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Life is that which is subject to Darwinian evolution. That definition catches every single thing you'd call life, excludes all the things that clearly aren't,

by tbabb 7y ago

Life is that which is subject to Darwinian evolution. That definition catches every single thing you'd call life, excludes all the things that clearly aren't, disambiguates some grey cases, and illuminates one or two new phenomena to be life which you might not have realized. To be clear, Darwinian evolution means: - It makes copies of itself (reproduction) - The copies take traits from the original (inheritance) - The traits can vary among the copies and between generations (mutation) - The copies' ability to make more copies depends on the traits they inherit (selection)

Razengan 7y ago
> It makes copies of itself (reproduction) ... Again, what about species that don't reproduce themselves, but spawn from a single "factory"? That factory may be nothing like them. It could be a mechanical factory producing automatons (with human-level thought if you need that criteria), or a universally-unique "mother" creature, or even a non-sentient spawning pool where they spontaneously form every now and then. If there are entire planets populated by such entities, and they have governed over many things for as much time as we have occupied our Earth, would you still classify them as not-life in your dealings with them? That would be like not considering Taiwan a country. (Sorry, couldn't resist injecting contemporary political commentary.)
- tbabb 7y ago
  > or a single "mother" creature How did the "mother" creature come to be? By what mechanism did its complexity emerge? There is no known or plausible mechanism by which complex life can arise without evolution, and technology which does not change its design is (very appropriately) by the definition above, not life.
  - Razengan 7y ago
    > How did the "mother" creature come to be? It could be a human "mad scientist" creating hordes of Pikachus. Suppose the scientist has also attained biological immortality for himself, and the Pikachus have spread to multiple planets over thousands of years. You come upon such a colony planet, but you have no knowledge of their creator. They display no clues that hint at the scientist's role in their civilization (for a civilization it has become by now.) You cannot discern how the Pikachus are coming into existence. Would you classify them as life? Why not? How would your interactions with them and their interactions with the universe be fundamentally different than any other life you encounter? What if they were robotic instead of flesh-and-fur?
    - tbabb 7y ago
      I assume by "spreading" you mean that the Pikachus can reproduce? Can they mutate? If so, then they satisfy all four boxes and they count as life. If the Pikachus are made of cells, they'll certainly mutate/vary, since their heritable material is DNA, which is quite fragile. Really, it's hard to imagine having "reproduction" without "mutation" in the imperfect physical world where errors are possible— I can't imagine any copying process, even a technological one, which succeeds with perfect fidelity and 100% probability. So if you have #1, #3 is basically going to be a given, because the universe is imperfect. I don't think "what material they're made of" matters much, except that by definition flesh has to be alive, since it's made of things (cells) that tick all four boxes. If the Pikachus don't reproduce themselves, and/or are created with perfect fidelity every time, then yes, I would call them technology and not life. We certainly wouldn't say that iPads (Pikachus) coming from a factory ("mother creature") are alive.
      - Razengan 7y ago
        > I assume by "spreading" you mean that the Pikachus can reproduce? No, they're all created by the mad scientist but can think, reason, communicate, teach, interact, invent and construct perfectly fine on their own. > I don't think "what material they're made of" matters much ... If the Pikachus don't reproduce themselves, and/or are created with perfect fidelity every time, then yes, I would call them technology and not life. So, to distill your criteria for life, it comes down to: • Species must consist of "individuals" who join in pairs to produce another individual. • New individuals must be slightly different from the individuals who reproduced them. In other comment [0] you say that you could consider software to be alive: > Note that "alive" by the given definition doesn't imply "conscious" or "intelligent" > We certainly wouldn't say that iPads (Pikachus) coming from a factory ("mother creature") are alive. But if an iPad had a software process that connected to another iPad, and they both commanded the factory to create a new, slightly different iPad, would they be considered alive? :) [0] https://news.ycombinator.com/item?id=21231043 https://news.ycombinator.com/item?id=21231043
        tbabb 7y ago
jamiek88 7y ago
Certain genetic algorithms could fulfill this criteria. Could software be alive?
- tbabb 7y ago
  I'd say yes. Note that "alive" by the given definition doesn't imply "conscious" or "intelligent" (though that is certainly logically possible for software too, though I doubt that has happened yet).

by tbabb 7y ago

Razengan 7y ago

> It makes copies of itself (reproduction) ... Again, what about species that don't reproduce themselves, but spawn from a single "factory"? That factory may be nothing like them. It could be a mechanical factory producing automatons (with human-level thought if you need that criteria), or a universally-unique "mother" creature, or even a non-sentient spawning pool where they spontaneously form every now and then. If there are entire planets populated by such entities, and they have governed over many things for as much time as we have occupied our Earth, would you still classify them as not-life in your dealings with them? That would be like not considering Taiwan a country. (Sorry, couldn't resist injecting contemporary political commentary.)

tbabb 7y ago
> or a single "mother" creature How did the "mother" creature come to be? By what mechanism did its complexity emerge? There is no known or plausible mechanism by which complex life can arise without evolution, and technology which does not change its design is (very appropriately) by the definition above, not life.
- Razengan 7y ago
  > How did the "mother" creature come to be? It could be a human "mad scientist" creating hordes of Pikachus. Suppose the scientist has also attained biological immortality for himself, and the Pikachus have spread to multiple planets over thousands of years. You come upon such a colony planet, but you have no knowledge of their creator. They display no clues that hint at the scientist's role in their civilization (for a civilization it has become by now.) You cannot discern how the Pikachus are coming into existence. Would you classify them as life? Why not? How would your interactions with them and their interactions with the universe be fundamentally different than any other life you encounter? What if they were robotic instead of flesh-and-fur?
  - tbabb 7y ago
    I assume by "spreading" you mean that the Pikachus can reproduce? Can they mutate? If so, then they satisfy all four boxes and they count as life. If the Pikachus are made of cells, they'll certainly mutate/vary, since their heritable material is DNA, which is quite fragile. Really, it's hard to imagine having "reproduction" without "mutation" in the imperfect physical world where errors are possible— I can't imagine any copying process, even a technological one, which succeeds with perfect fidelity and 100% probability. So if you have #1, #3 is basically going to be a given, because the universe is imperfect. I don't think "what material they're made of" matters much, except that by definition flesh has to be alive, since it's made of things (cells) that tick all four boxes. If the Pikachus don't reproduce themselves, and/or are created with perfect fidelity every time, then yes, I would call them technology and not life. We certainly wouldn't say that iPads (Pikachus) coming from a factory ("mother creature") are alive.
    - Razengan 7y ago
      > I assume by "spreading" you mean that the Pikachus can reproduce? No, they're all created by the mad scientist but can think, reason, communicate, teach, interact, invent and construct perfectly fine on their own. > I don't think "what material they're made of" matters much ... If the Pikachus don't reproduce themselves, and/or are created with perfect fidelity every time, then yes, I would call them technology and not life. So, to distill your criteria for life, it comes down to: • Species must consist of "individuals" who join in pairs to produce another individual. • New individuals must be slightly different from the individuals who reproduced them. In other comment [0] you say that you could consider software to be alive: > Note that "alive" by the given definition doesn't imply "conscious" or "intelligent" > We certainly wouldn't say that iPads (Pikachus) coming from a factory ("mother creature") are alive. But if an iPad had a software process that connected to another iPad, and they both commanded the factory to create a new, slightly different iPad, would they be considered alive? :) [0] https://news.ycombinator.com/item?id=21231043 https://news.ycombinator.com/item?id=21231043
      - tbabb 7y ago

jamiek88 7y ago

Certain genetic algorithms could fulfill this criteria. Could software be alive?

tbabb 7y ago
I'd say yes. Note that "alive" by the given definition doesn't imply "conscious" or "intelligent" (though that is certainly logically possible for software too, though I doubt that has happened yet).