Rigid Designators

The example of a rigid designator most commonly offered is that of "Richard Nixon", which identifies a particular person. One descriptive phrase for the person "Richard Nixon" could be "the 37th President of the United States". However, there are possible worlds in which Nixon lost the election or died shortly after birth. In those possible worlds, "the 37th President of the United States" doesn't designate Nixon but some other person, e.g. Hubert Humphrey.

The claim made by Kripke and other proponents of rigid designators is that while the "37th President of the United States" only refers to Nixon in this possible world, the phrase "Richard Nixon" refers to Nixon in all possible worlds, even in worlds where Richard Nixon was assassinated as Vice President, died of pneumonia while serving in the senate, had a different name or was even born with some kind of congenital deformity making him unrecognizable to us.

My problem now is that I don't know how far to take this. At what point do I start identifying someone similar to Nixon as a different person instead of Nixon?

Imagine a possible world in which Nixon has an identical twin brother and are both given up for adoption. However, neither of them are named Richard and they both take on the surname of their adopted parents. One is Frank and the other is Fred. Neither of them enter politics. One becomes an electrician and the other a carpenter. They live until ripe old ages, ending up in the same nursing home and dying a few days apart from each other.

Now, one of these men was Nixon and the other was not. Which one? If we can't tell the difference then what sense does it make to claim such a thing?

It seems that for rigid designators to be viable then we have to establish essential properties for identification, yet what essential property could single out a particular person from a crowd?

I see no logical contradiction in the possibility of Nixon being born to different parents. For example, imagine a possible world exactly like this one except the only difference is that Nixon has a different mother. He's still the iconic 37th president, same physical appearances, same DNA, same life choices, etc., identical in every way except that his mother is a different woman. If, according to Kripke, that's not Nixon then I think he will have a hard time convincing Nixon of that fact.

Also, in the example I gave, it's not the problem that Nixon's parents are different, it's the problem of which twin Nixon is. We know it's supposed to be one of the twins but which and for what reason? It seems like there's some mysterious essence being posited.

But that would mean that Nixon would have a different genetic makeup than he actually had.

I stipulated that his DNA would be the same. Though of course it's highly unlikely, there is no logical contradiction in having different parents but winding up with the same DNA.

Also, even assuming different DNA, surely there is a possible world where Nixon is born with Down syndrome or has some other genetic abnormality that our Nixon doesn't have.

The example of a rigid designator most commonly offered is that of "Richard Nixon", which identifies a particular person. One descriptive phrase for the person "Richard Nixon" could be "the 37th President of the United States". However, there are possible worlds in which Nixon lost the election or died shortly after birth. In those possible worlds, "the 37th President of the United States" doesn't designate Nixon but some other person, e.g. Hubert Humphrey.

The claim made by Kripke and other proponents of rigid designators is that while the "37th President of the United States" only refers to Nixon in this possible world, the phrase "Richard Nixon" refers to Nixon in all possible worlds, even in worlds where Richard Nixon was assassinated as Vice President, died of pneumonia while serving in the senate, had a different name or was even born with some kind of congenital deformity making him unrecognizable to us.

My problem now is that I don't know how far to take this. At what point do I start identifying someone similar to Nixon as a different person instead of Nixon?

Imagine a possible world in which Nixon has an identical twin brother and are both given up for adoption. However, neither of them are named Richard and they both take on the surname of their adopted parents. One is Frank and the other is Fred. Neither of them enter politics. One becomes an electrician and the other a carpenter. They live until ripe old ages, ending up in the same nursing home and dying a few days apart from each other.

Now, one of these men was Nixon and the other was not. Which one? If we can't tell the difference then what sense does it make to claim such a thing?

Old topic, but I'm reading Naming and Necessity at the moment, so what the hell.



Having read the first lecture, Kripke's position on this seems to be that the problem of transworld identity (at least in this form) is based on a misguided view of possible worlds. You are thinking that when we make a statement like, "Richard Nixon might not have been President", we have to whip out our subjunctive telescope, look at all the possible worlds, find Richard Nixon in each of them, and then check whether or not he's President. However, Kripke says that possible worlds are stipulated, not discovered. Who, or what, is the statement, "Richard Nixon might have lost the 1968 election" about? Is it a statement about some possible Nixon in some possible world? That seems strange. Rather, the subject of the statement is the actual Nixon in our world, and surely it is true of the real Nixon that he might not have been president. As Kripke puts it, "We can point to the man, and ask what might have happened to him, had events been different." [Emphasis is Kripke's own]

Notice that you stipulated the Nixon-twin world, and, indeed, you stipulated that Nixon was in it. The problem here is epistemic rather than metaphysical. Certainly, it is possible that Richard Nixon might not have been called Richard, and there is no reason why he shouldn't have had a twin brother. Nor is there any reason why he couldn't have pursued a career other than politics; he might have even been a Democrat! However, you have said, "Nixon might have been born with a twin. The parents might have called the twins Fred and Frank. Which one is Nixon?" I only have enough information to say that I don't know, but one of them is Nixon.

Great response. I had thoughts along this line but then I had trouble seeing how this supports the idea of necessary a posteriori truths. Can you shed some light on the claim that it is a necessary a posteriori

The same goes for statements like Nixon might have been a goat. We certainly might discover that Nixon had been an elaborately disguised goat all along, but let's assume that's not true. Given that Nixon is a human, is it possible that he might have been a goat? I can't see it myself.

Doesn't it look as if when we come across a statement of possibility that Nixon might have been a goat, and it offends our intuition, we then just decide it is not a logical possibility, but rather rather merely an epistemic possibility. It is convenient, but, on what grounds do we decide this?

The principle that one object cannot itself be a different object, I would think. I think it's fair to say we have enough evidence to say that Nixon was, in fact, not a cleverly disguised swan, and that he was actually a human. Given that fact, we can still say that a swan might have beaten Humphrey in the 1968 Presidential Election, then beaten McGovern in 1972, resigning in 1974 after scandal; they may even call the swan 'Nixon'. What I don't think we can say is that this swan is the same object as Richard Nixon, instead, it is something different from Nixon that is being placed in similar situations.

Is there any way we might be able to say that the swan is Nixon? There's certainly a munitions factory worth of bullets one might bite on this topic. You might say that some freakish genetic mutation could take place in utero rendering Nixon a swan; although, that raises questions about the point at which Nixon can be said to come into existence. You might say that there is absolutely no problem with Nixon being born a swan, to swan parents, from a swan egg. How this wouldn't simply be a swan, I don't know. Alternatively, you might simply reject causal naming theories; though they seem the most plausible to me.

Is it a statement about some possible Nixon in some possible world? That seems strange. Rather, the subject of the statement is the actual Nixon in our world, and surely it is true of the real Nixon that he might not have been president. As Kripke puts it, "We can point to the man, and ask what might have happened to him, had events been different."

Yes, very puzzling. I think we need some deeper understanding of how metaphysical possibility is supposed to differ from logical possibility, since it is logically possible that Nixon was a swan (I suppose). Is there a deeper understanding of metaphysical possibility?

So, this is modal actualism rather than modal realism?

Presumably we would say it that it's not water, that is in fact something entirely different, just as if we brought a sample of liquid composed of XYZ back from a distant planet. Presumably, upon discovering it's molecular structure, we would not conclude that some water is not H2O, instead we would treat as we treat fool's gold: it isn't gold.

I can think of two objections.

1. If Nixon can have different properties in different worlds, being a president, being a janitor, etc, why can't water have different properties? Why call non-H2O water Fool's Water but not call non-presidential Nixon Fool's Nixon. In both cases something extremely central to our concepts is missing.

2. There is a lot more to the reason why we call pyrite Fool's Gold than its molecular composition. If pyrite had all the same physical properties as gold; ductile, malleable, conductive, etc, then I don't think it would be such a big difference.

So, it seems like I can imagine a possible world where Nixon isn't president and water isn't H2O. It seems like I could imagine a possible world with a beaker full of H2O but when apply a flame, it explodes instead of extinguishes. It seems like I could imagine a possible world with a beaker full of water but its molecules are made of XYZ.