“Just like water,” they might say, and I would nod.
“Liquid, and transparent, with a density of 997 kilograms per meter cubed.”
“Sure,” I would reply.
“Which freezes and melts at exactly 0º Celsius, and which boils and condenses at exactly 100º Celsius.”
“Yyyyeahhhh,” I would say, uneasiness settling in
So assuming all the laws of physics are the same in this parallel world, you can’t have another water. Ok, but it’s a parallel world, so it need not have the same laws of physics.
But that’s not even the main problem: the XYZ thought experiment doesnt require XYZ to have identical fine grained properties to H2O, it just requires it to some superficial properties , like making up lakes and oceans .
The point is, those “superficial” properties prove to be much less superficial once you think about them at all. Like, the comment above is exactly the kind of loose handwaving that I’m trying to highlight. Even if you set aside stuff like density and molarity and just focus on “freezes and boils at roughly the right places, and occupies the same role in biology” it immediately falls apart as a possibility.
One can imagine a fantasy world where the world-dominating liquid is different from water but a real liquid (so it doesn’t crumble as a molecyle (the would be a argument that star garbage output mechanics might need changing and could fail to make sense))
If we ever find a planet with life that lives for example in a nitrogen sea I would think that the term “aquatic” should apply to them and in the sense of “sea animal” those would be “fish”.
And yeah this comes from the dolphin discussion part of my brain.
I think the point is that we first point at a “splashy stuff” that turns out later to have details such as made out of hydrogen. “splashy stuff” is not conceptually connnected to hydrogen because if those details were found out to be different it would still be “that splashy stuff”
Water is pretty figured out, but for example dark matter could be a number of different things. If one thinks of neutronic dark matter or axionic dark matter they would be different aqnd not equivalent to each other but they still succeed to be dark matter. And this kidn of thing doesn’t go away even if the thing is known better.
It also strikes me that under current understanding having a planet made out of anti-matter would locally behave similarly even if water and anti-water are not interexhangeable. And the XYZ issue is that anti-water would be water in the “splashy stuff that makes oceanic worlds” sense. Or a radical rephrasing would be that if sitting on a chair in the real world is hard to distinguish from sitting on a chair in a simulation/matrix then “chairness” is not dependent on the metaphysics of the situation (so matrix-water woudl alos be water even if it made from bits instead of atoms).
Of course heavy water is different to ordinary water . That’s not the point. The point is that in Putnam’s Twin Earth thought experiment, it is never asserted that XYZ is completely indistinguishable from water. The point is only that something similar sufficiently similar would have been called water when we started using the word thousands of years ago… thousands of years before a scientific understanding of water.
This sort of thing happens in our world too. For instance the “wasabi” available in the West is not wasabi.
The point of Poundstone’s exploration (which I independently endorse, having bought its claim) is that no such sufficiently similar substance can exist. That there’s a big gap between water and the next nearest physically possible alternative.
Heavy water being an example of something that would absolutely not fit the bill of “sufficiently similar” to water.
My concern, which I interpret as being TAG’s point (but with different words), is that your example of water vs. XYZ is immediately traceable (at least for anyone who knows the philosophical discussion) to Putnam’s Twin Earth experiment. The way you express your point suggests you disregard this thought experiment—which is surprising for someone acquainted with it, because Putnam (at least when he wrote the paper) would likely agree that a substance with the same basic chemical properties of water would be water. He actually aims to provide an argument for semantic externalism—i.e., the idea that the meaning of “water” (or of other natural species) is H20, its chemical nature, and not the apparent properties commonly used as criteria to discriminate it (that it’s a tasteless liquid...). He’s so pushing against a conventionalist view about semantics (and philosophy of language), thus it’s not about physics or ontology.
But we almost certainly are talking past each other , because Twin Earth isn’t really about water..it’s about naming and necessity . Any example where naming is contingent would have done .
So assuming all the laws of physics are the same in this parallel world, you can’t have another water. Ok, but it’s a parallel world, so it need not have the same laws of physics.
But that’s not even the main problem: the XYZ thought experiment doesnt require XYZ to have identical fine grained properties to H2O, it just requires it to some superficial properties , like making up lakes and oceans .
The point is, those “superficial” properties prove to be much less superficial once you think about them at all. Like, the comment above is exactly the kind of loose handwaving that I’m trying to highlight. Even if you set aside stuff like density and molarity and just focus on “freezes and boils at roughly the right places, and occupies the same role in biology” it immediately falls apart as a possibility.
(Given our physics.)
One can imagine a fantasy world where the world-dominating liquid is different from water but a real liquid (so it doesn’t crumble as a molecyle (the would be a argument that star garbage output mechanics might need changing and could fail to make sense))
If we ever find a planet with life that lives for example in a nitrogen sea I would think that the term “aquatic” should apply to them and in the sense of “sea animal” those would be “fish”.
And yeah this comes from the dolphin discussion part of my brain.
Sure, but one would not posit that this world looks just like Earth.
I think the point is that we first point at a “splashy stuff” that turns out later to have details such as made out of hydrogen. “splashy stuff” is not conceptually connnected to hydrogen because if those details were found out to be different it would still be “that splashy stuff”
Water is pretty figured out, but for example dark matter could be a number of different things. If one thinks of neutronic dark matter or axionic dark matter they would be different aqnd not equivalent to each other but they still succeed to be dark matter. And this kidn of thing doesn’t go away even if the thing is known better.
It also strikes me that under current understanding having a planet made out of anti-matter would locally behave similarly even if water and anti-water are not interexhangeable. And the XYZ issue is that anti-water would be water in the “splashy stuff that makes oceanic worlds” sense. Or a radical rephrasing would be that if sitting on a chair in the real world is hard to distinguish from sitting on a chair in a simulation/matrix then “chairness” is not dependent on the metaphysics of the situation (so matrix-water woudl alos be water even if it made from bits instead of atoms).
Can you imagine a planet where all the water is heavy water?
I can. I am not sure if that ability-to-imagine reflects the same sort of failure-to-notice-consequences.
EDIT: this would seem to indicate that it does.
Of course heavy water is different to ordinary water . That’s not the point. The point is that in Putnam’s Twin Earth thought experiment, it is never asserted that XYZ is completely indistinguishable from water. The point is only that something similar sufficiently similar would have been called water when we started using the word thousands of years ago… thousands of years before a scientific understanding of water.
This sort of thing happens in our world too. For instance the “wasabi” available in the West is not wasabi.
I think we’re talking past each other.
The point of Poundstone’s exploration (which I independently endorse, having bought its claim) is that no such sufficiently similar substance can exist. That there’s a big gap between water and the next nearest physically possible alternative.
Heavy water being an example of something that would absolutely not fit the bill of “sufficiently similar” to water.
My concern, which I interpret as being TAG’s point (but with different words), is that your example of water vs. XYZ is immediately traceable (at least for anyone who knows the philosophical discussion) to Putnam’s Twin Earth experiment. The way you express your point suggests you disregard this thought experiment—which is surprising for someone acquainted with it, because Putnam (at least when he wrote the paper) would likely agree that a substance with the same basic chemical properties of water would be water. He actually aims to provide an argument for semantic externalism—i.e., the idea that the meaning of “water” (or of other natural species) is H20, its chemical nature, and not the apparent properties commonly used as criteria to discriminate it (that it’s a tasteless liquid...). He’s so pushing against a conventionalist view about semantics (and philosophy of language), thus it’s not about physics or ontology.
Under which laws of physics?
But we almost certainly are talking past each other , because Twin Earth isn’t really about water..it’s about naming and necessity . Any example where naming is contingent would have done .