That is an epistemological notion of the physical. Perhaps a metaphysical definition would be that an event or object is physical if and only if it has a spatiotemporal location within some reference frame.

To get a general skeptical conclusion of course you'd need to add a premise to the effect that to know that you see your hand you need sufficient evidence for knowing that you see your hand. If you add that premise, though, the Wittgensteinian approach that not all knowledge requires evidence comes in.

Going back to the original post here - insofar as you are trying to represent Descartes in any case - the argument would probably better be expressed as a modus tollens:
1) If seeming to see my hand were sufficient evidence for knowing that I see my hand, I would be able to distinguish the following two cases merely on the basis of seeming to see my hand:
a) My seeming to see my hand being the result of my actually seeing my hand.
b) My seeming to see my hand being the result of an evil demon playing with my mind.

2) Merely on the basis of seeming to see my hand, I cannot distinguish case (a) from case (b).

Therefore, seeming to seem my hand is not sufficient evidence for knowing that I see my hand.

That seems to get around the problem you are presenting the skeptic, since it is no longer being expressed in terms of two allegedly inconsistent premises. Instead it is expressed as one conditional premise, together with the claim that the consequent of that conditional is false.

In that sentence, I didn't mean "reality" literally

Like one or two other people on this site, it seems that as soon as you are caught out in a contradiction, rather than rethink your position, you simply change the meanings of words. I'll leave you now to go ahead and play Lewis Carroll's Humpty Dumpty all by yourself, and I suggest @jkg20 do the same.

@JKG20 said: "For the latter, their truth consists in the logical relations between propositions used to express the non-if-then-facts. "
You replied: "I wouldn't say it that way. When you referred to the latter, you're referring to metaphysical if-then facts. I wouldn't say that they're used to express the non-if-then facts of our everyday experience and pragmatic life. But they're the metaphysical reality that underlies our pragmatic experential world and life."

Regarding this part of your reply
"I wouldn't say that they're used to express the non-if-then facts of our everyday experience and pragmatic life."
Of course they are not used that way, we use straightforward declarative statements to express non-if-then-facts. If-then facts are expressed using conditional statements of the form if P then Q.

Regarding this part of your reply

But they're the metaphysical reality that underlies our pragmatic experential world and life

Presumably by the "they" you mean your if-then facts. You seem to be contradicting yourself directly when you then go on and say.

I make no claim for any reality or existence for the abstract if-then facts, or the infinitely-many systems of them.

I've only skimmed it, but typing in "scholastic roots of the private language argument" turned up this link:
Origns of the Private Language Argument

It's mostly focused on tracing the ideas in Wittgenstein's arguments against private languages within post Cartesian (and even more specifically post-Frege) tradition, but p 70 talks about some early Christian cleric called Arnobius casting doubt on the idea that language makes sense outside of communal context. So it is definitely a theme in thought prior to Locke. But that's as far as I'll be going with this - although it's an interesting topic in the history of philosophy, so maybe you should start a different thread "Calling all experts on Scholastic philosophy...." there might be one or two skulking around this forum.:wink:

Well, on a perhaps superficial reading of Locke, he had a philosophy of language whereby words signified ideas and not things in the world and the idea of language as resting on conventions and learning is problematic in that context if the conventions have to be agreed on concerning things locked away in the mind and not in the world. The idea that the use of words is based on convention goes back at least as far as Aristotle's On Interpretation but so too does the idea that words signify mental experiences. So the kind of tension that is at play in the paradox of learning colour words, and which strains at Locke's philosophy of language, is already there to find in Aristotle, who of course figured large in the Scholastic tradition. So it would be no surprise to me if at some stage there were a battle within Scholasticism over the priority of ideas or conventions in accounting for the meaning of words, and the "parlour game" of learning colour words might have been used as a sophistical tool. But now I'm just speculating wildly.

Well, the exposure of the fraud begins with Simpcox accepting a premise along the lines that if he has just gained sight then he ought to be able to prove it by naming the colours he sees. So there might be a kind of paradox in play, since we also have the premise lying behind Gloucester's reasoning: if someone can use the colour words accurately, that person has not just gained his sight.
There may have been some kind of philosophers parlour game at the time to show up a paradox about learning colour words which ran along the following lines. In order to learn the meaning of the word "black" say, we already have to be able to identify black things, but the meaning of the word "black" lies precisely in its identifying a specific colour, so if we can already identify that specific colour, we already know the meaning of the word "black" and so don't have to learn its meaning. On the other hand, if we cannot identify black things at all, we will never be able to identify what the word "black" is being used to pick out in the world, and so we will never be able to learn its meaning. Either way, we cannot learn the meaning of colour words. That would be a kind of variation on the paradox of learning that (as far as I am aware) get's its first airing in Plato's Meno.

I don't think anything to do with qualia would be lurking in the back of Shakespeare's mind when he wrote this scene, or any of the philosophically inclined people who might have moved in the same circle as he did. Of course, that does not mean you cannot draw something interesting out of the exchange, I just don't think anything like that was Shakespeare's intention. As I mentioned above, the philosophical context in which questions about qualia arise (ignoring the fact that that specific terminology doesn't crop up until the 20th century) doesn't really set down roots until after Shakespeare is several decades dead.
There are some sceptical arguments in Sextus Empiricus concerning perception of colour, of course, but even there I think it would take a post-Cartesian perspective to see them as showing that a wedge could open up between our capacity to name colours and our capacity to see colours. Those kinds of debate only really get going once empiricism enters the scene with Locke, Berkeley and Hume.

Specifically on the colour point, Gloucester exposes Simpcox by saying that in supposing he could name colours as he claims to be able to do, we would have to suppose also that it would make sense for someone to be able to name people they have never been introduced to. It's analogical reasoning, and you do see that used by Plato's Socrates to expose flaws in others positions. Is that what you are getting at?

I'd have to reread the play, but is it really that the courtier is supersmart or just not as gullible as the rest? Are you suggesting that Shakespeare is making a point that it is philosophically interesting how we get to agree on the use of colour terms? I think the kind of philosophical apparatus which makes that a problem - and it is basically the same apparatus that makes metaphysical solipsism seem coherent - doesn't really get into philosophical debate until after Descartes and so long after Shakespeare had shuffled off this mortal coil.

What do you consider to be the philosophers' party trick here? Pointing out that there is a difference between seeing a colour and naming a colour? Doesn't seem to be particularly tricky, more like obvious, but perhaps I'm missing something subtle in Shakespeare that you are seeing. About a hundred years after that play was written, an arguably more philosophically interesting question about what the cogenitally blind may or may not be able to do on regaining site was asked of Locke by Molyneux, concerning whether they could immediately recognise spheres by sight given that their knowledge of what a sphere is was garnered from touch.

Actually, not the undoubted champion - I'm forgetting that there are some strong contenders on other posts I've been involved in.

I humbly apologise for my spelling mistake - as it happens I am not Scottish at all, but I happen to have finished Wheen's biography of Marx not so long ago, so maybe that's an explanation of my inexcusable syntactic error. Do you think I should go through all of MO's posts looking for a spelling mistake to score a philosophical point? I didn't realise we were playing a game of ignoratio elenchi, but if we are I think I'd have to yield victory to MO - he is the undoubted champion.

A paradox?

No, just one more reason for concluding that the Free Will Theorem does not refute the PSR. I refer readers of this post to exchanges between tom, @Michael and myself on the Principle of Sufficient Reason thread, where that result was already established, apparently to everyone's satisfaction but tom's.

It's a marketing event for the promotion of porcelain goods.

historically the PSR has meant something stronger and more specific than just having some reasons or motives or inclinations for believing this or that.

And it still does for those who uphold it - such as Della Rocca. Framed in terms of "everything has an explanation" it turns out that for him the acceptable explanations are either citing causes or citing logical entailments, so it turns out to be more precisely "everything is caused or logically entailed by something else". This places some objective, or at least non-subjective, restriction on what will satisfy the PSR at any given time in the evolution of thought - not just any old excuse will do. Nevertheless, the notions of logical entailment and causation are not fixed (the former is probably more resistant to change than the latter, granted). This would also mean that although it is a restrictive principle, the meaning of the PSR evolves - citing tree spirits as the cause of noise in a forest no longer cuts the mustard, even if there are some people who might want still to believe in tree spirits.

OK, I'll look at that reference - as far as I am aware the Greeks proved there were irrational numbers, even if some of them weren't happy about it. In any case, even if there are choices in the ways of dealing with criteria (2) in the face of the proof, criteria (1) remains totally untouched. So, at a minimum, the authors of the article have made a mistake identifying the choice they are supposing the Greeks had before them. The choice you've presented the Greeks is between giving up the idea that there are irrational numbers at all (presumably by denying that there can even be squares covering an area of two square units) and retaining criteria (2), or just dropping criteria (2) in favour of something restricted to the use of whole numbers in expressing the rationals only. That makes a little more sense to me, but not much.

Basically, the authors need to work on the example a little more and expand on exactly what they take their criteria to be criteria for.

The irrationals show that criteria (2) as I developed it (which could be an incorrect development, I grant you) is just false - there is simply no "decision to make about which of the two criteria is more important to us" to quote the authors.

Well, if the two criteria are criteria, what are they criteria for? As I say, I don't think they can be criteria that provide us with the rules for telling us (or the Greeks) what a number is or was, since they are expressed using the very notion of "number". So they might be criteria for describing the use of numbers. If so, then (1) captures the use of numbers for measuring things such as geometrical lengths that are amenable to the application of the notion of a discrete unit. (2) becomes something like the criteria that ratios of whole numbers - i.e. the numbers used to count those discrete units - can be used to express all possible numbers. Does the proof that the square root of two cannot be expressed as the ratio of two whole numbers really have any bearing at all on criteria (1) thus understood? I think that the answer to that question is "No". If that is right, then the authors are incorrect about the Greeks facing a choice about which criterion needed to be dropped (or, rather, modified) - and it is mathematics itself that just hands them the fact that (2) is not adequate.

@jkg20

I have already said the labor theory of value is "fictitious."

I think LD Sanders was responding to the wrong person, and had me in mind when he threw the "theory of value is false" in your face. Having said that, I'd rather pick this up with you than LD Sanders, as I

I think LD Saunders was more having a dig at me, not you - but perhaps you just meant people like you who (I assume) hold some form or another of the labour theory of value.
For Marxists who try to eliminate the labour theory of value, apparently it is still a fairly active controversy
https://paulcockshott.wordpress.com/2018/04/05/did-marx-have-a-labour-theory-of-value/
Like the blogger there, I don't really see how Marx makes sense without some form of LTV, but always worth keeping an open mind.

The authors talk about criteria, not definitions (although, by giving criteria you might supply a definition I suppose). I don't think the Greeks would have defined numbers by those two criteria, for the very notion of number appears in the criteria, so the definition would be circular in a very unilluminating way.

It is an interesting paper - thanks for the link. I have one perhaps stupid question:
The two criteria the authors mention need actually be unpacked as the following (as far as I can see):
1) There is a one-one correspondence between numbers and lengths and there is an arbitraily chosen unit length.
2) Numbers can be expressed as ratios of the varying amounts of the arbitrarily chosen unit length mention in (1).

Is there really a choice as to which one to give up? Giving up 1) would be to give up using the notion of a unit of length, which would entail nothing could be measured.

Sophisticat is correct about PSR having a number of different formulations, but in some of them the notion of sufficiency just falls away (or is covered up, at least).

The PSR is these days often expressed, for example by Della Rocca, as the claim that everything has an explanation, and so the notion of sufficiency "disappears" in that formulation. So, let's say that someone proffers that A is explained by B. If your point about sufficiency (based on reading your first post on Heidegger) is that another person could come along and say "that's not enough of an explanation, because it has not been explained why Arather than C" , then (provided that A and C are somehow exclusive of each other, e.g. logically or physically) at least two responses seem available:

1) In explaining A by B, at the same time why A and not C is explained since C is excluded by A.
2) An explanation ofsomething different is being required; an explanation of C's exclusion by A.

If, however, C is entirely unconnected to A, then the question "why A and not C" would make little sense and so pushing the "that's not enough of an explanation" would be meaningless in the context.

All that, of course, is to take something like a "linguistic" turn in thinking about the PSR, but taking that linguistic turn seems to obviate any need to think about critieria for sufficiency - if only to replace it by the need to think about what counts as an explanation (or if you prefer the Wittgensteinian approach, what counts as giving an explanation).

I think the most sensible thing we can draw out from these various exchanges before we move on to other things, is that the distinction between logical truth and substantive truth is important and complex and is being totally ignored by MO.

@Michael Ossipoff

the fact that IF the additive associative axiom is true, THEN 2 + 2 = 4.

And here you display your equally superficial knowledge of number theory - I guess you pick that up from a cursory reading of websites as well as your philosophy. In most systems of number theory, the associative property of addition is not an axiom, it is a theorem that can be proven from the axioms of the theory.
I suppose there could be a number theory in which it could appear as an axiom, however, in those theories the conditional you give would be false, since you would need more than just the additive associative axiom to be able to infer that 2+2=4, you would need all the axioms of the system.
If you meant to say "Given all the axioms of number theory, then 2+2=4" - well, firstly, why didn't you say that? and secondly if that is what you meant, then what you meant is a tautology (not a simple one, but a tautology in the mathematical sense of being vacuously true under all interpretations of its symbols).
You might see this as quibbling, but the fact is that you are slapdash in your understanding of the difference between an axiom and a theorem is just one more indication of a slapdash mentality in general, and slapdash mentalities, whatever merit they have, do not merit being taken seriously.
I do need to wheen myself of making a fool of you, but I cannot go cold turkey it seems.

@Uber

'Marxism' is a catch-all word for many different concepts

Agreed, and I'm guilty of being one of the people that tend to compartmentalise Marx's economics from the rest of his theorizing. I happen to think that you can drop the historical materialism (particularly the materialism part) and retain the economic part without contradiction, although I could always be wrong about that.
The transformation problem has a number of different attempted solutions - Kliman's is the one I'm inclined to go for, if only because it seems to involve the most sympathetic reading of Marx's economic theory. There are of course, as you point out, problems with measuring the role of labour in the production process, particularly when the notion of labour in use is that of socially productive labour (and so no straightforward count of hours or calories expended is going to do the job). However, these are problems that seem in principle manageable.
As for the labour theory of value (as understood by contemporary Marxist economists) being determinisitic, the evidence for it is statistical, so it seems to be regarded as a stochastic theory rather than a strictly deterministic one.

@Bitter Crank

A great deal of wealth is produced by the manipulation of currencies, stocks, bonds, etc.

I believe you and I are largely on the same page, but in terms of Marxist economics, one thing that bothers me about this remark is that Marx is pretty clear that real wealth (i.e. surplus value as profit) cannot be created through the mere circulation of capital and, arguably, manipulation of financial instruments is precisely and only that. It's clear that the illusion of wealth can be created in this way, but illusions that are in the end exposed for what they are (and when they are exposed, they manifest in one form of economic crisis).

@LD Saunders

We know the labor-theory of value is false,

We know no such thing. As I stated in my earlier post in which I questioned how much of Marx you had actually read, I said that there is empirical evidence to suggest that the labour theory of value is actually true. Sure, we can debate that evidence if you like, but the fact that there is such evidence to be debated already falsifies your claim that we know it to be false. It may not be true a priori, but that's not the same thing as being false.

@LD Saunders

Marx stated that workers would go to the lowest level of poverty, and that most definitely did not happen.

Where does he state that? Marx recognised that real wages could go up as well as down in capitalist systems.
You may have read Marx, but you don't seem to have understood him.

OK, I'll have to read van Inwagen, which I don't believe I ever have, but if by "way things are" he simply means "way things are independently of what anyone thinks", it seems to boil down to good old fashioned realism. Any other conception of the way things are might have to give a role for consensus amongst some sorts of epistemic agents as providing one of the criteria for truth. Anyway, as you say, it's really a topic for a different thread (or reactivating a dormant one).

In brief your argument seems to be that if realism is true (in the sense that the truth of a proposition consists in its having a certain kind of connection to a reality which is independent of our knowing it), then no matter how much agreement is arrived at concerning any given proposition, that proposition could be false.
Seems perfectly cogent to me as an argument. It's the structure of a lot of skeptical arguments. There are, I suppose, limit cases such as certain arithmetical propositions, but perhaps even there the rule-following considerations from Wittgenstein come into play.
So, the next question is, what reasons are there for believing that kind of realism to be true?

I think the author takes it to follow based on the idea that insofar as propositions are concerned, the PSR requires a reason for each proposition. However, the author considers that Wittgenstein thought that not all propositions can be given a reason because reason giving has to come to end somewhere. Not sure how that works as Wittgenstein exegisis. In the context of the article it might work if the PSR was taken by Wittgenstein to have scope only within the context of a "reason giving game", but insofar as the PSR transcends the boundaries of any particular "reason giving game", it doesn't look to me like Wittgenstein is denying the PSR.

Part of the problem is trying to simplify things into a neat theory, that's what's problematic. I don't think reducing it to an "explanation" would help, it just begs-the-question, besides it seems quite possible that some reasons or causes have no explanation.

Not sure I understand what you are driving at here. What question is begged by framing the PSR in terms of explanations? Even when couched in terms of the requirement for explanation, it retains the appearance, at least, of something that is capable of being true or false, it just renders the whole reason/cause distinction that the author of the article homes in on as somewhat irrelevant to deciding whether it is true or false.

You might be right that there are things that happen that have no explanation. The PSR couched in terms of explanations rules them out, so if you could cite an indisputable example of such an event, the PSR would indeed be false.

Oh, I cannot help myself, correcting conceptual errors is addictive.
@Michael Ossipoff

I've been repeatedly emphasizing that, regarding the abstract if-then facts that I've been referring to, there' s no reason to believe that any of them are "sound", in the logic sense There's no reason to believe that any of their premises are true.

Take the last sentence, to what does the possessive pronoun "their" refer? Your if-then facts. Facts do not have premises, arguments have premises. Your writing is peppered with these kinds of errors, and thus manifests an at best superficial appreciation of philosophy, and in all cases a very deep confusion. So now you might try to say, "oh, but you foolish boy, by "premise" I of course mean the "if" part of if-then facts, so if-then facts are arguments and so do have premises". Well, if you are going to take that kind of Humpty-Dumpty view of language, wherein words can mean whatever you want them to mean whenever you want them to mean them, the only person who will ever understand you is you. However, I get the distinct feeling you really do not care whether you are understood by others or not.

Thanks for the advice - I think I will indeed move on to other more interesting threads.

Perhaps formulating the principle in the terms "Everything that happens has an explanation" would bypass the problematic distinction between reasons and causes? Then one could explain something either by giving a reason (in Wittgenstein's sense) or by citing its cause (in Wittgenstein's sense) as appropriate (and perhaps in some cases by doing both). Interesting that Wittgenstein might have held a statistical conception of causality, rather than a strongly deterministic one.

@Michael Ossipoff

We aren't speaking the same language. There' s nothing to say to your comment above, other than to refer you to SEP, so that you can find out what the terminology consensus is, and what "fact" means, in that consensus.

The central issue here is not about facts, the issue is about the difference between vacuously true propositions - i.e. tautologies that are made true by virtue of their logical form alone - and substantively true propositions, which are made true by facts. Of course, there is the fact that tautologies are made true by virtue of their logical form alone, but that is not the fact expressed by any tautology - the tautology expresses nothing, that is why they are true no matter what.

You suggest that, in addition to the facts, there’s something else (concrete, fundamentally, independently and objectively existent material things and stuff) that the facts are about..

No, nothing I said implied or suggested a belief in the existence in "material things and stuff". What I do think is that if there are facts then they are not atomic, they have identifiable parts. The fact that the Elizabeth tower of the Palace of Westminster is 316ft tall, for instance, and the fact that the Elizabeth tower of the Palace of Westminster houses Big Ben, are two distinct facts concerning one thing - the Elizabeth tower of the Palace of Westminster. Now, you might want to argue that what I am calling the Elizabeth tower of the Palace of Westminster is in fact some bundle of facts itself, but that would take argument, not simply assertion and appeal to the "authority" of Michael Faraday. You might like Wittgenstein's Tractatus - there you really do have a philosopher who believes that the world is the totality of facts not of things. Funny thing about the Tractatus, though, is that Wittgenstein doesn't give an argument for that claim, he just asserts it.

For you, I recommend less assertion and more reading.

For you, I recommend more careful thinking and less incoherent babbling.