Alvin Plantinga is widely regarded as one of the world’s leading Christian philosophers. Watch the video below and ask yourself, WTF?
So as not to spoil your fun, I’ll refrain from offering my take on the argument until readers have had a chance to comment.
So stop me if you’ve heard this one before, but consider this:
Suppose I am standing in a swamp during a lightening storm. I get hit by lightening and instantly decomposed into my constituent atoms. But by some even stranger fluke, in the next instance another bolt of lightening hits the swamp and a being is created with exactly the same atoms as me in the same configuration. (1) Is it still me?
What if we were in two separate swamps and the atoms themselves were different? The second swampman would be physically identical to me and so would have the same thoughts as me and seem the same person as me to my family. (2) Is he me?
(3) If it all comes down to the first me being hit by lightening, why is that?
(Of course, this scenario sounds completely ridiculous but it really is not that much different than a Star Trek transporter, which shows the power of mass media in shaping what is conceivable).
I know these are pretty basic philosophy 101 (or maybe 102) issues, but if you want to take the time to answer, that would be great.
My answer: 1. yes, 2. yes, 3: quantum entanglement of yes/no.
(just kidding on that last one).
The reasons for my answers come down to my various first post: Star Trek transporters seem logically consistent with preserving personal identity.
Except that Star Trek transporters are magic and do not and will not exist. If they did exist, they would kill the person being transported.
I think energy is part of a physicalist concept of the universe, but I don’t think it is scientifically meaningful to speak of an entity made of energy. As I understand it, energy is a property of something that already exists. But someone who knows more science than me can correct me if indeed it is possible to have entities made of energy.
But as said in other posts, I believe science has not ruled out the possibility that I can be re-implemented in any set of atoms with the right causal power. Or you could substitute the scientific concept of fields for atoms, I guess, since as I understand it, another way to look at it is that atoms are just particular states of quantum fields.
Yes. This exactly Keith. So given that I’ve killed many thousands of brain neurons (having been fond of a drink or two at one time or another) and yet still being “Robin” (as it were), what then is the minimum amount of brain in a particular arrangement that must exist for a “Robin” first-person perspective to come about again? Is it even possible?
Geez, you’re no fun at all.
I suppose you don’t accept the swampman example either, then?
But ccording to Leibniz`s principle if I can not make the same statement for C and D, C and D are not the same X.
This is a variation on my river and flame theme.
Dynamic objects are generalizations about their behavior. If you’ve had a relative develop dementia, you understand that your question is both real and without an absolute answer.
How could the probability of a state with you be zero? You are here, typing at me, so the probability that you exist must be > 0.
Also, I think that the finite number of configurations has to be taken into consideration too.
Unless I am a brain in a vat, in which case I don’t know if you exist in the physical sense I meant above. But I excluded that possibility in the first post.
Now I understand that you may not mean that specific, existing Keith S, but rather some general, not specific “you”. So let me be clear that by you I meant you. Or maybe ‘by “you” I meant you’ would better.
You know (so to speak), the above is weirdly reminiscent of that de re/de dicto stuff I am trying to understand when the intensional context is one of possible worlds. I probably need more sleep.
Robin,
I don’t think there’s a sharp line. It’s a matter of degree, like baldness.
If we start changing your brain, neuron by neuron, it will gradually become less Robin-like, but we won’t be able to point to a specific moment when the “Robin” perspective vanishes and a new one comes into existence.
Bruce,
I’m talking about the probability across the entire multiverse. If there are infinitely many universes, then identical copies of me can exist in a finite number of universes even though the overall probability is zero. “Finite number” includes “one”, so it is possible that there is only one copy of me, even if there are infinitely many universes.
An infinitude of universes is not enough to guarantee more than one copy of me. The sizes and configurations of the universes also matter.
keiths,
In your last couple of descriptions of Plantinga’s argument you slip from his de re premises to your own de dicto ones. He’s not talking about the names or the propositions, but the entities themselves–whatever one calls them. Thus, he would agree with Blas that you’re simply denying Leibniz’ Law there.
That is
X is such that I can conceive F of it.
Y is such that I cannot conceive F of it.
Therefore, X is not identical to Y
is valid precisely because it follows from Leibniz’ Law. You have to deny one of the premises if you’re not going to slide from those de re locutions to something like
I can conceive (the proposition) that X exists but I don’t.
I can’t conceive that I exist but I don’t
Therefore, I am not identical to X
That argument is indeed invalid for the reasons you mention in your more recent critique: they involve differing concepts. But Plantinga doesn’t make that invalid argument (which he’s well aware is invalid).
Mmm…an interesting issue I hadn’t considered. My father-in-law is succumbing to Alzheimer’s.
walto,
Plantinga thinks his argument is de re, but it’s actually de dicto.
Assume that C and D actually do refer to the same thing X, but that you don’t know this yet, so you apply Plantinga’s argument to find out.
If you can imagine something about C that you can’t imagine about D, then Plantinga’s argument will incorrectly tell you that C and D do not refer to the same thing.
C and D are different de dicto, but they still refer to the same thing X. Plantinga has mistaken a de dicto difference for a de re difference.
I think that’s probably true. My father-in-law has not just stopped being himself; there are days he’s “all there”. It’s a gradual shift away.
However, I do not think his first-person perspective has changed. That is, he’s still in there looking out of those eyes, it’s just that he no longer has much of a record of having seen the world he’s inhabiting.
Blas,
No, Leibniz’s principle says that if all of the properties of M and N are the same, then M and N are the same object.
Plantinga’s mistake is that he thinks that “I can conceive of X having property P” is itself a property of X. It’s not. It’s a property of Plantinga, not of X. Or more precisely, it’s a property of Plantinga’s concept of X, but it’s not a property of X itself.
SO Leibniz`s principle is wrong.
Sorry, I don’t follow you. Here is the model as I see it.
1. Finite number of outcomes. I am pretty sure this means that p=0 iff an event is impossible. I know that it is wrong to conclude that for for continuous sample spaces as you pointed out earlier. But I am pretty sure it is OK for finite sample spaces.
2. Independent, identically distributed trials. Independence from the inability for separate universes to communicate. Identical distributions from the fact that all the universes have exactly the same laws and constants.
3. This universe constitutes a sample of 1 from the above model.
Hence the probability of this universe occurring is some p> 0. Hence in an unbounded number of iid trials, it will occur an unbounded number of times.
(I think this falls out of weak law of large numbers where we take a binomial distribution over p and let number of trials go to infinity. For n trials, the theoretical mean number of occurrences of our universe is np. As n goes to infinity, the sample mean number of occurences over all n universes goes to the theoretical population mean, np, which goes to infinity too. Now it has been many, many years since I studied that type of thing, so I took a bit of a flyer on that. I could be way off.)
I have to admit, I may be wrong on the supposition that, for finite sample spaces, only impossible outcomes have probability 0. So if you are thinking that is where I am wrong, can you describe how that can happen?
Bruce,
What do you mean by “finite number of outcomes”? Are you talking about the number of possible states within a universe? Or the number of possible universe “types”?
I mean the number of possible states that a universe could take Further, the same possible set of states applies for all universes with the same laws and constants.
Blas,
No. See this comment.
Isn’t Plantinga actually using the inverse of this statement? (If I can rely on wikipedia, I guess your statement and its converse are both called Leibniz’ Law, confusingly).
Ok, then you were wrong agreen with this because you are now saying that the “properties” of both should be identical not the possible statements.
Bruce,
I question this assumption. Two universes can presumably share the same laws and constants without starting in the same initial state, so I don’t think you can assume the same distribution of possible states.
I generally agree with what you’re getting at here, but, as you put it here, I don’t think it’s entirely fair to Plantinga. It amounts to the claim that one simply cannot make de re references to objects (I mean, anything can be renamed in such a way that the person in question doesn’t know both names.). Plantinga simply disagrees with that claim, and, obviously, his argument requires that one CAN make de re references to selves in a way that you here deny. Another way of putting this is that when you make “C” and “D” unknown by the arguer to be names of the same thing, what you’re doing is supplying opacity–i.e., making the argument de dicto. The morning star is such that John doesn’t believe it is the evening star–but that means that the evening star is also such that John doesn’t believe IT is the evening star. That’s how de re reference works.
So, again, I don’t think there’s anything invalid about his argument. The argument is bad because one of the premises is false. (It may not be QUITE as lame as you think, however.)
Blas,
keiths:
Blas:
Look again at what you wrote:
I agree with that, but not with this:
When Plantinga says “I can conceive of X being separate from Y”, that is a true statement about Plantinga (or Plantinga’s concept of X, not about X itself.
The properties of X remain the same whether Plantinga or anyone else correctly or incorrectly conceives of X.
socle,
It’s an “if and only if” relationship, so it works both ways.
M and N are identical if they share all their properties, and they share all their properites if they’re identical.
I think if there are only a finite number of initial conditions and again these were iid then the general point of an infinite number of you’s would still follow.
But I don’t remember that point being discussed in the popularizations I’ve read, so I have no idea if it is part of the speculation which leads to infinite you’s (which seems to be fairly “common”).
walto,
It’s not that we can’t make de re references. It’s that when Plantinga says “I can conceive of X having property P”, he is really saying “my mind can form the concept “X has property P”.
It’s a statement about Plantinga’s mind and his concept of X, not about the real X.
There is a big difference between saying “X is round” and “I can conceive of X being round”.
I’m referring to an argument about minds existing without any body whatsoever. Is that “the argument” you mean too?
Do you think P would say “I can conceive of a physicalist universe where minds have no bodies”? That is the statement I have trouble with.
I guess it comes down my definition that anything physical counts as a potential body. That seems to make the argument pointless if it is trying to separate minds from _any_ body whatsoever. Pointless in the sense that your answer to what is conceivable already includes whether dualism is part of you are conceiving.
Or pointless if you are trying to prove physicalism is false (which I don’t seem him doing explicitly in that video, BTW, but may be where he wants to go).
But that it is not a Leibniz`s requirement for his principle. His expression is
“entities x and y are identical if every predicate possessed by x is also possessed by y and vice versa”
Every predicate should be possible to share between them also the wrongs predicates.
Sorry, can’t get the concept. There’s stuff. It’s real stuff or it’s imaginary stuff. Maybe there’s complex stuff. At some point imaginary stuff interacts with reality and its effects are detectable or it doesn’t and remains imaginary.
Impossible to self-judge. My Mum suffered from Alzheimers in the last couple of years before she died but she was still herself in so many ways; just a little diminished.
Yes indeed. Whilst math concepts are useful models, the real world does not consist of things with tidy edges.
Here is a different kind of dualism that makes a bit more sense to me.
In the 1920s, physicists had no idea that nuclear properties like “color” (for quarks) existed (I won’t go so far as to say they could not conceive of these properties, however).
But now we know these properties exist.
Now we cannot currently understand how first person experience can arise from physical things. Maybe this means that beings have first person experience because there are “mental” properties which are not yet known by our physical science and which cannot be accessed by our current conception of science.
That is a form of property dualism, I believe.
It is not that there is a totally different kind of stuff, but that (some) stuff has properties which are totally outside current science and so outside the current conception of physicalism.
I’m impressed by how you go toe-to-toe with walto in tossing around the de re/de dicto terminology.
Did you study philosophy formally?
Or is it just something you picked up posting at UD, for example?
Although it was not my original source, I had Tegmark’s Mathematical Universe handy. I checked and he makes the same prediction that an infinite number of you’s is a consequence of inflation as it is now understood. A little googling yields The Multiverse Hierarchy. From intro there (I have not read whole paper yet):
Bruce,
Those Hubble volumes are all part of our universe. They overlap each other and share the same spacetime.
That’s why I said that
Bruce,
I learned those terms yesterday, so I’m sort of winging it. I’m glad to hear that I sound convincing, though! 🙂
And although the terminology is new to me, I’ve thought about the distinction itself quite a bit, because it pops up in lots of philosophical contexts.
As a fellow computer person, you may appreciate this: de re/de dicto is analogous in a lot of ways to the structure/pointer distinction.
No, but I think about philosphical questions a lot, so the concepts are often pretty familiar even when the terminology isn’t. It’s fun to encounter something like the de re/de dicto terminology and realize “Ah, so that’s what the professionals call it!”
OK, then if that is how think of the word “universes”, then there are an infinite number of hubble volumes in our universe and an infinite number of you’s among them.
Same concept in different words as far as I can see.
(FWIW, as I read him Tedmark calls this the level I multiverse and calls it different level I parallel universes (with an s). But he does point out that other define universe differently.)
Alan,
The question is whether the “real vs. imaginary” dichotomy lines up with the “physical vs. non-physical” one. It’s at least conceivable that they don’t,
though I strongly suspect that they do.
Hey, not only a quick study, but with the gonads to do the first public airing
with a tough audience. Even more impressive!
Let me see if I follow your structure pointer analogy. Consider
Superman might not have been Clark Kent.
If I understand the concepts, the de dicto reading is that Superman might have chosen a different secret identity and so on that reading it is possibly true.
That would be the pointer case: a pointer embedded in the instance of the superhero class representing superman might have been set to point to a different secret identity.
The de re reading would be that since Superman and Clark Kent are the same person, the sentence is false.
That would correspond to a the superman object being defined with two name fields and once set up, unchangeable.
The modal version of de re/de dicto is the one I find most confusing, and on top of that iI am sure I understand your analogy, so that could be off base in two different ways.
But it is the best I could could up with this late at night.
Blas,
Here’s a thought experiment that may help.
Imagine that your friend Luca has been living in the jungle for 15 years, out of contact with the outside world. You meet him immediately after he comes out of the jungle, before he has a chance to catch up on the news he has missed.
You are discussing politics, and you ask Luca “Do you think it’s possible that the president of the United States is white?” Luca gives you a funny look and says, “Sure, it’s possible. In fact, it’s almost certain that the president is not only white but male.”
Later, you show Luca a photo of Barack Obama playing basketball with his friends. You ask Luca, “Is it possible that this man is white?” Luca examines the photo and says “No, this man is clearly black.”
So Luca says it’s possible that the president of the US is white, but he thinks it’s impossible that Barack Obama is white. If he were foolish enough to use Plantinga’s logic, he would say to himself: “The president of the US has the property of ‘possibly being white’. Barack Obama does not have that property. Therefore Barack Obama is not the president of the United States.”
That’s a good example, keiths. However, some would say that Barack Obama does in fact have the property of ‘possibly being white’ since his mother was white. 🙂
socle,
You obviously don’t know the “one drop rule“. This is Murrika we’re talkin’ ’bout. 🙂
Bruce,
Yes — but only if the universe is open (infinite), the favored inflationary model is true, and the universe is ergodic.
Again, my point is that
Bruce:
Not really. There’s a big conceptual difference between multiple copies of you in the same universe versus copies of you in different universes throughout the multiverse..
He does, but he’s sacrificing accuracy for the sake of convenience and brevity. It’s easier to talk about a “multiverse hierarchy” than it is to talk about a multiverse/Hubble-volumes-inside-a-universe hierarchy.
The Hubble volumes really are quite different from genuine separate universes because they share the same spacetime and they overlap with each other. In fact, there is a Hubble volume centered at every point in the universe, and each one overlaps with zillions of others.
So… Plantinga is respected in the community of philosophers, not because the arguments he comes up with are any damn good, but, rather, because he does such an effective job of obfuscating the Bullshit Nature of his arguments?
Wow.
That’s a pretty damn scathing indictment of the entire field of philosophy, IMAO (in my arrogant opinion).
As best I can tell, Plantinga’s schtick boils down to Imagination = Reality. Since this is bullshit, I see no reason to give two wet farts in a hurricane about any of Plantinga’s verbiage.
You’re in the ballpark, but a little bit in the bleachers I think (though I may be mistaken)..
The key is to remember that de re references are to the items, and de dicto references are to the propositions or statements. So with de re necessity, you things like
Necessarily, the man who went to dinner went to dinner.
Note here, we’re not talking about the SENTENCE, because in some possible world those words could mean that Alvarro just farted. But, given what those words mean in English, you get a necessary truth. Same for the proposition that the guy named “Clark Kent” is named Clark Kent. These are necessary rather than contingent because we aren’t talking about the individuals there, but the propositions. If we shift our focus to the entities, this changes. For example, this is false
The x such that x is named “Clark Kent” is necessarily named “Clark Kent” (i.e., he couldn’t have been named anything else).
That seems false. It seems like the Kents could have named Superman “Basil” if they’d felt like it, that there’s a possible world in which Superman’s secret identity is “Basil Kent.” So one way of seeing this difference is to move the modal operator–this case “necessarily”–inside the scope of the quantifier (“The x such that”). Putting it back outside–where the necessarily applies to the whole proposition, you get a necessary truth:
Necessarily, the guy named “Clark Kent” is named “Clark Kent.”
That’s de dicto.
There’s a great early paper by Plantinga on this stuff– “De Dicto et De Re”, and Kripke’s _Naming and Necessity_ covers a lot of that ground too.
What Kripke and Plantinga focus on is their (fairly intuitive) view whatever this or that thing might have been or done (Lincoln might not have been President, Napoleon might have been a popular flautist) they could NOT have failed to be self-identical. So
Clark Kent was necessarily Clark Kent
Clark Kent was necessarily Superman
are both true de re, even though if you put them in de dicto form only the first one produces a necessary truth.
I can’t comment on the structure/pointer analogy, because I don’t know what those are. Hope this helps.
Looking at my last post again I see that, besides the typos and missing quotation marks which it’s too late to fix, sticking with Superman as an example was probably a mistake. Fictional “entities” are tricky and I don’t know if de re reference is even possible with respect to “them.” I mean, COULD Superman have been called “Basil Kent” in some possible world and still have been Superman (i.e., that same DC Comic superhero)? I don’t know.
Anyhow, it’s clearly better to stick to actual things when talking about de re reference. Cicero, Tully, Venus (the Planet, not the god), etc. Sorry if I only confused things more!
BTW, just saw this http://www.spiritscienceandmetaphysics.com/scientists-claim-that-quantum-theory-proves-consciousness-moves-to-another-universe-at-death/ posted at another site. It seemed to me connected to what a lot of y’all are writing about on this thread.
But if it’s not–or this seems like a thread hijack–I apologize in advance.
Thanks very much for taking the time to provide this mini-tutorial (and to extend the baseball metaphor!). I really appreciate it when you and KN do this type of thing; I hope that you two as well get some benefits, possibly by honing your skills in explaining these concepts to undergrads.
I did find the Plantinga paper (it’s the 1969 with the shout-out to Aristotle, at the start, I assume). But it rapidly becomes very tough going for a novice like me.
I have found that the critical mass of basic knowledge I need to understand the primary literature on Phil of Language is much higher than for Phil of Mind. Even though I am (or at least was) very comfortable with the abstractions and formality of (undergrad) math, I find the Phil of language stuff a tough slog.
I think part of the reason is that that this abstraction is often expressed in English rather than a formal notation. Or sometimes it is expressed in both English and formal logic notation. But then that double expression gives me three problems:
– what does the English mean
– what does the formal logic mean
– how is it that they are saying the same thing.
Anyway, thanks again, I will definitely spend time puzzling through what you have posted.
(Aside: the Cicero/Tully different-name-for-same-guy example definitely needed a googling the first time I came across it. I wonder how many of current undergrads have the background that the original audience must have had to make this seem a helpful example to whoever created it).