Thomas Metcalf

I agree with what you wrote in the rest of the post, but I have a question to ask here. I'm pretty sure you'd only have to show that for every V there is a y in V s/t all essential properties that hold for x in U also hold for y in V. Counterparts might have some different accidental properties, right?

I think it is indeed important to distinguish what kind of possibility we mean. As I see it, there are really three kinds. Logical possibility is non-self-contradictoriness, physical possibility is "happens somewhere in the universe," and nomological possibility is "observed somewhere in the universe." Is that accurate? I have a feeling it might be oversimplified.

[ July 31, 2002: Message edited by: Thomas Metcalf ]</p>

Philip Osborne

"On what are you basing this judgement? Why is the possibility of having necessity entity selective, and why some entities and not others? Of course I deny that a necessary dog exists in any possible world (and thus is...."

A judgement about a thing's modal status is not merely property we can arbitrarily ascribe to anything and expect to come out with a meaningful concept. For instance, we cannot indiscriminantly ascribe "possible existence" to a square circle, because the properties of a circle are such as to make the thing impossible. In some sense, the modal status of a being can be thought of as "supervenient" on its other properties. And clearly, the properties of a dog entail contingency. If the necessary dog is to be a dog, it must share some similar properties with dogs we observe in everyday experience. These properties are inextricably contingent, meaning the necessary dog will be both contingent and non-contingent. If the necessary dog does not share such properties, it is obviously not a dog.

"Expanding that, it becomes []p =&gt; [][]p, or []p =&gt; []p. So what?"

Most analytic philosophers would tell you that if something is necessary, every true proposition necessitates it. Thus, if Lp =&gt; p were true, then p would be an actual fact. Since Lp is necessarily true, it follows that every fact necessitates it. Since p is a fact, p necessitates Lp. Note that we can only reach this conclusion if we know that the conditional is true (it may or may not be; to my knowledge, modal logic is not truth-functional). Since L(p =&gt; Lp) and L(Lp =&gt; p) are both true, there is no asymmetry in these instances of necessitation.

Another problem is that your example involves propositions, and propositions do not stand in causal relations to each other, by any definition of causation. Thus, your example would be excluded at the beginning.

"Please give me a reason."

For the same reason that there can be no greatest prime number. For any amount of greatness a world could contain, there is a world that contains more than it. For instance, take Gaunilo's Lost Island. If I think that having fruit is a great-making property for an island, then the greatest conceivable island has no instrinsic maximum, because for any possible amount of fruit in the island, there is always an amount that is greater than it.

"What does this have to do with creating-then-destroying universes infinitely?"

I misread your objection before, but it seems that destroying a universe right after its creation defeats the purpose of creation. God would be destroying universes constantly in order to reach a goal that could never be reached.

"If say, an incredibly evil world was the only logically possible one God could create, would he see fit to create it, or would he just remain inactive? Since...."

Yes, God probably would not create a world of pure moral and natural evil. But so what? Why does this make it unacceptable for God to create a world that does not contain such evils, even if this world was not perfect.

"To claim that x is a necessary being, you would have to show that for every V there is a y in V such that all properties which hold for x in U also hold for y in V."

Thomas is right; you've ignored the distinction between essential and accidental properties. If you ignore this distinction, the results will be highly counterintuitive. For instance, it is intuitively plausible that I am the same person I was when I got up this morning. But I do not have all and only the same properties that the person getting up in the morning did. For instance, my morning counterpart had the property, "making the bed" while I lack that property, and I have the properties, "has already taken a shower today" and "typing a message in the II forum right now," which my counterpart lacks. According to your analysis, I must give up my assumption that I am the same person I was this morning. Once we countenance the essential/non-essential distinction, we see that there is no contradiction in affirming that a necessary being has contingent properties, provided they are non-essential.

"What does "possible" mean in this context ? Logically possible (i.e. not self-contradictory) ? Physically possible?"

It should be noted that thought the greatest prime number is conceivable, it is not logically possible. Nonetheless, I am going to take "possibility" to mean metaphysical possibility, which can be considered the most primitive form of possibility there is.

This post was a little rushed, so there may be sloppiness and errors.

Sincerely,

Philip

[ July 31, 2002: Message edited by: Philip Osborne ]</p>

HRG

If not all properties of x are held by y in V, I don't think we could call y "the same" as x. A close cousin, at best

FWIW, I don't believe that we can actually separate essential from non-essential properties in a non-arbitrary, objective way.
Could you explain what you mean by "nomological possibility" ?

I probably should say that my views about the whole necessity stuff are influenced by Gödel's Completeness theorem (which says something like that those propositions which are valid in all universes - aka tautologies - are exactly those which are provable in predicate calculus).

Regards,
HRG.

HRG

[quote]Originally posted by Philip Osborne:

"To claim that x is a necessary being, you would have to show that for every V there is a y in V such that all properties which hold for x in U also hold for y in V."

Thomas is right; you've ignored the distinction between essential and accidental properties. If you ignore this distinction, the results will be highly counterintuitive. For instance, it is intuitively plausible that I am the same person I was when I got up this morning. But I do not have all and only the same properties that the person getting up in the morning did. For instance, my morning counterpart had the property, "making the bed" while I lack that property, and I have the properties, "has already taken a shower today" and "typing a message in the II forum right now," which my counterpart lacks.
[quote]
This is because "today" is not an invariant concept. If you formulate your properties as "making the bed at 9:00 AM, July 31st" etc., the problem disappears.
Not if you formulate your properties in a "time-absolute" way.
But what is the criterion to distinguish between those categories.

I see a circularity arising between:
"Essential properties of X are exactly those which must continue to hold if X is to staý the same" - and
"X has stayed the same if all essential properties of X still hold".
Please delineate your concept of "metaphysical possibility.

Regards,
HRG.

"Philosophy is the systematic abuse of a terminology which was created for that very purpose" (ascribed to Wolfgang Pauli).

Thomas Metcalf

As Phillip Osborne pointed out, if we don't allow beings with differing accidental properties to be "the same," it's harder for us to account for such things as identity. I think we should adopt the distinction, at least for practical reasons, because it makes identity so much easier.

This is how I distinguish accidental and essential properties: An essential property is a property that, if X loses it, we can no longer call the being in question X. However we define X, those things we mention are its essential properties.

Nomological impossibility is impossible according to the laws of nature. This is closely related to physical possibility. Phenomenon P is nomologically impossible if we have never observed it happening. P is physically impossible if it never happens. As I see it, we can never really know whether something is physically impossible, except that all logically impossible phenomena are physically impossible. Does this seem clear and coherent?

[ August 01, 2002: Message edited by: Thomas Metcalf ]</p>

Thomas Metcalf

In my experience, metaphysical possibility is the same as logical possibility. Is there a difference in your view? (To me, a logically possible world is a consistent and maximal proposition.)

Philip Osborne

Your "time-absolute" solution to the problem would seem to be unacceptable to an empiricist such as yourself. The reason is that it supposes realism about the future; it must assume that the future does, in fact, exist, even though it hasn't happened yet. If the future did not exist, I would not have had the property "took a bath at 6:15 a.m." while I was making the bed at six, thus running into the problems I posed before. But it does not seem to me that realism about the future is acceptable for the empiricist, since it has not been experienced. I could be wrong, but on this analysis there seems an inconsistency in your position.

I will take "metaphysical" possibility to be the kind of possibility which is signified by "L" and "M." It seems generally acceptable to treat consistent and "maximal" propositions as being possible in this sense, although the point I wanted to make with the greatest prime number example is that not all things consistent (non-self-contradictory) are logically or metaphysically possible. However, there is another sense of "consistent" which means "possibly exemplified." Of course, this is not very useful in explicating possibility.

Sincerely,

Philip

[ August 01, 2002: Message edited by: Philip Osborne ]

[ August 01, 2002: Message edited by: Philip Osborne ]</p>

HRG

And we can call the being in question X if it still has all the essential properties of X ....

Forgive me if I smell circularity

But in general we can make up many different definitions of X.
For instance, I could be defined as the European human being who participates in this thread and whose first name is "Hans", since there is no other entity which fulfills those conditions. Of course, I could be defined in many other ways, too.

Apparently, my essential properties vary with the definition which was chosen.

Regards,
HRG.