which looks very different from a homogenous soup which happens to undergo complex chemical reactions.

Synaesthesia 9y ago

The problem with that analogy IMO is that machines can be comprehended by humans, whereas even the most primitive forms of life are more sophisticated than anything human created. Reproduction is an astonishing feat in itself - if only we could create a machine which could reproduce, but it's not so simple!

cobbzilla 9y ago
Reproduction is easy, and was done in software, on the Internet, in 1988 [1]. There is a lot more to life than mere replication, for example homeostasis. The Morris Worm did not make any efforts to maintain homeostasis, and thus became extinct relatively quickly. [1] https://en.wikipedia.org/wiki/Morris_worm https://en.wikipedia.org/wiki/Morris_worm
- Synaesthesia 9y ago
  A physical man made object that can reproduce itself though - that is an incredible challenge.
PeterisP 9y ago
If we define reproduction as equivalent to how viruses reproduce (i.e. by repurposing machinery of cells to reproduce themselves), then we have created such machines; "built from scratch" human-made viruses exist consisting of synthetic DNA/RNA.

taneq 9y ago

I thought this article was a very interesting take on the subject: https://blogs.scientificamerican.com/brainwaves/why-life-does-not-really-exist/ https://blogs.scientificamerican.com/brainwaves/why-life-doe...

cobbzilla 9y ago

One of the (many and oft-debated) aspects of life is that via homeostasis it maintains a negative entropy gradient. That is, over time, it will coalesce more "order" within itself than the 2nd Law of Thermodynamics says should normally happen -- more than if it were merely a random bag of chemicals. I like this definition, because it implies some kind of "trying" -- life must "try" to keep some balance that continues its existence. (a) Viruses (and certain bacteria) confound this approach because they can indefinitely continue (and even evolve) their existence without actively maintaining or improving any kind of this "balance"; they rely on their host to provide the balance, or at least some critical parts of it (if by definition, they cannot exist outside a host). (b) Does this make them life? Unclear, maybe. (c) Could such an organism evolve to no longer depend on a host? Yes, conceivable. (d) Would this organism that maintains homeostasis on its own be considered life? I would venture to say yes. So at what point during the evolution from (a) to (d) did this organism become "life"? It seems like it is just semantics at that point. Pick your criterion, call it life.

snissn 9y ago
I think a virus has much lower entropy than a cell. It's tightly packed, ordered and semi-crystal-like. Viruses make more viruses. I think they may be winning if you measure them by creating pockets of deceased entropy!

Clanan 9y ago

From the philosophical side, one of the reasons we attach such abstractions to "life" is to avoid reducing it to a basic functional definition. i.e. we should not equate ant life with human life. Especially in the sciences, it's an important moral/ethical consideration.