I'm certainly not saying that everything Berkeley said is true, but in order to attack his position, you need to attack his position, not a misrepresentation of it.

If the observer can exist without being perceived, why does reality need to be observed to exist?

Again, not all of reality does need to be observed to exist for Berkeley, minds and souls are real for Berkeley, and so part of reality. Berkeley has a two tier ontology: minds/souls and, in awful modern parlance, the contents of mental states. In fact, God has a special role for Berkeley, so perhaps it is a three tiered ontology. The dependence of mental contents on minds/souls is what he spends a good deal of time trying to prove, so if your question is "why do the contents of mental states need to be observed to exist, given that minds and souls do not?", then Berkeley has a range of arguments in response, some better than others. Berkeley assumes that everyone is prepared to accept as a minimum the differentiable existence of minds and their contents, and he attempts to argue that the latter's existence is dependent on the former's.

Addendum.
I could perhaps also point out that for Berkeley, minds/souls are substances, and the conception of a substance he had, and shared with his contemporaries, was that substance is simple and incorruptible and cannot be created or destroyed. It is the very nature of substance that it exist, so no questions about its dependence on anything else make sense. So your question to Berkeley may be more along the lines of "Why is there substance?", or "Why are there substances?", but that looks a little like "Why is there something rather than nothing?", which is an entirely different matter than addressing questions about dependencies between tiers of existence.

Don't forget that in Berkeley's metaphysicsesse est percipi does not apply to perceiving beings. For Berkeley, as perceiving beings, we do not require to be perceived to exist. We may not even need to perceive to exist, but that depends on what one includes under the banner of perception.

Thanks for the response, a couple of follow ups:
"In my view, instrumentalism threatens to collapse into an uninteresting solipsism."
How does instrumentalism, if tied with commonsense realism, lead to solipsism? Perhaps instrumentalism tied to idealism of some kind might, but the argument on the link I provided seems to be trying to bolster commonsense realism, on the grounds that the alternative winds up in incoherence. Which leads me to the second follow up, which is just a repeat of my initial question: how would you respond to that argument?

Taking modern physics seriously yields a conception of reality very from the world-simulation of one's everyday experience. — David Pearce

One can take modern physics seriously in at least two distinct ways: instrumentally or realistically. Taking it realistically has been argued to lead to incoherence. What would your reply be to this kind of argument : https://metaphysicsnow.wordpress.com/2018/03/29/common-sense-versus-physics

However, as far as I can tell, the external world is inferred, not perceived. — David Pearce

Hello David. Do you have an argument for why, as far as you can tell, the external world is inferred and not perceived? Is it some version of the argument from illusion/hallucination? If so, how do you respond to the usual criticisms of these arguments by externalists, i.e. that these arguments tend to confuse metaphysical with epistemological issues.

If you inflate a balloon, the objects you draw on it inflate too. In reality, objects in space stay the same size. — Gary Enfield


That's impertinent to the analogy; and the latter assertion may not be verified (I'm not accredited to comment on it). — Aryamoy Mitra

Aryamoy Mitra is right. The analogy is supposed to elucidate the idea of a measured spatial difference between two things being, on the one hand, the effect of an expansion of the framework used to measure distances, and, on the other, being the effect of the motion of things measured within that framework. The effect only becomes noticeable at relatively large distances, which is why it will be difficult to see the changes in the expansion of small dots on a balloon, but relatively easy to see the gaps between them increasing. Change the details of the analogy, and have the small dots replaced by confetti held in place by electrostatic forces, such as that provided by glue. There, the expansion of the items between which the distances are being measured is no longer an issue at all. Amending the analogy that way, incidently, is pertinent, since long before Einstein, it was recognised that electromagnetic forces overwhelm gravitational effects between relatively small masses at relatively small distances. This is why, even if the spacetime volumes contained within what Austin used to call "medium sized dry goods" are expanding, the effects of that expansion would be unnoticeable to us, at least with the equipment we currently have.

:up: Thanks for that clarification.

Firstly, the guy talks about space expanding, when space is probably not expanding - but the objects within it are just spreading out. That is an important difference. (If space were truly expanding, the objects within it would also be expanding/swelling - and they're not).

The standard answer to this is, I believe, that at small scale distances, e.g. between the atoms that make up bodies, gravitational effects like expansion of space are trumped by the effects of electormagnetic, strong and weak forces acting between atoms and so on. Hence objects made up of atoms etc do not expand whilst the space between those objects does, or at least can.

1 Doesn't really break the "no object faster than the speed of light" principle: as per my post above, the speed that galaxies appear to be receding at is a function of both the velocity of the galaxy which is sublight and the expansion rate of space, which is not a speed at all.

2 New one to me, I'll have to look it up. Is it yet another case where QM and relativity clash?

Nothing, or more strictly no object, can accelerate beyond the speed of light, including galaxies, and that is according to both special and general relativity. Galaxies far far away from us appear to be receding at speeds greater than the speed of light, this is true, but, according the physics I was taught anyway, which of course may one day be superceded, this is a function of at least two parameters, the velocity of the galaxy and the expansion rate of space. However, space is not a thing that has a velocity: an expansion rate is not measured in metres per second, but in metres per second per relative distance, it has the same units as frequency, not velocity.

The equations of special relativity entail that nothing can accelerate up to or beyond the speed of light, taken as the constant c, since the logical consequence would be a division by zero. Einstein was clear about that. This says nothing, of course, about the possibility of the existence or non existence of things that travel at speeds above c, it just rules out those things having accelerated to those speeds from sublight speeds. Einstein was always clear that fixing c as a constant for all frames of reference was an assumption, and one that would be finally justified by empirical results, as it has been numerous times. Dimensional analysis has a role in physics, of course, but as far as I'm aware it's just a basic tool to avoid simple errors, and to use if for that, you need to get the dimensions right from the beginning.

Suppose one were to admit that existence is a predicate. You still need to argue that existence or non existence are perfections, after all, maybe there are no perfections at all, or maybe perfection is inapplicable to either existence or non existence. Forget not, also, that whatever argument you give, its premises must be more acceptable than the conclusion that god exists is rejectable.

↪jkg20
The paradox is in the image - not in the actual number of grains of sand.

The only images that might be considered paradoxical are of the Rescher variety. Where does the paradox lie in the image of a grain of sand? Where does the paradox lie in the image of a pile of sand? If your suggestion is that the paradox lies in the fact that we are somehow trying to force the image of a grain of sand to "align" with an image of a heap of sand, I refer you to my original quotation.
The paradox is in the concept of a heap. If one were an antirealist, that might lead one to thinking that paradox is also a feature of the world. On the other hand, one might just blame it all on vagueness and walk away.

1. Either nonexistence is a mark of greatness OR Existence is a mark of greatness [premise]

Start at the beginning. Why would anyone accept this premise? It's not as if we have covered all the logical ground just by capitalising the disjunction, since maybe neither is a mark of greatness, since greatness, in the sense required by the argument, simply has no marks. The problem with all arguments for god's existence is that you need to give people more reason to accept the premises than to reject the conclusion, and that is an uphill struggle.

How many grains of sand does it take to make a pile?
How many images of grains of sand does it take to make an image of a pile of sand?

The first question gets the sorites paradox going. The second question is nonsensical.

I just want to stick an oar in here for Descartes. Regardless of what anyone might have to say about his motivations and personal hygiene, he has and has earned two monikers: "father of modern philosophy", "father of modern mathematics". To those who want to criticise him frivolously, I"m inclined to say "well, let's hear one of your ideas". Almost single handedely he managed to divert the Aristotelean intellectual obsession with with the contrast between matter and form, to focus attention instead on the distinction between matter and thought. In the final analysis there may be no such metaphysical distinction to be made of course, and here I doff a cap to Spinoza. Nevertheless, Descartes works liberated mathematics and empirical science from the chains of the church, and we all owe a debt to that man, even if we do not agree with everything he claimed to be true.

OK, well thanks to you I've been able to look into an aspect of philosophy I've not really considered in relation to this particular issue in metaphysics. I took a look at some of the history behind the development of semiotics, and, if we go back to the Greeks where everything begins, it appears that they had no single notion of a sign, but two: semeion, and symbolon, the former being something along the lines we might express by saying yellow skin is a sign of jaundice, i.e. a kind of natural correlation between two things which is arguably mind independent, with the latter being the kind of thing we might express by saying that a cross on a map is a sign for a church, where mind dependent conventions are presupposed. Then we get Augustine who comes along and uses, in Latin, a single word signum to talk about both, and that's where semiotics as a general science of signs appears to get going, although it gets forgotten about for a few centuries thanks to Descartes. A fundamental question that seems to divide semioticists from non semioticists appears to be whether Augustine was showing philosophical insight by doing what he did, or whether he was simply conflating two notions that ought to be kept apart. I'll have to continue my reading to see what side, if any, I end up on :wink:

OK, so at the risk of putting words into your mouth, one kind of triadicism is the view that all reality arises from pure, unstructured indeterminateness. I guess we see that in Hegel's analysis of Being/Nothing/Becoming, although he often leaves me at a loss. I am presuming that the initial indeterminateness of which you speak is to be thought of as the ball balanced at the apex of the dome, so if that is wrong, what follows can be ignored. If that is right, though, then I get that the slightest fluctuation, no matter the source, or even if there is a source, can set the ball rolling, and I presume the ball's rolling is a metaphor for our experienced determinateness of actuality. What, though, stops the ball from just going straight back to a balanced initial state, i.e. even if the symmetry of indeterminateness is broken, randomly or otherwise, what stops it from simply reestablishing itself? We know that what the metaphorical ball is representing does not do that, because we are living through actual, albeit fleeting, determinate moments. If we take the example non metaphorically, we of course have gravity and we have laws of motion discovered/developed from which it is entailed that the ball will not return to its initial position but will follow inexorably a path we can predict. (We can hedge that prediction if necessary, but in a perfectly determinate and lawlike manner, by including the vanishingly small, but determinate, possibility that all the molecules constituting the ball suddenly disassemble and reassemble themselves at the apex. I also do not think it matters in understanding the metaphor whether we take gravity in a Newtonian sense as a fixed force acting between bodies, or an Einsteinian sense as being the manifestation of the determinate large scale distribution of mass through spacetime, but I might be wrong about that, perhaps it does matter in understanding the metaphor which approach is taken.) Taking the example literally, those physical laws exist independently of those specific initial conditions and gravity, if you like, is a determinate and permanent fixture of the background. Thus the ball's path is explained. Now, if to understand the metaphor we have to think that it is the future that is performing the gravitional role, then the future also has to be understood as something fixed and with a determinate structure. I'm not saying here that the future has to be regarded necessarily as an end state, i.e. as final conditions as opposed to initial conditions, but that in order to account for the momentary determinateness of experience, (i.e. the way the ball is rolling as opposed to the many ways in which it could roll, including rolling back to the apex) the future seems required to have a fixed and determinate character. So, it looks like the future, whatever it is, at least must be something that is both real, yet does not arise from indeterminateness. That looks like it contradicts the kind of triadicism described, which requires that all reality arise from indeterminateness. I presume some version of triadicism might try to insist that the future itself is also something arising from the evolution of determinate experienced moments. But that seems equivalent to saying that in the ball metaphor, the ball's rolling and only the ball's rolling actually determines the gravitional field, and so the gravitional field perforce loses its role in explaining how the ball actually does roll, and we are back to square one, why does the ball roll the way it does rather than just return instantly back to the indeterminateness of balance at the apex? Perhaps the triadic response would be to ask "How do you know it won't"? But that seems like avoiding the question rather than answering it, and also leaves me a little panicked insofar as it leaves open the continual possibility that all of what I am experiencing, and even my experiencing of it itself, is as likely to disappear as it is to continue developing.
Anyway, I hope at least I have made some sense to you of what my issues are with triadicism, and perhaps you will have some kind of response.

So triadicism in general is the idea that the relations between two things gives rise to a third, and that those three things do not have a reality independent of those relations? Probably a little simplistic, but if that is the gist of it, I suppose the tension for me here comes from the idea of giving rise, which looks like it might require independence of what gives rise and what is given rise to. But perhaps "giving rise" is not the right metaphor. Anyway, food for thought, thanks.:up:

No real project, just an interest in feasible alternatives to monisms and dualisms in the philosophy of mind.

Skim read the references, but I don't think it is quite what I'm after as to some extent the articles seem to be "preaching to the converted" insofar as it looks as if one already has to buy into a fully representational approach to the mind in order to appreciate the strength of their position. For instance, this from the short Friston piece:

if the
brain is making inferences about the causes of its sensations then it
must have a model of the causal relationships (connections) among
(hidden) states of the world that cause sensory input. It follows that
neuronal connections encode (model) causal connections that conspire
to produce sensory information.

It seems that the reader is supposed already to accept the antecedent of the initial conditional, and "inferences about" seems to be a representational notion, and the notion of "models" in the consequent certainly is. (Leaving aside the question about whether talk about brains making inferences is supposed to be taken literally or metaphorically.)
I might be wrong about this, of course: maybe the position does not stand or fall on the basis of a representational theory of mind. I appreciate also that the references you gave are overviews written with a somewhat sympathetic audience in mind. I think what would help clarify things for me is something on the philosophical foundations of this approach. You used the word "triadicism", is it to Pierce that one has to look, and if so, where?

:ok: Thanks.

the triadicism of a global systems viewpoint.

What would be a key text, or some key texts, for this approach please?

There is a distinction to be made between two claims. The first claim is that Hegel knowingly and rigidly attempted to apply a thesis/antithesis/synthesis dialectical method to every philosophical issue he thought about. That is very certainly false, you are correct, and is an error Stace makes for sure, but from memory I do not believe that McTaggart does and certainly more recent commentators like Houlgate definitely do not. Having said that, there is the different claim that the result of Hegel’s analysis in a given specific case fits the dialectical form thesis/antithesis/synthesis. For that claim, it does not matter whether one can find explicitly in Hegel a reference to that particular method, since it is an interpretative issue. The usual example brought forward by members of the thesis/antithesis/synthesis brigade is the Being/Nothing/Becoming analysis at the beginning of the Logic, but even there you have those like Houlgate who disagree. I do not stand on any particular side on that debate. All that having been said, the main idea behind my casual reference to the ideas of contradiction and synthesis in regards to thought and God was simply that an Hegelian analysis might show how any kind of opposition or tension between reason and religion, thought and God, could be resolved and Hegel scholars like Stephen Crites believe that it can, and in fact was resolved by Hegel.

VERY IMPORTANT: Thesis, Antithesis and Synthesis has nothing to do with Hegel's position.

Well, that seems a little too strident. English speaking idealist interpreters of Hegel such as McTaggart and Stace, different kinds of idealist admittedly, but no idiots either of them, find in Hegel's dialetic the "Thesis, Antithesis, Synthesis" model. It's not the be all and end all of his philosophy of course and those interpreters might be wrong, but it seems too involved an exegitical issue to just discard it out of hand as you do.
As for Hegel's theism, if it exists, we can certainly agree that it is very much more sophisticated than any acceptance of a revealed Christian religion, and for sure given his context he might have felt obliged to tow a Lutheran line in his everyday life even if he had no real Christian faith. The quotation I gave comes from his lectures on history, and in that work he takes revealed religion as simply a starting point.

Interesting that you quote Hegel. At least under some interpretations of Hegel, although he did not accept God as a being, and he had a conception of God far more sophisticated than any naive Abrahamic one, he nevertheless did think God was real, the apogee of reality in fact. Your "phantom deity" sounds a little like the God of positive revelation, which almost by definition is a concept hard for a rational mind to accept, but for Hegel it was probably just a starting point.
"This possibility to know God lays upon us the duty to do so..." Georg Wilhelm Friedrich Hegel
Perhaps for Hegel God and thought, although intially in apparent contradiction, become finally synthesised in Spirit?

A premise of my argument is that information content is propositional. This means, amongst perhaps other things, that if someone were to ask: "what is the information content encoded in such and such a physical state?", the answer to that question will require giving expression to a specific set of propositions. Specifying thusly that set of propositions is at least one wayto identify the information content of the physical state concerned. Another way of putting it is that the physical state has information content that is identifiable by specifying that set of propositions. This invites, but does not beg, a number of questions of course, including "What is a proposition?". An acceptably realist answer to that would perhaps be that propositions are sets of possible worlds. In any case, the point stands, if the only way my argument against physicalism can be rationally challenged is by delving into the complexities of such metaphysical questions as "What is content?", "What are propsitions?" etc, then it certainly avoids the equivocation objections that Churchland raised against Jackson's argument.

A true anecdote with most names eschewed to protect those innocent and still alive. Two respected but socially idiosyncratic Cambridge philosophers, who met at Wittgenstein's feet, ended up one day, to many of their colleagues astonishment, getting married. One of their colleagues is reported as saying: "I know X and Y just got married, I just don't believe it".
There are games in language in which "X but I don't believe X" make sense.

Your claim that "the only acceptable premise to add to an argument that is presented as a complete argument is a premise that is hidden" only applies if it is being claimed that the resulting argument is effectively the same as the original.

I thought I had been clear about this point, and here is a quotation from an earlier post of mine, emphasis added:
"One can circumvent objections by changing the argument, which is effectively what I did: it is certainly not Jackson's original argument." I have never claimed that my arguments are the same as the original argument, if by "original argument" you mean Jackson's. Thus my claim about what is acceptable to add to my last argument stands. However, on reflection there is at least one "hidden" premises in that argument, so please see a new version of it below and treat it on its own merits. The thing it shares with Jackson's argument is the intuition pump that Mary does learn something new about colour vision when she sees that tomato for the first time.

Regardless of how many ways this discursively-learnable information is the same as that encoded in the trunk's state, it is not identical to the latter information in at least three ways: 1) it is encoded as a physical state in the observer's brain, not a physical state of the trunk; 2) unlike the information in the trunk, it is the information content of someone's knowledge; 3) the trunk can be destroyed, while the observer continues to know something about its age when it fell.

None of this is relevant if we are assuming realism about information content, and most of what you talk about in your last post concerns how sentient beings might gain access to information content, but does not concern the what that content is in itself. Assuming realism about content allows the same content to be encoded in different ways. The points in the metaphysical premises of my argument concern identity of content conceived realistically, not identity of vehicle for that content. Nearly all of the points you make in your post concern differences in the vehicle for content and how different types of vehicle might come to encode the same content.

So, with my one concealed premise now exposed, here is the new argument against physicalism.

1 If physicalism is true, then everything anyone can know, in any sense of the term "know", about colour vision is physically encodeable.
2: All information content that is encodeable is identifiable by a finite set of propositions.
3: Any finite set of propositions is discursively learnable.
4: From 2 and 3; all information content that is encodeable is discursively learnable.
5: Anything that is physically encodeable is information content that is encodeable.
6: From 4 and 5 anything that is physically encodeable is discursively learnable.
7: At time t, Mary knows everything that is discursively learnable.
8: Mary gains new knowledge of some kind about colour vision when at t1 she sees a red thing for the first time.
9: From 6, if the new knowledge Mary gains at t1 is physically encodeable, then it is discursiveley learnable.
10: From 9 and 8, if the new knowledge Mary gains at t1 is discurvively learnable, then she did not know at t everything that is discursively learnable.
11: From 10 and 6, if the new Knowledge Mary gains at t1 is physically encodeable, then Mary did not know at t everything that is discursively learnable.
12: Since the consequent of 10 contradicts 7, by modus tollens what Mary learns is not physically encodeable.
13: From 1 and 12, physicalism is not true.

Note that if you now add your premise 0 to this argument, you get a deductively invalid argument. So, if you insist of creating an new argument by adding your premise 0 to the one above, your argument can be immediately rejected on the grounds that it is not deductively valid.


From what I gather, your issues with this argument focus on 2 and perhaps on 5. As indicated, everything you have thus far said against 5 conflates epistemological issues about how sentient creatures get access to information content, and metaphysical issues about information content itself. Do not misunderstand me, I am aware that realism about information content is a fraught issue. However, physicalism entails realism about information content, so if antirealism about information content is true, then physicalism is false anyway. So, for the purposes of arguing against physicalism it is perfectly acceptable to assume realism about content.

As a quick argument for premise 5, the very notion of encoding is that it is the conversion of data from one form to another, and data just is information content.

As concerns 2, I am not really appealing to authority. I am saying that it is a premise accepted or assumed by all physicalists and generally realist scientists and philosophers that deal with the notions of information, its encoding and its transference. Dennett and Churchland amongst them. However, there has been some recent work in philosophy that has attempted to make viable the notion of non propositional intentionality. If all intentional phenomena have content consisting entirely of information content, and not all intentional phenomena have content that is identifiable by propositions, then there will indeed be information content that is not identifiable by propositions, whatever "identifiable" means, and so premise 2 fails. However, if the objection to my argument is that there is non propositional intentionality, we are entering into very complex territory, and it is terrain that is very far from Churchland's fair equivocation points against Jackson's argument. If I have some spare time, I may well read a collection such as this Non Propositional Intentionality, but I feel I've said all I can or want to say about this for the moment.

As for your objection that this goes beyond your initial limited claims against Churchland's reply to Jackson, it would be inconsistent for you to do what you are doing - trying repeatedly to find an argument that holds up - while insisting that I must stick with only my first presentation of Churchland's argument (if the latter rule were applied consistently, there would be no debate about anything!) It would also be a contradiction to say that your latest argument is on-topic, while attempts to refute it are off-topic.

I did not make any such objection. I pointed out simply that the original aim was to provide an argument that circumvented Churchland's objections about equivocation of epistemological notions. The argument I present may not be sound, but it does not equivocate in the way that Jackson's original argument does. Thus Churchland's objections are, I claim, circumvented. This is done by introducing specific metaphysical claims about informational content that are absent from Jackson's argument, so it should not be a real surprise that Churchland's epistemological objections become otiose. I am also not insisting that you stick to your guns. Within the bounds of rationality, you are free to find fault points in my argument. There may even be equivocation going on somewhere within it, and perhaps even epistemological equivocation, but thus far you have not identified that equivocation.

you are in the corner of having not yet given a non- question-begging reply to the problem of why Mary was unable to learn it before t1.

Mary was unable to learn it before, because what she learns is not discursively learnable, and since everything that is physically encodeable is discursively learnable, according to the argument, what she learns is not physically encodeable either. So what does she learn? She learns what red things look like, and learning what red things look like is not discursively learnable. Of course; to be consistent I also have to say that what she learns is not identifiable by any finite set of propositions, so have I refuted myself by saying she learns what red things look like? Here I suppose we have to go Wittgensteinian and say that we do not identify what Mary learns with the expression "Mary learns what red things look like", but rather show or gesture at what she learns by doing so. The main point, in any case, is that whatever it is, it is not physically encodeable nor identifiable with any finite set of propositions.

The point is that you cannot simply reject the skeptic's assumption of the antithesis of your argument without begging the question.

But I am not simply rejecting it, I have presented an argument against it. Assuming the argument is deductively valid, which on the surface it is, the skeptic who wants to contest its soundness, and thus reject its conclusion, has a number of choices, whilst remaining rational. These include:
1: Show, by counterexample or some other means, that one or more of the explicit premises is false.
2: Show that there are hidden premises in the argument that are or might be false.
3: Linked to 2, show that there is an ambiguity in one or more of the premises and that when the ambiguity is clarified, the premises become false or at least possibly false.
4: Argue that we have more reason to reject the conclusion of the argument than we do to accept any of the premises.

4 would seem difficult to go for, after all physicalism and dualism are at least as much up for grabs as any of the premises of my argument. This leaves strategies 1 through to 3. Notice that I did not add.

5: Create a new argument by adding an entirely new premise to the existing ones that directly or implictly contradicts the arguments conclusion, thus turning the argument into a deductively invalid one. This is certainly a novel approach, but hardly a rational one.

Premise 4 is "Anything that is physically encodeable is information content that is encodeable." Given the context, I took "information content" to mean the information content of knowledge. If it is not that, then what is it the content of?

Information content can of course be the content of knowledge, but since realism about information content is being assumed, it need not be the content of any actual knowledge. A simple example, if we assume realism quite generally, there could well be a fallen tree in a forest somewhere that no one has seen, the trunk of which has 70 rings. That physical state, which we can describe in a finite set of propositions at whatever level of detail we like, has the information content that that particular tree had survived 70 seasons of growth. Note the the information content is here identified with a single proposition. There may be more information content than just this encoded in the phyiscal state of the tree, but there is at least this. One fine day, someone walks through the forest and comes across the fallen tree and counts the rings and forms the belief that that particular tree had survived 70 seasons of growth. Let's assume a version of physicalism and that that person is in a physical state that we can identify with her believing that that tree had survived 70 seasons of growth. That physical state is describable by a finite set of propositions, this just follows from the finitude of human beings. The information content of that state is the same as the information content physically encoded in the tree itself, i.e. the information content identifiable by the proposition that that tree had survived 70 seasons of growth. Is it now clear to you what I mean by information content and that it need not necessarily be the content of anyone's actual knowledge, and so objections to premise 4 need to be metaphysical in nature and not epistemological, unless you wish to challenge realism.

suppose we have some system having information on account of being in physical state ψ. if the corresponding propositions you have in mind are not a description of that state, then what are they? It is far from obvious that such propositions must exist, whether as a consequence of Shannon's information theory or of anything else. As things stand, proposition 1 lacks any justification.

I presume that the above talk about tree trunks makes it clear what the difference is between, on the one hand, the propositions that describe a phyiscal state which encodes some information content and, on the other, the propositions that describe the information content itself. As to the apparent issues you have with premise 1, it is in fact pretty much axiomatic for all theories of information content that I am aware of, that information content is identifiable by sets of propositions. It is certainly an assumption, not a consequence, of Shannon's theory of information transference, it is an assumption embedded in his free and undefined use of the term "message". It also runs through all of the philosophers who defend representational theories of mind, including physicalist representational theories of mind. It might be false, of course, but since it seems to be widely held amongst physicalists themselves, who are the target of the argument after all, I would like to see a counterexample or be referred to a relevant text where a physicalist non propositional account of information content is expounded. It might even be possible to come up with an actual argument that you could not have a coherent theory of informational content that allowed for content that was not identifable with finite sets of propositions, but on that particular point premise 1 is playing a card dealt to it by physicalists anyway, so I am content for the moment to sit on my laurels. However, if that is a point you want to pursue in detail, have at it.

There is nothing wrong with introducing a new premise into a discussion.

Certainly there is not. However, the only acceptable premise to add to an argument that is presented as a complete argument is a premise that is hidden. The premise 0 that you are offering is certainly NOT a hidden premise of my argument.
If I gave an argument such as:
1. If there is a pattern to the universe then a non finite sentient being exists.
2. God is the only non finite sentient being
3. There is a pattern to the universe.
Therefore God exists
and then you come along and add premise 0,
0: All sentient entities are non divine.
and then you point out that by adding in premise 0 to the argument, we can draw out a contradiction with 2, all you are doing is rejecting the conclusion of the argument but without pinpointing the premises of it that you actually reject.

Of course, you would not want to accept premise 0 in any argument, but that is beside the point,

It is entirely to the point, since the argument is presented as complete and with a conclusion that physicalism is false for colour vision. Your premise is effectively the claim that physicalism is true for colour vision. It is for you to show that the argument has hidden premises that can be objected to OR that there are explicit premises that can be objected to. It is no use just coming along with another premise that is effectively just a rejection of the conclusion.

You seem to be under the impression that I am implying that premise 7 must be false, but the point here is, instead, that if your argument, for the proposition that all knowledge having physically-encodable information is discursively-learnable, holds, then what non- question-begging reply do you have to the claim that Mary could have learned everything beforehand?

The argument requires not that Mary could have learned everything beforehand but that Mary could have learned everything physically encodeable because she can learn everything discursively learnable. The argument then adds a premise, 7, that she learns something new. If that premise is accepted, then it just follows from the other premises that what she learnsis not physically encodeable. There is no question begging going on.

There is alternative way of looking at your argument, by introducing premise 0: Everything that anyone could know about color vision is physically-encodable.

Let me deal with this first, I'll speak to the more significant issues you raise in your previous reply to me, concerning the notion of information content, in a later post.
First, by introducing a premise to an argument you do not look at an argument in an alternative way, you change the argument. The premise you wish to introduce, in this context, is effectively the claim that physicalism is true for colour vision. Why would anyone presenting an argument with the aim of proving precisely the opposite accept that their argument can be "looked at in a different way" by adding a claim they oppose?

and therefore premise 7 cannot be added to this argument without invalidating it.

As I have pointed out on a number of occasions throughout our discussion, the physicalist can object to the claim, expressed in premise 7 of my latest argument, that Mary learns anything new when she sees that red tomato. As far as I can see, all Jackson has on his side for motivating acceptance of it is intuition, and not in the Cartesian sense of that word, but the colloquial sense in which it is akin to something like inspired guess work. Is intuition in that sense a sound basis for support? Maybe in the end all we have to go on is intuition, but that is a metaphilosophical question. However, if a physicalist does want to reject premise 7, note that they are rejecting the argument for reasons other than those first put forward by Churchland and later expanded on by Crane etc. Those objections were based on the claim that Jackson was guilty of more or less subtle forms of equivocation, which may well be true. My final argument, however, has removed those equivocations. Right from the beginning, you may remember, my aim was to circumvent Churchlandish responses to Jackson's argument, whilst leaving something behind that at least retained the spirit of Jackson's argument. If, now, after amendment in the form of my latest argument, the physicalist is actually being pushed into the corner of rejecting the claim that Mary learns anything new, then that particular aim has been accomplished. My adapted argument also focuses the issues where, to my mind, they need to be focussed, which is on the theory of content that lies in the shared representationalist background of both the physicalist and dualist positions....which takes us to the points you make in your other reply, which I will reflect upon a little more before responding.

Actually, "could be stated" would be better as a synonym for "expressible". Sorry to split hairs, but there are nuances of difference between "can" and "could" that might make a difference in these kinds of debates.

At the risk of falling into a trap: no objections. :wink:

(especially given the distinction you made between 'expressible' and 'can be stated' in your previous post.)

That is not the distinction I made. Please reread the post.

Therefore, I do not accept this premise, though I will accept this:

You make it sound as though what preceded this sentence was an argument against premise one of my argument, but it was not. All you do is point out a pretty obvious, iterative distinction between a state and its description. That is not a counterexample to premise 1, nor any kind of reason to reject it. If you want to reject premise 1 you need to do better. Premise 1 seems perfectly in harmony with what you yourself referred to as canonical information theory.

Against premise 4 you state:

I cannot accept this, either, as only a small amount of all physically-encodable information is the information content of knowledge.

But that does not speak to premise 4 at all, within which there is no mention of knowledge, it is a metaphysical, not epistemological premise. The only epistemological premises of the argument are 6 and 7. Up to premise 4 all the issues are metaphysical. Note that the background assumption of the argument is a realism about information content, of course: i.e. there can be information content that is not the content of any actual mental state. But why would any physicalist object to such a realist assumption?

In summary, this argument fails because it equivocates between two different things: on the one hand, knowledge of the physical state encoding the information content of some other item of knowledge, and on the other hand, that other item of knowledge itself.

No it does not. You have misunderstood that premises 1 and 4 are metaphysical not epistemological in nature. Of course, if you want to discuss the possible collapse of that distinction, go at it, but it is probably not something a physicalist should attempt to do.

The claim that Mary learns something from seeing colors is a premise of Jackson's argument, and yours too, if I am not mistaken.

You are mistaken. My argument that you are referring to contained the conditional premise that if one accepts that Mary gains knowledge, then there is an obligation to say something substantive about what she gains. Jackson's argument states that Mary gains knowledge. But your misunderstanding on that point is a peripheral issue anyway, since we have now moved on to a different, and more fundamental, disagreement. Let's try a new argument:
1: All information content that is encodeable is expressable as a finite set of propositions.
2: Any finite set of propositions is discursively learnable.
3: From 1 and 2; all information content that is encodeable is discursively learnable.
4: Anything that is physically encodeable is information content that is encodeable.
5: From 3 and 4 anything that is physically encodeable is discursively learnable.
6: At time t, Mary knows everything that is discursively learnable.
7: Mary gains new knowledge when at t1 she sees a red thing for the first time.
8: From 5, if what Mary learns at t1 is physically encodeable, then it is discursiveley learnable.
9: From 8 and 7, if what Mary learns at t1 is discurvively learnable, then she did not know at t everything that is discursively learnable.
10: From 8 and 9, if what Mary learns at t1 is physically encodeable, then Mary did not know at t everything that is discursively learnable.
12: Since the consequent of 10 contradicts 6, by modus tollens what Mary learns is not physically encodeable.

The premises here are 1, 2, 4, 6 and 7.
Nothing you have said would lead me to think you would reject 2.
Your remarks about the notion of physical encodeability suggest to me you would also accept 4.
I'm not sure whether you accept 7 or not. You have not stated explicitly that you do, although many of your remarks seem geared up to defend physicalism even if 7 were true. Nevertheless, without explicitly accepting it, I am not going to force it upon you. As I have said a few times, the motivation for it is just an intuition pump.
I am also not clear whether you allow the possibility of premise 6 being true or not. It may be incoherent, although I do not see any obvious contradiction.
So, this leaves 1. Why accept 1? Well it is totally in accord with the information theory that Shannon developed. True, Shannon's original paper talks about the transmission of messages rather than content, but it is not a stretch to identify the term "information content" as used in the argument above with "message" as used by Shannon, and a message is very definitely something expressable in a finite set of propositions. Having said that, Shannon takes the notion of a message pretty much for granted.
Are there counterexamples to 1? Note that it is not a counterexample to point out that there might be people with contentful states that are pathologically unable to express that content. That some content cannot actually be expressed by a some specific individual in a set of propositions does not entail that the content is not expressible by such a set. In fact, if you tried to come up with a detailed counterexample of this type, it would probably be self stultifying, since you would have to identify, through propositions, what the content of the state was that the person was unable to express.
Might there be unecodeable information? Sounds like that might be a contradiction in terms, and in any case, it is not really a line a physicalist would want to push. Might there be information content not encodeable in a finite set of propositions? Well, transfinite information theory does not exist as far as I am aware, but that may be ignorance on my part.