...continued.

Having (I hope) clarified these matters, let's move on to the argument as set out in your numbered sections:

A thought can be right or wrong, but right-ness implies likeness to reality, while wrong-ness implies un-likeness. To illustrate: suppose Bob has a thought about a tree. Let's say it's "this oak tree is made of wood". Now suppose his friend Bill thinks "this oak tree is made of copper". I take it we can premise that Bob is right and Bill is wrong. But for our premise to be true, their thoughts must be compared to the tree itself. There is no other way to judge their thoughts' right-ness or wrong-ness."

The last sentence here is the first occasion in your latest post where you make a sweeping claim without offering any justification for it to be accepted. When you construct an argument, you can use, as a premise, any statement that is in the form of a proposition, but for it to be a sound argument, you have to show that it is a fact, and in epistemology and elsewhere, the generally-accepted basis for regarding a premise as being factual is the JTB criterion: it states a justified, true belief. Your say-so does not amount to either verification of the claim as being factual or justification for thinking it is.

The first problem in attempting to verify this premise is that you have not given the slightest explanation of what it means to say a thought is like reality. What would it mean to say that Bob's thought of an oak tree is like an actual oak tree? Does it grow from an acorn? Does it have the genetic signature that is shared by oak trees? These are both facts about them that might be the content of thoughts - indeed, they are right now, as you read this!

It gets even more problematic when we move on to a broader range of propositions. Take the claim "the highest mountain in the world is in Asia." In what sense does this thought have the property of being in Asia? Alternatively, if it does not actually have this property, then what does it mean to say this thought has a relevant likeness to the facts of the matter? When I learned the other day that Phil Lesh had died, was there something dead about my thought? Or there is this: "beta decay produces neutrinos." Does the neutrino component of this thought respond to the weak force? Furthermore, there was a time when neutrinos were postulated but had not yet been discovered - and then, when it was, did thoughts about neutrinos suddenly gain a likeness to neutrinos themselves?

What's more, Bob's thought about oak trees, as you have presented it, is a sentence, rather than an ineffable feeling that an oak tree is made of wood - i.e., it is a sequence of words conforming to a grammar. Do the words "tree" and "wood" have a likeness to the things they denote? One can easily doubt it on the grounds that words seem to be arbitrary: except for the relatively few onomatopoeia (and not strongly even then), it seems that words are not constrained to be in any way like the reality they express: for example, when physicists named the charm quark, were they obliged to pick the word 'charm' in order to ensure that propositions containing it had the necessary likeness to reality? Of course not! The problem for you here is multiplied by the fact that there are a great many different languages, with wildly varying sounds at the level of both words and grammars, yet despite all this, we obviously are not in the situation you claim would come to pass if your thesis fails: we have not lost the possibility of rightness, and all thought has not become meaningless.

Perhaps you think that this likeness is not to be found in individual words, but only in propositions as a whole - but this does not do away with the need to explain how this likeness comes about. Furthermore, this position is, ipso facto, one in which the likeness is emergent, so, in constructing an explanation along these lines, you will have to overcome your struggles with the concept of emergence and embrace it.

There are other claims in the first section that are moot in the light of the clarifications above, so there is no need for me to address them here. This also applies to quite a few statements in section 2, but there are a few that give pause. For example, I am curious as to what you suppose follows from your statement that "A brain state is one result of a particular causal chain, but there is nothing special about it on that account." What does being special have anything to do with whether it might be part of an answer to our central question? I can see that things like falsifiability and consistency matter, but being special...? In fact, not being special seems to me to be a virtue: the chain-of-causality story is straightforward, has clear premises, does not require the acceptance of propositions for which no justification is given, and does not stray far from uncontroversial facts about minds and communication.

I believe your objection "more specifically, a causal chain cannot in itself be 'right' or 'wrong'. It is possible that a causal chain will cause Bob to think a tree is made of wood, and cause Bill to think it's made of copper. This is not enough for Bob to be right and Bill wrong, because the chain has no connection to correct-ness." has been thoroughly addressed above: in short, it is the flow of information originating in the real world that makes it possible for thoughts about the real world to be correct.

You go on to say "It can't give us reason for saying "Bob's thoughts are like reality, and Bill's are not"."My first response to that is until you can say what the similarity is between Bob's thought and reality, and give us a decision procedure by which we can tell that Bob's thought is similar to reality while Bill's is not, then even if we accepted your thesis, we would still not have a reason for saying "Bob's thoughts are like reality, and Bill's are not", because we would not have enough information to make the call.

I propose that the way we get a reason for deciding whether a proposition is realistic is that we make use of information flowing on the chain of causality to draw our own conclusions. I get the impression that you feel this is not good enough, but the thing is we are in no better position than are Bob and Bill: the best we can do is to make the call on the basis of what we already believe to be true, or what we come to believe is true as a result of investigations into what information we have, whether it can reasonably be regarded as factual, what other information might be available and what effect it could have on our decision (for example, we might initially side with Bill, but change our minds after Bob explains to us why he thinks the rock is just pyrite. This is another example of a causal chain bringing about true thoughts, and it is, roughly speaking, the sort of process that Bayesian reasoning seeks to formalize.)

The truth of any proposition about reality is not determined by whether or how we can determine that it is correct; it is either true or false from the get-go. The Collatz conjecture, for example, is either true or false now, and has been at least since it was first conceived of (mathematical Platonists presumably think it has always been either true or false) - the problem is just that we do not know which it is.

There is no oracle that reliably sorts all propositions into true or false buckets; Gödel, Turing et.al. hammered the nails into that coffin, and it is obvious that we don't need an oracle in order to avoid the dire situation you claim would follow from your thesis being false (plus, if this oracle was an essential tool in making sense of the world, it would already have been used to find out if the Collatz and other conjectures are true or false.) It is not, therefore, a problem for chain-of-causality that it cannot do so, and if you think it is, it would be inconsistent for you to assert that it is not also a problem for your thesis.

continued...