“If all Slithytoves are brillig, and all Jaberwockeys are Slithytoves, then all Jaberwockeys are brillig.”

…is a conditional proposition

…and it’s a fact.

It’s a true conditional proposition.[/quote]

It is not a fact, and it does not even express a fact. At best it is a logically valid argument couched in the form of a conditional proposition. Any logically valid argument can be expressed as a conditional proposition, where the antecedent is formed by the conjunction of the premises and the conclusion forms the consequent. But where a logically valid argument is expressed as a conditional, it becomes a tautology, and tautologies are vacuously true - as @tim wood says, true uniquely in virtue of their logical form, not true in virtue of their content. What makes logically valid arguments interesting, from a philosophical perspective, is when they purport to be sound, which means when they are presented along with the assertion that all their premises are true.
You have yet to present us with a logically valid argument for the existence of reincarnation, when you do, we can address the matter of its soundness.

Thanks - but it appears to be just a link to a page of this thread - could you relink?

Regarding premise 3) - one thing to bear in mind when discussing QM and truth is that you have, on the one hand, the formalism of QM which provides extremely successful means of predicting experimental outcomes (and subsequently all kinds of useful devices have been constructed) and then you have interpretations of that formalism, of which there are quite a few.

Regarding premise 1), I'm not sure what the argument there is. It seems to me that PSR is compatible with more relaxed forms of determinism, but I'd be interested in real arguments to the contrary (and specifically not arguments of the form "the Free Will Theorem proves it").

Regarding premise 2), the idea is that under a very strict understanding of determinism, if the state of a system at time t is fully determined, then there is only one possible state for the system to evolve into. QM seems to imply that even if the state of a system at time t is fully determined, there is more than one possible state into which it may evolve.

I don't know. I do know that I have met people who are unhappy and frustrated because the world does not meet their expectations of it, so I suppose lowering their expectations might help them. Is that what you are getting at?

Taking the opportunity to respond on tom's behalf, I think the usual argument concerning QM and PSR is along the following lines:
1) If PSR is true, then only a very strict understanding of determinism is true.
2) If QM is true, then a very strict understanding of determinism is false.
3) QM is true.
Therefore a very strict understanding of determinism is false.
Therefore the PSR is false.

All 3 premises are open to debate, of course, but that seems to be the gist of the QMers v the PSRers debate.

If by "a lover of opinion" you mean "one who is unwilling to admit to error and will make all manner of argumentative tricks in order to avoid admitting error" then I've certainly encountered a few of those on this forum.

Yes, shame on you @Michael for providing Tom with a perfect opportunity to avoid responding to the challenge :wink:

If choice is not possible, then there can be no sense in which there is information on which a choice can be made.

Nobody is saying that choice is not possible. What the PSR entails is that there is no such thing as freedom of will in the sense used by the authors of your pet theorem. Denying freedom of will in that sense is simply to insist that all choices that do exist are the outcomes of functions of information accessible to the choosers. That's all. Nothing you have said so far provides an argument that science becomes impossible if free will in that sense is denied.

OK, well I guess the authors meant something like "the choice is not the outcome of a function..." so it seems reasonable to think that the PSR does rule out free will in that sense. So, the next question for @tom would be: why would it follow that science is not possible if every choice an experimenter makes must be the outcome of a function of some or all of the information accessible to him or her?

Tom seems to believe that denying the existence of free will in this sense entails that science is not possible. I'd like to see the argument for that, since - after all - science is possible, and so the possibility of science would prove the existence of free will (in that sense). But as indicated, there's some argumentative work to do to reach that point.

Just say that humans having free will falsifies the principle.

But please don't just leave it at that. It would take a very specific understanding of what free will amounts to for its existence to refute the PSR. Once that specific conception is explicitly stated, the issue then is what happens if we deny that free will in that sense exists?

Infinite, but ever decreasing, circularity perhaps :wink:

:up: Thank you for summing up concisely exactly what I've been trying to express in my admittedly rather long winded fashion. Let's hope that tom now drops this whole FWT refutes PSR gambit and picks up on the more interesting elements of some of his posts.

Read the paper - the authors are quite clear that the FWT states precisely and only that the measurement outcomes are free in the sense that the measurement choices are free. They even talk about measurement outcomes inheriting freedom from the freedom of choice. If that sense of freedom allows that choices can be caused, then the measurement outcomes are free in the sense that they can be caused also, and once again we are back to FWT being irrelevant to the PSR.

There appears to be some fundamental difference of understanding about what the FWT is, so in an effort to get at precisely what that difference of understanding might be, let me be clear on what my understanding of the FWT is and how that understanding entails its total irrelevance for PSR. After this, I think I'm going to have to move on to something else as, for one thing, its becoming a little boring saying the same thing over and over again in different ways.

The FWT is a conditional theorem to the effect thatif there are uncaused events of one specific kind, then there are other uncaused events. In the original paper the uncaused events of the antecedent are initially taken to be free will choices of experimenters about what measurements to take, and the uncaused events of the consequent are the outcomes of the measurements.

That is my understanding of the content of the FWT as expounded by the authors of the original paper, if you disagree with that understanding, please be precise as to what it is about my interpretation of the FWT you object to, and propose an alternative. Note that I am not addressing the authors' method of proving that the FWT is true - given the axioms they work with, and the rules of inference they rely on, their reasoning seems faultless to me. You tell me that they are mathematicians by training, so I'd expect nothing less in any case. What follows from this point on is based on my understanding of the content of the FWT being the correct understanding.

If there is no such thing as free will in the sense of it entailing the existence of uncaused human actions, then the antecedent of the FWT (framed in terms of free will) is false. Of course, the FWT itself remains true in such conditions, but trivially true by the classical laws of logical implication (which are the laws of inference being used by the authors to prove the FWT). Specifically, if the antecedent of a conditional is false, the conditional itself is true, but we cannot infer anything at all concerning the truth or falsity of its consequent. Now, the PSR - under many interpretations at least - entails precisely that there is no such thing as free will in the sense of allowing for uncaused human actions. So, under those interpretations of PSR, the antecedent of the FWT conditional is false. So, even if the PSR is true, FWT remains nevertheless true. If the PSR is false and there are uncaused human actions, FWT is also true, and we have the bonus of being able to use modus ponens to conclude that its consequent is true as well. Therefore, even if FWT is true, PSR could be either true or false. This is as much to say that the truth of the FWT is irrelevant to the truth or falsity of PSR.

But I cannot resist one last parting word before moving on - I know, it's a weakness of mine:
Consider the following schemas:
1) It is possible that P
2) It is impossible that P
3) It is not possible that P
4) It is not impossible that P

Here P stands in for some proposition or other.
Let's suppose for the moment that P is the proposition that "The round copula is square".
Well, since anything that is round is not square, substituting this value for P into 1 and 4 gives you a falsehood, and into 2) and 3) gives you a truth. So, there is at least one impossibility. Here's another P = "An inedible apple is perfectly edible". So that's two impossibilities, and I've only just gotten started.
Now let P="Some grass is red". Under this substitution 1) and 4) gives you truth, whilst 2) and 3) gives you falsehood. Another substitution with the same result: P="There are green swans". So, two possibilities, and I could keep going.
What is the point of all this? Two things:
1) Whatever you think of possibility or impossibility there are indefinitely many specific possibilities and impossibilities.
2) The schemas 1 and 4 are logically equivalent, as are 2 and 3. This means we can define the possible in terms of the impossible and vice versa - the logical equivalence implies that they are two sides of one and the same coin, that coin being the concept of modality.

On the comparison of humans with animals, I'm not sure animals are capable of joy and sorrow. They are perhaps capable of feeling pleasure, pain and other forms of comfort/discomfort, and feelings of comfort and discomfort may be at the base of joy and sorrow, but joy and sorrow are much more sophisticated notions than pleasure and pain, and perhaps even to feel joy and sorrow requires self-awareness.
I remember reading JS Mill (a long time ago) saying that it was better to be a human being dissatisfied than a pig satisfied and I just thought that the idea of a satisfied pig was truly bizarre : a well fed pig makes perfect sense, of course, but asatisifed pig, what the hell is that supposed to be?

Nope, you've lost me completely - I'll have to move on to other posts.

Well, don't get me wrong, I'm not a proponent of probabilistic causation, but the basic idea would seem to be that the challenge QM poses for the traditional account of causation is that the traditional account entails a certain conception of determinsim which can be captured in the following idea: all the events leading up to the state of a system at time t allow for only one possible next state of that system. QM, well some interpretations of QM anyway, entail that all the events leading up to the state of a system at time t allow for many different possible next states of that system, each state being more or less likely, but no state being impossible. So, if that is right, QM undermines that specific notion of determinism. Probabilistic conceptions of causality attempt to keep some aspects of causality, but drop that specific conception of determinism, allowing that future states of systems have a probabilistic distribution, but are nevertheless in some significant sense caused by the existing state of the system, thus rendering causation compatible with (some interpretations of) QM.
That seems to be the gist of it, as I say, I am not a proponent so cannot really provide you any more details - there are plenty of references in the link I provided if you are interested. A probabilistic account of causation may be right, it may be wrong, it may in the end not even make sense, and may not in the end be compatible with all interpretations of QM. One thing is for certain, though, the FWT is irrelevant to deciding on those issues, just as it is irrelevant to the status of the PSR.

I'm surprised nobody has mentioned Hegel yet on this thread. I'm no expert, but he did introduce an evolutionary conception of existence, so if reality is always evolving, so is our philosophy, and the evolution of our philosophy feeds back into the evolution of existence, so it would should be no surprise that philosophical explanations reach no final end. Maybe that's a bit of a cardboard cutout of Hegel, but it perhaps offers a different way of dealing with the trilemma.

The FWT does not prove that there are uncaused events, it proves only that if there are uncaused events (the free will choices of experimenters) then there are other uncaused events.

Really?

Yes: take a look here for instance probabilistic causation

Which pseudo-random number generator do you propose to use? How will you map the output of the number generator to the buttons?

Why are you asking me for specifics like that - I'm not proposing that they should be used at all. All I'm saying is that the very notion of a pseudo-random number generator is that there is a causal determination of the numbers that they churn out.

The PSR has never driven human discovery. It can't do that.

Well perhaps I chose an inappropriate metaphor - but the idea that everything is explicable is a motivation for pursuing explanations, and science is - amongst many other things - the pursuit of explanations.

The FWT also holds if the decision is made by a random number generator, which exist BTW.

Well, quantum random number generators exist if that's what you mean, but if you are going to use that as a definition of free will used in the FWT then the FWT becomes an empty tautology saying that quantum systems have the freedom that quantum systems have.

2. Every event has a causeThe MadFool


This is proved false by quantum mechanics.

Not really - there are probabilistic conceptions of causality that are perfectly compatible with QM.
What some people claim is that QM refutes the "ex nihilo nihil fit" principle (that some people see embedded in the PSR) because of the fluctuation of virtual particles. But as @Thorongil points out, when QMers are pushed on the point of what these virtual particles are, it actually turns out that you are not really getting something from nothing at all.

It seems odd that someone would give up the ability to chose which button to press, rather than question a cherished principle.

Odd, perhaps, but if that's where a true principle or an apriori principle of thought or whatever it is taken to be leads, so be it: a principle that drives human discovery in one way or another is not to be discarded simply because it leads to apparently unpalatable results. Anyway, the whole freedom to choose/freedom of will/compatibilism/determinism debate has its own thread (several of them in fact), so that part of our discussion is better taken into one of those unless you think that there is an real argument that the PSR is undermined because it leads to determinism which in turn leads to the meaninglessness of the PSR (which is what I thought you were hinting at earlier, and which as I say is an interesting line of thought, but one which is entirely independent of the FWT).
And no, FWT has a very specific but undeclared notion of freedom of will in its antecedent, and it is that notion of freedom of will that is (arguably) undermined by the PSR. Pseudo-random number generators are not truly random - their outputs are in principle predictable and explicable and at base a matter of cause and effect, and that feeds through into any measurements finally made on their basis that the measurements to take are "chosen" by such a machine.
The FWT really is irrelevant to deciding whether the PSR is true or false or something else entirely.

Do you see that one of them "impossible" is a principle of constraint,

No, I don't see this, since as I pointed out, what is going to count as impossible is going to change depending on the circumstances just as much as what is possible.

When we approach from the other way, "possibility", we have all sorts of random criteria as to what constitutes possibility, allowing for infinite possibility

Firstly, the criteria I mentioned for possibility are not random in the least. One set of criteria constrains the possible within the bounds of the known laws of nature. Another set releases that restriction but applies the laws of classical logic. Those are not random criteria, but clear and precise ones.

Secondly, nothing you say about the impossible rules out their being infinite impossibilities.

"Possible" and "impossible" are terms that come together as a package or not at all.

I take the PSR to be an epistemological, not an ontological, principle.

I think this is probably how those who wish to treat it axiomaticallly in some sense need to take it - something like a rule for thought, which is what @Srap Tasmaner seems to be getting at. But, certainly one way of looking at it is that the PSR pushes at that very supposed boundary between the epistemological and metaphysical. After all, your second paragraph seems to be making some Kantian-style metaphysical point about what couldbe for us on the basis that this is restricted by the PSR. Also, considering the use to which it has been put to in the past by Leibniz, Spinoza and Schopenhauer amongst others, it is pretty clear that some significant thinkers have regarded it as having metaphysical import (which does not, of course mean that it does just that there is some reason for thinking that it might). As @tim wood says, it's a bear of a topic.

The PSR is refuted because the laws of physics disagree with it. The assumption being that an experimenter possesses sufficient freedom to press one of a number of buttons.

You cannot refute a principle on the basis of an assumption which the principle (arguably) entails is false: that's called question begging.

If the assumption of the ability to choose a button is false, then the laws of physics tell us that we inhabit a superdeterministic conspiracy. I'm not convinced that PSR has any meaning in that scenario.

That's a different argument entirely, and quite an interesting one - along the lines of the PSR being self-stultifying.

In all cases, the FWT paper is irrelevant anyway.

ex nihilo nihil fit.

Well, and I'm not saying I agree with this, but I've heard some people claim that the virtual particles of QM are precisely things for which ex nihilo nihil fit (and with it the PSR) is false.

Would the PoSR not be itself a brute fact?

Sly move - turning the PSR against itself. Indeed if it is to be treated as an axiom, it's truth might have to be taken to be a brute fact, and that would seem to indicate that the PSR is false. I suppose it is here that the exact formulation of the PSR becomes important. Loosely speaking its the claim that everything has an explanation. We could try restricting the domain of quantification to just events, say, in which case the PSR is not something that needs to be explained, since it is not an event. That seems like cheating, though. So let's assume we have to give an explanation even for the PSR, which would mean that there were principles upon which even the PSR would be based, but then those principles themselves would, by the PSR, have to have their explanations....and here we get to Schopenhauer's point. There might be an infinite regress here, on the other hand, perhaps we can construct a virutous explanatory circle where the PSR gets justified by some principles which in turn get their justification from the PSR.

Interesting, how so? Naively, the way to refute the PSR would be to establish that there are somethings that occur for no reason at all. Is the point that we would then need to answer the question "Why should the mere fact that something occurs for no reason at all refute the PSR" by relying on the PSR?

And, If I remember correctly, the Principle of Sufficient Reason is not mentioned in either of the FWT papers

That is true, but I thought your position was that the FWT refutes the PSR. It doesn't, and precisely because of the fact that the theorem is a conditional whose antecedent bears on the PSR, and they don't establish that the antecedent of their theorem is true.

I fear you are confusing facts with propositions:

There are abstract if-then facts.

If all Slithytoves are brillig, and all Jaberwockeys are Slithytoves, then all Jaberwockeys are brillig.

That’s true even if none of the Slithytoves are brillig.

That’s true even if none of the Jaberwockeys are Slithytoves.

That’s true even if there are no Slithytoves, and no Jaberwockeys.

When I say that there are abstract if-then facts, I mean only that they “are”, in the sense that they can be stated. I imply or clam nothing about the matter of whether or not they’re “real” or “existent”, whatever that would mean.

In the above quotation the following conditional:

If all Slithytoves are brillig, and all Jaberwockeys are Slithytoves, then all Jaberwockeys are brillig.

is a conditional proposition, which is a compound proposition claiming a relation of entailment between its component propositions. Propositions might be abstract entities (in fact they probably are) and by extension conditional propositions are also abstract entities. However, facts are usually regarded as those things that make individual propositions true. Insofar as conditional propositions are true, though, we do not introduce "if-then" facts to make them true, since the truth or falsity of conditional propositions is entirely accounted for by the truth or falsity of the antecedent and consequent. This is true for all compound propositions - their truth or falsity is accounted for entirely by the truth or falsity of their component propositions plus the truth-table rules for the logical connectives between those component propositions.

Of course, by definition, a fact is true.

This is a strange definition of a fact, the usual definition (philosophically speaking anyway) is that a fact is what makes true propositions true.

Don't get me wrong, there are all kinds of philosophical issues with what I have been saying (e.g. if facts make true propositions true, what makes false propositions false?) However, you seem right from the beginning of your proposal to be conflating notions that need to be distinguished, and once you start doing that, the rest of what you say becomes nigh impossible to follow.

With the caveat that I have only skim read the article, the authors do nothing to recuperate their philosophical credentials by the end of the paper. Essentially the point seems to be that given certain assumptions about transmission of information, and possibilities for experimental outcomes, those outcomes are determined by choices made concerning measurements to make. The theorem then states that if those choices are the spontaneous acts of the free will of the measurement takers, then the outcome of the experiments is not determined by anything leading up to the measurements' being taken. Well, it would be a more interesting theorem if it were a biconditional rather than a mere conditional, since the conditional is (under classical rules of deduction) true, trivially, in those cases where the antecedent is false. The authors do absolutely nothing to establish that the antecedent is true, and do not even put any flesh on the bones of what they take to be "free will".
I await refutation from anyone who has read the paper more closely than I have - as I say, I have only skim read it - but as it stands my feeling is just to lump the authors into the category of competentent physicists but bumbling philosophers, and since the status of the PSR is a philosophical issue, they don't really have a great deal to contribute.

Admittedly I've only just started reading the article, but they appear to be helping themselves to the notion of free will, which is precisely one of the notions that the PSR bears upon, and if so, they are not so much falsifying the PSR but begging the question against it. I'll continue reading their paper, but the philosophical roughshod-riding they engage in at the begining gives me initial reason to doubt that they have anything philosophically cogent to contribute to the debate about the PSR.

If I love an opinion and the opinion is true, does that make me a lover of truth or a lover of opinion, or both at the same time?