4 ms·

The periodic table is a human construct. So is the concept of an identifier.

xmcqdpt2 3y ago
Most elements are stable, especially most of the ones we deal with, and they fall in clear periods and rows based on chemical valence. This is true for main group elements and mostly true for transition metals. I think the periodic table was discovered, not invented. My guess is that whenever we communicate with some advanced alien species, the periodic table is going to be one of those things we share.
- TeMPOraL 3y ago
  Periodic table is recording multiple different patterns in atoms. Some better than others. By nature, its a dimensional reduction. There are many alternative renderings of the periodic table (or spiral, or cube, or ...) emphasizing different regularities. The one you refer to is just the most popular rendering.
rocqua 3y ago
The concept of an identifier comes with the concept of a bijection (or at least a injection). That is a truly basic concept in Mathematics. You could argue Mathematics is a human construction. But at that point, isn't every concept a human construction? In that case it is hardly helpful, or meaningful to say a concept is a human construct, since all concepts are.
- imtringued 3y ago
  The problem isn't the concept of a bijective function, it is picking the right function and that is a social problem.
jameshart 3y ago
I’d wager that nonhuman intelligences out there in the universe have analogous tables to the periodic table. And I suspect it would be possible for us to JOIN our periodic table onto theirs by matching on the atomic number field to create a mapping between, say, our names for the elements and theirs. That seems unlikely to be something we would be able to do with literally any other dataset that an alien civilization has. Their star catalog will contain many of the same objects ours does - but there won’t be an obvious key that lets us join them up. I guess there’s a few mathematical objects that would work - the list of Platonic solids maybe, or the symmetry groups… but in terms of real world physical things? Atomic numbers might be the only truly natural key there is.
- dkarl 3y ago
  The periodic table groups atoms by the number of protons they have and ignores other differences. Uranium 235 and Uranium 238 have the same "natural key" according to the periodic table. The periodic table is useful for solving a lot of problems, and for other problems where it doesn't work to treat U-235 and U-238 as the same, we (and other intelligences) use other ways of categorizing atoms.
  - jameshart 3y ago
    Right, but there’s a reason we call them ‘isotopes of Uranium’ rather than saying U-238, Np-238 and Pu-238 are isotopes in the ‘family of atoms with atomic mass 238’. Things with 92 protons in them behave chemically in similar ways. They form the same crystals and molecules. If you were building a table of isotopes you’d put a column for ‘proton count’, and you’d find lots of the properties of the isotopes depend on the proton count not the atomic mass. So you could normalize that table structure out and create another table with the atomic number as the key, and put all the properties that are common to all isotopes of a given element in that table. You would have made a table of elements and it would have the same primary key as the periodic table. That’s what a natural key is. One that emerges naturally when you normalize data you have collected. I suppose similarly ‘electrons in outer shell’ might emerge as a natural key by that process.
    - dkarl 3y ago
      I don't think that's what people mean when they say "natural key." People say "natural key" when they're talking about a unique identifier (that's the "key" part) that is part of the domain model of an object (the "natural" part.) If we drop the "unique identifier" aspect of a key, and we can distinguish between different objects that share the same value according to one key by using a different key, then anything can be a key. The number of pages in a book could be a "natural key." This conversation wouldn't exist if that's what people meant by "natural key," because the answer would be trivial.
      - TeMPOraL 3y ago

Most elements are stable, especially most of the ones we deal with, and they fall in clear periods and rows based on chemical valence. This is true for main group elements and mostly true for transition metals. I think the periodic table was discovered, not invented. My guess is that whenever we communicate with some advanced alien species, the periodic table is going to be one of those things we share.

TeMPOraL 3y ago
Periodic table is recording multiple different patterns in atoms. Some better than others. By nature, its a dimensional reduction. There are many alternative renderings of the periodic table (or spiral, or cube, or ...) emphasizing different regularities. The one you refer to is just the most popular rendering.

rocqua 3y ago

The concept of an identifier comes with the concept of a bijection (or at least a injection). That is a truly basic concept in Mathematics. You could argue Mathematics is a human construction. But at that point, isn't every concept a human construction? In that case it is hardly helpful, or meaningful to say a concept is a human construct, since all concepts are.

imtringued 3y ago
The problem isn't the concept of a bijective function, it is picking the right function and that is a social problem.

jameshart 3y ago

I’d wager that nonhuman intelligences out there in the universe have analogous tables to the periodic table. And I suspect it would be possible for us to JOIN our periodic table onto theirs by matching on the atomic number field to create a mapping between, say, our names for the elements and theirs. That seems unlikely to be something we would be able to do with literally any other dataset that an alien civilization has. Their star catalog will contain many of the same objects ours does - but there won’t be an obvious key that lets us join them up. I guess there’s a few mathematical objects that would work - the list of Platonic solids maybe, or the symmetry groups… but in terms of real world physical things? Atomic numbers might be the only truly natural key there is.

dkarl 3y ago
The periodic table groups atoms by the number of protons they have and ignores other differences. Uranium 235 and Uranium 238 have the same "natural key" according to the periodic table. The periodic table is useful for solving a lot of problems, and for other problems where it doesn't work to treat U-235 and U-238 as the same, we (and other intelligences) use other ways of categorizing atoms.
- jameshart 3y ago
  Right, but there’s a reason we call them ‘isotopes of Uranium’ rather than saying U-238, Np-238 and Pu-238 are isotopes in the ‘family of atoms with atomic mass 238’. Things with 92 protons in them behave chemically in similar ways. They form the same crystals and molecules. If you were building a table of isotopes you’d put a column for ‘proton count’, and you’d find lots of the properties of the isotopes depend on the proton count not the atomic mass. So you could normalize that table structure out and create another table with the atomic number as the key, and put all the properties that are common to all isotopes of a given element in that table. You would have made a table of elements and it would have the same primary key as the periodic table. That’s what a natural key is. One that emerges naturally when you normalize data you have collected. I suppose similarly ‘electrons in outer shell’ might emerge as a natural key by that process.
  - dkarl 3y ago
    I don't think that's what people mean when they say "natural key." People say "natural key" when they're talking about a unique identifier (that's the "key" part) that is part of the domain model of an object (the "natural" part.) If we drop the "unique identifier" aspect of a key, and we can distinguish between different objects that share the same value according to one key by using a different key, then anything can be a key. The number of pages in a book could be a "natural key." This conversation wouldn't exist if that's what people meant by "natural key," because the answer would be trivial.
    - TeMPOraL 3y ago