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The problem is we're dealing with real objects, conflating real objects and mathematical objects is begging the question against the person saying we need haecc

The problem is we're dealing with real objects, conflating real objects and mathematical objects is begging the question against the person saying we need haecceity (also called "thisness" - the property of being "this" thing and not "that" thing). If real objects are just like mathematical objects then all they are is bundles of properties: object A is no more than the set of properties that can be ascribed to A. There are a few problems with that, but here's an interesting one. Consider a world in which there are only two identical iron spheres, say 1 mile wide, 1 mile apart from each other. Now each sphere has exactly the same properties - are they the same spheres? Most people would say no. So what individuates them? Well, some property that makes it the case that one sphere is that sphere and not any other. To put it in your terminology, for every boolean function f(x) which is true iff x has property f and false if it doesn't have f (eg. IsIron(x) = True), then both spheres have exactly the same set of true/false values for all properties (forall f.). Unless we introduce a haeecity functions: a(x = A) = True for A, b(x = B) = True for B - ie. properties which are only true when their arguments pick out the objects which they are about. Then we can distinguish between objects, because they have different values for haecities (property functions) a, b.

anentropic 12y ago
First time I have read anything about haecceity. The first thing that pops into my head regarding the two iron spheres is that they must differ in their position in the universe, so they differ in something other than their haecceity. If there is no way for two identical real objects to occupy the same space then maybe this concept never applies to real objects...?
- brudgers 12y ago
  The problem for a Midevalist is that location is an accidental property...transposing their locations does not make one the other and vice versa. Location as the basis for haecceity is numerical individuation of the sort Scotus rejects.
  - mjburgess 12y ago
    Well it's an "accidental" property for pretty much everyone today - very few people anything that would make spacial location a property of the thing. You'd have to say that if you translated the entire universe in one direction some property of everything would change - but everything would behave identically, all measurements would be identical, all relationships between objects identical, etc. A spacial property is at least as weird as haecceity.
    - brudgers 12y ago
      Programmers often make spatial location a property of an when using object oriented programming. As you observe, doing so makes translating the state of the entire universe more complex than it might otherwise be.
  - anentropic 12y ago
    Hmm... but in the real world there's no way to transpose their locations without moving continuously through intermediate positions, so at the end of the transpositions the two objects will have a different history of location and their identity can be observed throughout and thus preserved. If they could be transposed instantaneously they'd be indistinguishable. Although they would still have a different 'history of locations' property. Or are we saying the same thing? that there's no need for haecceity in the real world as there are always real properties that could be used to distinguish objects?
    - brudgers 12y ago
      The real world, so far as I am aware, does not consist entirely of two iron spheres. Moving the goalposts does not help clarify the reasoning nor refute the point about haecceity. That a person cannot tell two things apart is also accidental for the mediaeval philosopher. God can. Omniscience gets us the Locational history. Of course this means the universe contains three things: two spheres and God. That would be a given for any public opinions expressed by Scotus or his contemporaries. The obvious move to defeat Haecceity is to postulate a universe with two Gods. Alas, the medieval philosophy logically precludes this: Two omnipotentencies is a contradiction and the Council of Nicea dogmaticcally solved that a millennium before Scotus's time. If that's what you're saying then yes we are saying the same thing.
- SigmundA 12y ago
  This is the first thing I thought too, their position relative to the observer is a property of the object, it seems obvious. This applies to programming as well, in most OO languages two instances of a class with identical properties are still different due to their locations in memory. Most of these language have a distinction between value equal and reference equal. Also in databases you have the issue as well. Relational purist tend want natural keys for a item, but the reality is most database make artificial keys such that two items may have the same properties and are yet distinct due to the artificial key. For instance what is the natural key of a person? Even their DNA sequence may not be unique in the case of twins, or you may have incomplete information, either way you need to give them an artificial key. Much of seems to come down to the observer. In the case of the two spheres, two where observed and given a mental haecceitas instantly. If I examine the identical iron spheres then close my eyes and they are moved into opposite positions, then observe them again I will not be able to determine which is which or if they have changed. Computers are the same way they are typically recording facts and modelling things from the real world, imperfect models based on whats observed. What may be two objects may infact be one, a dup, etc..
thaumasiotes 12y ago
"Thisness"? It looks like "theseness" to me. :/ On a more serious note, the property that makes it so that one sphere is itself but is not the other is generally conceived of counterfactually. If I were to enter that universe and stand on one of the spheres, I would immediately suffocate. But, the sphere playing host to my corpse would be easily distinguishable from the other sphere. Similarly, it's easy to imagine scratching the surface of one of the spheres -- it seems unlikely, in that hypothetical world, that a symmetrical scratch would simultaneously develop on the opposed sphere. Assuming the spheres are in a conventional three-dimensional space, and that they are not perfectly uniform but contain irregularities at the atomic level, then they will necessarily be distinguishable from each other. All that's necessary is to look at their orientation to each other. Every atom in one sphere will correspond to an identical atom in the other sphere. But if they are "identical" in an absolute, 3-dimensional coordinates sense, then the atom on "sphere 1" (without loss of generality ;) ) that's closest to sphere 2 will correspond to the atom on sphere 2 that is farthest from sphere 1, which is an asymmetry. If they're mirrored, such that the closest atom on sphere 1 to sphere 2 corresponds to the closest atom to sphere 1 on sphere 2, then they are distinguishable from each other by reference to the euclidean arrangement of corresponding sets of atoms. (To say this another way, you'd have to rotate one of them to get it to be identical in terms of euclidean positioning -- or if they're really mirrored, it might be impossible to rotate one such that it matched the other in terms of euclidean positioning, which is a major difference.) If this hypothetical universe actually contained nothing but two perfectly uniform iron spheres, we could say a couple of things: 1. Sure, there's no real method of distinguishing one sphere from the other sphere. But, 2. This universe does not obey the same physical laws as our universe, so there's no real reason to expect it to have the same haecceic properties. 3. Furthermore, there are no lessons to be drawn from the two-iron-spheres universe that can be sensibly applied to the universe we live in.
- zem 12y ago
  but consider: if a sufficiently magical technology could make an atom-for-atom copy of the mona lisa, we would still feel that there was some quality that distinguished the original. the most satisfying solution I've seen is to consider an "object" as a four dimensional world line, elevating "position x at time t" to an intrinsic property. that keeps the two spheres distinct even if they swap positions, since they would never swap world lines.
sp332 12y ago
http://en.m.wikipedia.org/wiki/One-electron_universe http://en.m.wikipedia.org/wiki/One-electron_universe

anentropic 12y ago

First time I have read anything about haecceity. The first thing that pops into my head regarding the two iron spheres is that they must differ in their position in the universe, so they differ in something other than their haecceity. If there is no way for two identical real objects to occupy the same space then maybe this concept never applies to real objects...?

brudgers 12y ago
The problem for a Midevalist is that location is an accidental property...transposing their locations does not make one the other and vice versa. Location as the basis for haecceity is numerical individuation of the sort Scotus rejects.
- mjburgess 12y ago
  Well it's an "accidental" property for pretty much everyone today - very few people anything that would make spacial location a property of the thing. You'd have to say that if you translated the entire universe in one direction some property of everything would change - but everything would behave identically, all measurements would be identical, all relationships between objects identical, etc. A spacial property is at least as weird as haecceity.
  - brudgers 12y ago
    Programmers often make spatial location a property of an when using object oriented programming. As you observe, doing so makes translating the state of the entire universe more complex than it might otherwise be.
- anentropic 12y ago
  Hmm... but in the real world there's no way to transpose their locations without moving continuously through intermediate positions, so at the end of the transpositions the two objects will have a different history of location and their identity can be observed throughout and thus preserved. If they could be transposed instantaneously they'd be indistinguishable. Although they would still have a different 'history of locations' property. Or are we saying the same thing? that there's no need for haecceity in the real world as there are always real properties that could be used to distinguish objects?
  - brudgers 12y ago
    The real world, so far as I am aware, does not consist entirely of two iron spheres. Moving the goalposts does not help clarify the reasoning nor refute the point about haecceity. That a person cannot tell two things apart is also accidental for the mediaeval philosopher. God can. Omniscience gets us the Locational history. Of course this means the universe contains three things: two spheres and God. That would be a given for any public opinions expressed by Scotus or his contemporaries. The obvious move to defeat Haecceity is to postulate a universe with two Gods. Alas, the medieval philosophy logically precludes this: Two omnipotentencies is a contradiction and the Council of Nicea dogmaticcally solved that a millennium before Scotus's time. If that's what you're saying then yes we are saying the same thing.
SigmundA 12y ago
This is the first thing I thought too, their position relative to the observer is a property of the object, it seems obvious. This applies to programming as well, in most OO languages two instances of a class with identical properties are still different due to their locations in memory. Most of these language have a distinction between value equal and reference equal. Also in databases you have the issue as well. Relational purist tend want natural keys for a item, but the reality is most database make artificial keys such that two items may have the same properties and are yet distinct due to the artificial key. For instance what is the natural key of a person? Even their DNA sequence may not be unique in the case of twins, or you may have incomplete information, either way you need to give them an artificial key. Much of seems to come down to the observer. In the case of the two spheres, two where observed and given a mental haecceitas instantly. If I examine the identical iron spheres then close my eyes and they are moved into opposite positions, then observe them again I will not be able to determine which is which or if they have changed. Computers are the same way they are typically recording facts and modelling things from the real world, imperfect models based on whats observed. What may be two objects may infact be one, a dup, etc..

thaumasiotes 12y ago

"Thisness"? It looks like "theseness" to me. :/ On a more serious note, the property that makes it so that one sphere is itself but is not the other is generally conceived of counterfactually. If I were to enter that universe and stand on one of the spheres, I would immediately suffocate. But, the sphere playing host to my corpse would be easily distinguishable from the other sphere. Similarly, it's easy to imagine scratching the surface of one of the spheres -- it seems unlikely, in that hypothetical world, that a symmetrical scratch would simultaneously develop on the opposed sphere. Assuming the spheres are in a conventional three-dimensional space, and that they are not perfectly uniform but contain irregularities at the atomic level, then they will necessarily be distinguishable from each other. All that's necessary is to look at their orientation to each other. Every atom in one sphere will correspond to an identical atom in the other sphere. But if they are "identical" in an absolute, 3-dimensional coordinates sense, then the atom on "sphere 1" (without loss of generality ;) ) that's closest to sphere 2 will correspond to the atom on sphere 2 that is farthest from sphere 1, which is an asymmetry. If they're mirrored, such that the closest atom on sphere 1 to sphere 2 corresponds to the closest atom to sphere 1 on sphere 2, then they are distinguishable from each other by reference to the euclidean arrangement of corresponding sets of atoms. (To say this another way, you'd have to rotate one of them to get it to be identical in terms of euclidean positioning -- or if they're really mirrored, it might be impossible to rotate one such that it matched the other in terms of euclidean positioning, which is a major difference.) If this hypothetical universe actually contained nothing but two perfectly uniform iron spheres, we could say a couple of things: 1. Sure, there's no real method of distinguishing one sphere from the other sphere. But, 2. This universe does not obey the same physical laws as our universe, so there's no real reason to expect it to have the same haecceic properties. 3. Furthermore, there are no lessons to be drawn from the two-iron-spheres universe that can be sensibly applied to the universe we live in.

zem 12y ago
but consider: if a sufficiently magical technology could make an atom-for-atom copy of the mona lisa, we would still feel that there was some quality that distinguished the original. the most satisfying solution I've seen is to consider an "object" as a four dimensional world line, elevating "position x at time t" to an intrinsic property. that keeps the two spheres distinct even if they swap positions, since they would never swap world lines.

sp332 12y ago

http://en.m.wikipedia.org/wiki/One-electron_universe http://en.m.wikipedia.org/wiki/One-electron_universe