And the conclusion: that S is 1 metre long is an a priori, contingent truth. — Banno

Feeding this back into what has gone before, it is possible that Nixon was called Nixoff, and was a native of Canada and became a social worker. At which point, there is only the stipulation of the possible world that makes Nixon and Nixoff 'the same person'. (Which could be made more plausible if we suppose that his parents (possibly) emigrated and changed their name.)

But such stipulations are susceptible to ridicule or earnest criticism, though they be immune from dis-proof. Just as a stipulated metre stick can be criticised as being prone to expansion when damp or hot, so Nixoff can be criticised as being uninterestingly Nixon. Or, a possible Moses who didn't part the Red Sea, as not the Moses that anyone cares about, or a possible world in which the moon landings were faked, as too fanciful.

But possible worlds have uses, (unlike the counterfactuals being considered here), like metre sticks, either as projections to the future - I might go shopping later, it might stop raining: - or as tools of discovery of the past. The detective considers possible worlds in which each of his suspects committed the murder, works out the consequences in each case, and looks for evidence that supports or contradicts each possibility. Could Armstrong have done it and faked his alibi of being on the moon? could Nixon have done it and not talked about it on his tapes? Could Moses have time travelled? Possibilities are eliminated until the only one left is that the butler did it. And time will tell whether or not it stops raining and I go shopping.

In practical modal reasoning, there is a rule against changing the known facts, that there was a murder, that it is raining, That Nixon was the president, or whatever, that does not apply when one makes a novel about if Hitler had won the war. Such a novel can be instructive as a warning but is not admissible in court.

We have contradictory customs. — frank

We write novels, and we try cases, and different rules apply, but as long as we keep our customs separate, and keep fiction out of the courtroom, there is no contradiction.

We write novels, and we try cases, and different rules apply, but as long as we keep our customs separate, and keep fiction out of the courtroom, there is no contradiction. — unenlightened

Right. There's a TV show called The Man in the High Castle in which an alternate reality is depicted. It shows the allies having lost WW2 and North America is divided between the Germans and the Japanese. If we stop the think about it, it's amazing how easily we navigate a story of that kind.

We see Hitler, but we know it's not our Hitler. The two Hitlers are like cousins.

Yeah, that's the Phillip K Dick novel. I was thinking of Len Deighton's SS-GB, but there are others too. Unless we are philosophers, there is little problem understanding counterfactual possible worlds and their difference from the detective's possible solutions.

But as I have never been to the US, it is possible that The Man in the High Castle is substantially true, and all this stuff about presidents is fake news. Or is it?

Can anyone provide an example of a possible world or counterfactual situation that is not stipulated?

Can anyone provide an example of a possible world or counterfactual situation that is not stipulated? — Banno

Not me, but suppose that I could ...

{insert un-stipulated possible world example here}

... if I stipulate that a possible world is un-stipulated, is it stipulated? Does Kripke die of shame at this point?

No more than if you stipulated that 2+2=5

if you stipulated that 2+2=5 — Banno

I can propose a couple of possible worlds: (a) a dull world where the number signs have gotten swapped, or (b) a rather confusing one where Nature abhors a foursome, such that whenever one has two pairs of shoes, another shoe comes spontaneously into existence, and whenever two couples meet for lunch a child is born.

But what I was wondering is why you were asking anyone to stipulate an un-stipulated possibility? Architects' plans stipulate possible buildings; but just because they cannot plan an unplanned building, does not prove that unplanned buildings cannot exist.

So what's the problem?

Here's how I read it. Some folk say that there is a problem in identifying individuals in other possible worlds. Kripke points out that other possible worlds are specified by our musings... and hence that there is no problem with such a grand title as "transworld identification". — Banno

I don't see any problems, I am just interested in the 'identity criteria' to which Kripke refers to. What is it?

What is it? — Wallows

What do you think it is?

That doesn't work.

Can anyone provide an example of a possible world or counterfactual situation that is not stipulated?
— Banno

Not me... — unenlightened

Does that work better?

What do you think it is? — Banno

No idea, honestly.

Much.

Fine.

Perhaps we should move on. What do you suggest we focus on next since I got hung up on criteria for identity.

Heraclitus: "Can't step in the same river twice."
Frank: "Wow! It's the same river, but it changes over time."
Banno: "That's fine. It's the same river because we say it's the same river."

Heraclitus and Frank: :meh: :smirk:

Frank: "If I said penguins fly, would they? We say it's the same river because it's the same river, not the other way around."

Banno: "You're all idiots. Go back to work."

Frank and Heraclitus: :up: :up:

But as I have never been to the US, it is possible that The Man in the High Castle is substantially true, and all this stuff about presidents is fake news. Or is it? — unenlightened

Could be. Sometimes the fascism leaks out around the edges. :worry:

What?

You're all idiots. Go back to work.

:lol:

I doesn't work.

as you are the chap who made the funniest retort in web history, I forgive you.

If we're just saying that in counterfactual (or "possible worlds") talk, we can refer to things so that they're "the same x" as they are in the actual world, barring counterfactual modifications we make to them, and to some extent that's necessary to make sense of counterfactual talk at all, that shouldn't take a whole book/series of lectures to note. — Terrapin Station

It shouldn't, no. But David Lewis remained puzzled, I think, to the day he died.

Perhaps we should move on. — Wallows

I'm not sure there is any point. @Frank hasn't worked out that we can't step in the same river even once, and yet it is the same river. You say you haven't understood the notion of identity criterion, on the rejection of which the remainder of the book is based, and although I found it interesting to revisit, I have several other books I ought be reading.

You say you haven't understood the notion of identity criterion, on the rejection of which the remainder of the book is based, and although I found it interesting to revisit, I have several other books I ought be reading. — Banno

That's true; but, I'm willing to learn what it's all about.

Thanks.

But all you do is push stuff off the table. If you will not engage, I can't see how this will be any fun.

Where did Frank go astray?

But all you do is push stuff off the table. If you will not engage, I can't see how this will be any fun. — Banno

Where do you want me to look at?

I'm looking at this from page 53:

So : the question of transworld identification makes some sense, in terms of asking about the identity of an object via questions about its component parts. But these parts are not qualities, and it is not an object resembling the given one which is in question. Theorists have often said that we identify objects across possible worlds as objects resembling the given one in the most important respects. On the contrary, Nixon, had he decided to act otherwise, might have avoided politics like the plague, though privately harboring radical opinions. Most important, even when we can replace questions about an object by questions about its parts, we need not do so. We can refer to the object and ask what might have happened to it. So, we do not begin with worlds (which are supposed somehow to be real, and whose qualities, but not whose objects, are perceptible to us), and then ask about criteria of transworld identification; on the contrary, we begin with the objects, which we have, and can identify, in the actual world. We can then ask whether certain things might have been true of the objects. — Kripke pg. 53

SO what do you make of this:

When we think of Nixon losing an election, we must be thinking of a Nixon who ran in the first place, as opposed to a NIxon who left the US to become a Tibetan monk when he was 17. This possible world must also be one in which the sun didn't go supernova 10,000 years ago.

The list of things that had to be just so for there to be a Nixon who ran for president of the USA would appear to be massive and extending backward to the beginning of the universe. Therefore, I agree it's a simple stipulation.I don't agree that any of the profound philosophical questions associated with the stipulation have been answered by Kripke. — frank

Kripke has not rid us of problems associated with transworld identity, for as your quote shows there may be issues with regard to what constitutes an individual. Is Frank addressing the same thing?

I don't think so.

Is Frank addressing the same thing? — Banno

I don't think so also. I think frank is addressing a possible world in which Nixon could have chosen a different path than politics. What instantiates his identity is a world where his identity as a politician is found in, is our own world. I can't see above the horizons of our own world, so I'll leave it at that.