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Physics and chemistry impose some serious constraints on all life forms. On earth we have convergent evolution, independent groups of species independently deve

Physics and chemistry impose some serious constraints on all life forms. On earth we have convergent evolution, independent groups of species independently develop similar solutions for a specific problem. Life on other planets will have similar problems, e.g. reproduction, locomotion and perception of its environment, and its solutions will probably be similar to the ones we have on earth.

kenjackson 5y ago
But changes in the environment and initial starting point can result in very different approaches. For example land mammals, reptiles and fish are quite different from each other. Because they've "always been here" we don't appreciate how different they are. Imagine if we had no fish and then found a planet with water that had fish in it -- that would seem absolutely shocking to see animals that could breathe underwater.
- godelski 5y ago
  Honestly this would be pretty hard to imagine. Even if we had no concept of fish (which I find extremely unlikely given other evolutionary pressures, physics, and mechanics of life, but let's not go there) we would think "birds, but in a denser fluid." I don't think this would be "absolutely shocking" to biologists of that planet. Similarly like how biologists here have predicted methane based lifeforms. Now if we were talking about a fluid like sulfuric acid then yeah, that would be absolutely shocking, but not for the reasons of breathing (it's about electrons).
  - state_less 5y ago
    And all these animal/alien minds swim through time like a fish swims through water. Reminds me of that David Foster Wallace joke. > There are these two young fish swimming along, and they happen to meet an older fish swimming the other way, who nods at them and says, “Morning, boys. How’s the water?” And the two young fish swim on for a bit, and then eventually one of them looks over at the other and goes, “What the hell is water?” https://www.newyorker.com/books/page-turner/this-is-water https://www.newyorker.com/books/page-turner/this-is-water
- NotSwift 5y ago
  Both mammals and reptiles that live in the water use very similar methods even though they are not at all closely related. It is an example of convergent evolution.
ivoras 5y ago
First we need to decide how intelligent are the dolphins, then let us look at the stars. Every single life form on Earth today had exactly the same time to do its evolution in. Us, bats, dolphins, tapeworms, birch trees, amoeba, mushrooms, all of that had exactly the same chance(s) in the same time span. And we don't even know if and how mushrooms and trees communicate, let alone if they "think", for our near-sighted definition of thoughts. We don't even know what to make of birds, e.g. crows, with respect to the size of their brains and what they can do. Is our planet, taken as a whole, alive, in some form of the Gaia hypothesis? The correct answers as of this time are either "we don't know" or "it depends on the definition of alive." That Star Trek trope of "everything in the Universe is just like us with different faces" really needs to be put to rest. Even H.R. Giger was boring and unimaginative with regards to how he envisioned the Alien. That's clearly a creature influenced by Earth-ism - a quadruped, with a single head and mouth and a flexible spine and claws, it's basically a weird cat.
- rendall 5y ago
  Indeed. If there were civilizations that communicate on geological time scales, how would we even know they are alive? If whales and dogs and bats are too alien to communicate with, what hope do we have with aliens?
- alluro2 5y ago
  Completely agree - the vast differences in the Earth's species and their intelligence should be an indication of the enormous range of possibilities we should expect...Saying that, since "most intelligent" species on Earth are bipedal, it means it's most likely intelligent aliens would be too, does not only seem ignorant to the sheer number of factors and possibilities, but also to other species on Earth and ways intelligence can be manifested.
- acituan 5y ago
  > Every single life form on Earth today had exactly the same time to do its evolution in. Us, bats, dolphins, tapeworms, birch trees, amoeba, mushrooms, all of that had exactly the same chance(s) in the same time span. This is patently false as these species have very different places within the phylogenetic tree. Emphasis on tree, since their adaptivity experiments did not have a linear timeline either; we didn’t evolve to have speech from scratch, we’ve adopted existing partial solutions, e.g. having a tongue, to develop it. And we don’t need to delve into phenomenology of being a mushroom, adaptivity gives us an observable proxy to the “intelligence” of an organism; how general and efficient of a problem solver they are, the ultimate problem being surviving genes onward. Turns out humans do exceptionally well, for the problems they’ve encountered so far. We’ll see if/how we can solve anthropogenic coordination problems of our day. > That Star Trek trope of "everything in the Universe is just like us with different faces" really needs to be put to rest. You need to cook a "complex adaptive organism" solution with the same periodic table and a handful of forces. It's like coding a CRUD application with slightly different sub-requirements and the exact same programming language. How different can they be? If you need more creativity you have to break apart from physical requirements and the right genre for that is fantasy.
vagrantJin 5y ago
> Physics and chemistry impose some serious constraints on all life forms. On earth's carbon based life forms you mean. Its a huge blindspot, basically monkeys looking for other monkeys. If we believe our life is sufficiently compelex biochemically, it figures that other "life" may have the same complexity but with very different structures. So the argument for ET life to have almost exact homologs of terrestial life is bordering on naievete at best, and dangerously intolerant at worst.
- 542354234235 5y ago
  No, its more like saying “our star and the planets and most satellites in the solar system are generally spherical due to gravity. I postulate that all stars and planets in the universe are subject to those same forces and will also generally be spherical”. That isn’t a dangerously intolerant idea. We can say that life is unlikely to arise from a solid block of iron, due to what we understand about the atomic properties of iron, the possible chemical reactions, etc. There just isn’t much going on at a basic physics level for it to “do” anything that could likely lead to even the most generous definition of “life”. That isn’t naivete. It is your kind of fantastical thinking that life somewhere else somehow isn’t subject to the same physics as life here that is naive. It’s not wanting to be bound by boring concepts like chemical reactions, gravity, perceiving your environment in some way, etc. We don’t take people seriously that say that stars in other galaxies are actually the heads of long bright snakes and us thinking they are just boring balls of gas is our “blindspot”.
  - vagrantJin 5y ago
    We know a lot about physics. We don't know factually if a beetle can think and remember. We know about proteins. We don't know how some aquatic life can survive in the mariana trench. Biochemistry is indeed chemistry but it isn't as straight forward as we'd like to imagine. Till this day there are cell structures we are uncertain of and would be completely wandering in the dark were it not for cheap but powerful computation available 24/7. Lets go smaller and things get blurry. The standard model looks...hmmm.
    - 5y ago
bmitc 5y ago
> Physics and chemistry impose some serious constraints on all life forms. What are those constraints? Can you enumerate some of them? Also, physics and chemistry change under certain environments.

kenjackson 5y ago

But changes in the environment and initial starting point can result in very different approaches. For example land mammals, reptiles and fish are quite different from each other. Because they've "always been here" we don't appreciate how different they are. Imagine if we had no fish and then found a planet with water that had fish in it -- that would seem absolutely shocking to see animals that could breathe underwater.

godelski 5y ago
Honestly this would be pretty hard to imagine. Even if we had no concept of fish (which I find extremely unlikely given other evolutionary pressures, physics, and mechanics of life, but let's not go there) we would think "birds, but in a denser fluid." I don't think this would be "absolutely shocking" to biologists of that planet. Similarly like how biologists here have predicted methane based lifeforms. Now if we were talking about a fluid like sulfuric acid then yeah, that would be absolutely shocking, but not for the reasons of breathing (it's about electrons).
- state_less 5y ago
  And all these animal/alien minds swim through time like a fish swims through water. Reminds me of that David Foster Wallace joke. > There are these two young fish swimming along, and they happen to meet an older fish swimming the other way, who nods at them and says, “Morning, boys. How’s the water?” And the two young fish swim on for a bit, and then eventually one of them looks over at the other and goes, “What the hell is water?” https://www.newyorker.com/books/page-turner/this-is-water https://www.newyorker.com/books/page-turner/this-is-water
NotSwift 5y ago
Both mammals and reptiles that live in the water use very similar methods even though they are not at all closely related. It is an example of convergent evolution.

ivoras 5y ago

First we need to decide how intelligent are the dolphins, then let us look at the stars. Every single life form on Earth today had exactly the same time to do its evolution in. Us, bats, dolphins, tapeworms, birch trees, amoeba, mushrooms, all of that had exactly the same chance(s) in the same time span. And we don't even know if and how mushrooms and trees communicate, let alone if they "think", for our near-sighted definition of thoughts. We don't even know what to make of birds, e.g. crows, with respect to the size of their brains and what they can do. Is our planet, taken as a whole, alive, in some form of the Gaia hypothesis? The correct answers as of this time are either "we don't know" or "it depends on the definition of alive." That Star Trek trope of "everything in the Universe is just like us with different faces" really needs to be put to rest. Even H.R. Giger was boring and unimaginative with regards to how he envisioned the Alien. That's clearly a creature influenced by Earth-ism - a quadruped, with a single head and mouth and a flexible spine and claws, it's basically a weird cat.

rendall 5y ago
Indeed. If there were civilizations that communicate on geological time scales, how would we even know they are alive? If whales and dogs and bats are too alien to communicate with, what hope do we have with aliens?
alluro2 5y ago
Completely agree - the vast differences in the Earth's species and their intelligence should be an indication of the enormous range of possibilities we should expect...Saying that, since "most intelligent" species on Earth are bipedal, it means it's most likely intelligent aliens would be too, does not only seem ignorant to the sheer number of factors and possibilities, but also to other species on Earth and ways intelligence can be manifested.
acituan 5y ago
> Every single life form on Earth today had exactly the same time to do its evolution in. Us, bats, dolphins, tapeworms, birch trees, amoeba, mushrooms, all of that had exactly the same chance(s) in the same time span. This is patently false as these species have very different places within the phylogenetic tree. Emphasis on tree, since their adaptivity experiments did not have a linear timeline either; we didn’t evolve to have speech from scratch, we’ve adopted existing partial solutions, e.g. having a tongue, to develop it. And we don’t need to delve into phenomenology of being a mushroom, adaptivity gives us an observable proxy to the “intelligence” of an organism; how general and efficient of a problem solver they are, the ultimate problem being surviving genes onward. Turns out humans do exceptionally well, for the problems they’ve encountered so far. We’ll see if/how we can solve anthropogenic coordination problems of our day. > That Star Trek trope of "everything in the Universe is just like us with different faces" really needs to be put to rest. You need to cook a "complex adaptive organism" solution with the same periodic table and a handful of forces. It's like coding a CRUD application with slightly different sub-requirements and the exact same programming language. How different can they be? If you need more creativity you have to break apart from physical requirements and the right genre for that is fantasy.

vagrantJin 5y ago

> Physics and chemistry impose some serious constraints on all life forms. On earth's carbon based life forms you mean. Its a huge blindspot, basically monkeys looking for other monkeys. If we believe our life is sufficiently compelex biochemically, it figures that other "life" may have the same complexity but with very different structures. So the argument for ET life to have almost exact homologs of terrestial life is bordering on naievete at best, and dangerously intolerant at worst.

542354234235 5y ago
No, its more like saying “our star and the planets and most satellites in the solar system are generally spherical due to gravity. I postulate that all stars and planets in the universe are subject to those same forces and will also generally be spherical”. That isn’t a dangerously intolerant idea. We can say that life is unlikely to arise from a solid block of iron, due to what we understand about the atomic properties of iron, the possible chemical reactions, etc. There just isn’t much going on at a basic physics level for it to “do” anything that could likely lead to even the most generous definition of “life”. That isn’t naivete. It is your kind of fantastical thinking that life somewhere else somehow isn’t subject to the same physics as life here that is naive. It’s not wanting to be bound by boring concepts like chemical reactions, gravity, perceiving your environment in some way, etc. We don’t take people seriously that say that stars in other galaxies are actually the heads of long bright snakes and us thinking they are just boring balls of gas is our “blindspot”.
- vagrantJin 5y ago
  We know a lot about physics. We don't know factually if a beetle can think and remember. We know about proteins. We don't know how some aquatic life can survive in the mariana trench. Biochemistry is indeed chemistry but it isn't as straight forward as we'd like to imagine. Till this day there are cell structures we are uncertain of and would be completely wandering in the dark were it not for cheap but powerful computation available 24/7. Lets go smaller and things get blurry. The standard model looks...hmmm.
  - 5y ago

bmitc 5y ago

> Physics and chemistry impose some serious constraints on all life forms. What are those constraints? Can you enumerate some of them? Also, physics and chemistry change under certain environments.