I was very skeptical about Mongrel's representation of Leibniz' concept of free will. It really didn't seem reasonable to me, that a man of Leibniz' calibre would define free will in this way. — Metaphysician Undercover

Me too. It resulted from the fact that his central theses clearly ruled out free will. Unlike Spinoza, he wasn't prepared to abandon freedom because of the place it occupies in morality. He played around with backing off of this being the best of all possible worlds, but that notion was designed to save God's character from the problem of evil.

I'm not thrilled by philosophers who start with a conclusion and then seek to built an argument to meet it. Maybe it's my Anglo-Sax cultural bias.

Oh good. Thanks!

Laws can't be derived logically from mere sets of empirical observations. — Pierre-Normand

That is correct.

The law would derive from some features of the nature of ravens — Pierre-Normande

To be precise, statements of natural law concerning ravens ideally express the nature of ravens. Expressions of that kind assert what one should expect regarding ravens, so there's a normative aspect to it. At the very least this is rooted in the normativity inherent in language use. Whatever more one says about it will reveal something about how one approaches the problem of induction. It's possible that some ontological commitment will fall out of that.. or not. It depends on the theory of truth in play.

Those contingent circumstances, as well as the contingent circumstances of the past evolution of this life form, would explain this biological law. This would be an example of a contingent biological law about ravens. — Pierre

Sure. It may be that the universe is necessarily the way it is. No apriori nor aposteriori knowledge contradicts this. So it may be that all true statements about the universe are necessarily true. Note that this would still be so if there actually is no such thing as natural law.

If, on the other hand, it follows from some set of laws of physics that Sue -- a mature rational human being -- must do A in situation C, then, if Sue additionally had some intelligible reason to do A, it is usually as a result of Sue's exercise of her rational powers of practical deliberation that she found herself in a situation C such that the laws of physics ensure that she would decide to do A. — Pierre

Sue was born and continues to live with hunger and needs of various kinds. These facts account for most of Sue's whereabouts and situational posturing. Whether her deliberation has any bearing on her location is broadly speaking the very issue under discussion.

That was a bit of a shorthand but I thought the context made it clear what I meant. If A depends conditionally on B, and B is contingent, — Pierre-Normand

If B (a set of spaciotemporal specifications), then A (where A is a statement of natural law.)

I don't think it's presently clear what it means for B to be contingent (in some way beyond the meaning that we can imagine things being different.) Maybe the universe is like a branching shrub and every possibility is manifest somewhere, sometime. Maybe the Eternal Return is a reality, but there's always room for slight differences. Is there some formalization of physical possibility that really helps make a case for volition?

Suppose you heard Banno was run over by a train and that he was definitely not ok, what would you then do other than just sort of knowing it? Give me your best showing of concern.

Here's mine: Did you hear about Banno and the train? Sucks, no? — Hanover

I would start collecting funds for a Banno Memorial... maybe similar to the Ground Zero thing in NYC. Or maybe like the Oklahoma City Federal Building Bombing Memorial... it was a bunch of twigs stuck in a fence.

I actually would like to know that he's ok. Thanks for the impression. Do you do Trump?

Look back at what you wrote... confusing the concepts of conditional and contingent. You know better than that. You also know that modal logic isn't going to help provide any foundation for the concept of volition. It's an analytical tool, not an ontological theory.

You really don't have to go past Searle's argument for volition. Extend your index finger. Wiggle it around. QED.

It looks to me like you've built an edifice of complete absurdity.

Banno.

Some natural laws of insular ecology apply only to island ecosystems and some natural laws of chemistry apply only to aqueous solutions in thermodynamic equilibrium. — Pierre-Normand

The concept of natural law isn't without its critics. Having to point out when and where a rule applies isn't much of a threat, is it?

The concept of a physical law being valid only if it has the form of a true unrestricted universally quantified statement is questionable. — Pierre-Normand

Obviously what happens in a black hole stays in a black hole. We were talking about whether the whole universe could have been different.

It is a concept that sneaks in contentious reductionist assumptions regarding material constitution. — Pierre-Normand

Reductionists are always sneaky... like Communists and the Devil.

Not quite the same. The necessity of identity is metaphysical, it is neither logical nor physical. — Pierre-Normand

I was talking about intensional vs extensional definition.

No, its not a matter of faith since even if one were agnostic regarding the sort of necessity that attaches to physical laws, and even if those laws were deterministic, compatibilists would not be worried about it. Conversely, hard determinists would deem us to be unfree even if the laws of physics were contingent. The impossibility for one not to be constrained by the laws of physics, and/or by the past state of the universe, are irrelevant to the existence of compatibilist free will or to the hard determinist's denial of the existence of free will. — Pierre-Normand

Good lord. Walked all the way to the top just to fall straight back down.

In that case, the concepts of logical possibility and physical possibility would be co-extensive. — Pierre-Normand

Maybe a Hesperus/Phosphorus type of difference. Anyway, for the discerning eye, we just affirmed that the answer to the title of the thread is:

YES.

Only in the case where it could not logically have been any other way than the way it actually is do the concepts of logical and physical necessity collapse into one. — Pierre-Normand

I don't think so. Suppose some new discovery reveals to us that the universe couldn't have been any other way (no specifics required... all we need is that such a thing is conceivable.) We'll call it the GNSD (great new scientific discovery.)

If it's true that the universe couldn't have been any other way, then laws of physics are necessarily true statements (though we may not have previously known that.)

So while we didn't know it, we said that logical possibility outstrips physical possibility. Post-GNSD, we realize we were always wrong about that. When we imagined gravity causing things to repel one another rather than attract, we didn't realize that this would conflict with a necessarily true statement and therefore, it's not logically possible.

Problem?

You haven't given any indication as to why you think the world could not logically have been different than it actually is. — Pierre-Normand

No. I haven't. What I note is that your argument starts with a hidden premise:

The universe could have been some other way.

You attempt at demonstrating that physical and logical necessity are co-extensive relies on your using "necessarily" equivocally as if there were just one kind of necessity. This is question begging. Of course if you assume that the world can't logically be any other way than (actual) physical laws dictate it to be, then those two sorts of necessity collapse into one. — Pierre-Normand

I asked you for an argument. Why are you saying that I was attempting to demonstrate something?

Your argument has as a premise that the universe could have been some other way. Why should I believe that? What do you know about the natural history of the universe that no physicist currently does?

As a matter of fact, it can be shown that "physical possibility" is an infinitessimal fraction of "logical possibility", so they are not the same thing. — tom

Cool. How is that shown?

You had issued a challenge for me to show "what properties physical possibilities have that logical possibilities don't or vice versa." I was merely responding to this challenge. It may not be physically possible for you to jump 10 feet high right now, but unless the physical laws that account for you not having this ability can be derived from logical laws, and hence aren't contingent, then it is logically possible that you would do so. — Pierre-Normand

If physical law is necessary, then the set of all physical possibilities is the same as the set of all logical possibilities. Right?

Drop the issue of entailment. It's irrelevant. All that's required for statements of physical law to be necessarily true is that it's true that the universe couldn't have been any other way.

You have offered no reason to think that the laws of physics are logically necessary. — Pierre-Normand

So what are we talking about now? I edited my previous post. Note that I mentioned we can discuss Leibniz further in another thread if you like.

When a photon travels towards a double-slit, is it logically possible that it goes through both slits? — tom

If an electron is a wave, yes.

The invitation was more to make the term "physical possibility" meaningful by offering a persuasive reason to believe there is such a thing. It looked to me that previously all that was offered was that "this is the way it's normally thought...."

So if physical law is necessary, then the set of physical possibilities has the same members as the set of logical possibilities.

Leibniz knew his CIC (which you mentioned earlier) threatened the existence of free-will. We know this because he explicitly described the problem. He came up with a number of methods for rescuing free will without abandoning his central philosophy. If you'd like to discuss those methods and how one of them might amount to basing free will on what we call logical possibility, you can start a thread on it and I'll join you in the discussion. You probably already noticed that the SEP isn't sufficient for getting the whole picture on Leibniz. I've appreciated Nicholas Jolley's book.

LOL. You take your role as historian pretty seriously. Thanks.

If A and B have the same properties, A=B. Show what properties physical possibilities have that logical possibilities don't or vice versa.

I put out an invitation to put up an argument for the existence of possibility that is distinct from logical possibility.

I don't see that you did that.

Explain how modal logic possibility is distinct from logical possibility.

I don't know.

I didn't read it. Should I?

Neither of you offered a reason to allow some kind of possibility that is distinct from logical possibility.

It doesn't appear that you followed the discussion MU and I were having prior to interjecting that it's logically possible to put the moon in your house.

then it is logically consistent with S both that P or that not P. It is fair to construe this as entailing physical possibility, meaning that for some proposition to be physically possible from the standpoint of an agent is for the truth of this proposition to be logically consistent with S. — Pierre-Normand

You disagreed with me while saying exactly what I said. Neat trick, Pierre.

Grab a hold. It's logically possible that you're from Kentucky.

Sorry.. I'm not explaining this well. Some cookies are iced with chocolate, some with strawberry. "You pick chocolate." and "You pick strawberry." Neither of these statements presents us with a contradiction (which is a way of saying that they're both logically possible.) You pick chocolate. Simply based on the fact that doing otherwise does not present us with a contradiction, Leibniz says you demonstrated free will.

Leibniz is dealing in logical possibility. So let's consider whether there really is any other kind of possibility. What argument would you put to Leibniz to convince him that there is?

Cyrenaic epistemology seems not to countenance any existential statements or denial of them at all. — The Great Whatever

So anti-realist. Hmm.

A precondition for understanding the world: that the world is always already conceptually articulated. — John

By the fool on the hill? :)

You have free will to the extent that there is no contradiction in your doing otherwise than you have. That's Leibniz's view. It's closely kin to the way possibility is apt to be understood in modal logic.

Diagnosing the underlying structure of what?

You're saying it's contradictory for a person to struggle to persuade an audience to accept determinism. That's true. I guess I was reading grander stuff into your original post... a precondition for understanding the world (whatever that is, I want one.)

The question remains, however, is whether or not science actually needed this basis. — darthbarracuda

I guess you could outline some alternate history.

We treat the possibility as different from a logical possibility. — Metaphysician Undercover

Not per Leibniz. He said that free will just amounts to the absence of contradiction in some alternate action being performed. I'm not saying you have to accept Leibniz's view. But since one of humanity's greatest minds contradicts you, you should put up some argument for your view. You can't just drop it on me as given.

Only a lawyer would think that acceptance of the potency of argumentation is a precondition for meaning.

The word of the day is: Leadbelly.

It-was-a-dis-AS-ter. --Searle

It was needed at the time. Physics as we know it was trying to be born.