- Why do you think dialetheism relates to the consequence relation? Presumably you think the LEM is tied to the consequence relation, and that dialetheism therefore interferes with it, but I'm not sure you have given an argument in that vein.

But I don't really intend to continue this conversation about dialetheism, especially given my earlier demonstrations of the incoherence of the "Liar's paradox." From what I have seen, people are dialetheists for the same reason they dye their hair purple. :grin:

I'm thinking this (very consistent!) holding onto the LNC is a part of why these developments have taken so long to be achieved.

Perhaps partly, but I think the other big factor would be that it is not actually easy to remove LNC and not end up with triviality. You seem to have to get rid of disjunctive syllogism, reductio arguments, or disjunctive introduction, and on many early attempts to understand this, all three.

But these all make sense, e.g. disjunctive syllogism intuitively seems right, so if a contradiction lets us prove anything from it, the contradiction seems to be the problem.

So even if people further back in history wanted to remove it, they couldn't without making everything true.

For my part I think the metaphysics of truth ought to be set to the side for purposes of the question -- I'd say if our metaphysics of truth can't accommodate our logic then it's our metaphysics that are in error.

First part, I'd agree, although I think it will end up being relevant if arguments for nihilism (or a pluralism bordering on nihilism) are made from the assumption of relativism and deflation re truth (which I suppose are metaphysical positions of a sort, but can be presented as "anti-metaphysical"). However, I don't think one needs any sort of in-depth metaphysical theory to say, "good reasoning has something to do with leading to truth and logic is meant to model/enhance good reasoning." Normally, the move to define "correct logics" in terms of natural language, or in the more common sense formulation of "good reasoning" seems like a way to get at this without having to make any metaphysical commitments. Normative views of logic accomplish the same thing. I just think that if we interrogate the normative views, we end up finding some notion of truth further back (maybe not, it's irrelevant to the pluralism debate anyhow).

The second part doesn't make sense to me. On this view, if we accept using truth in a model as truth for pragmatic purposes in logic we should dismiss non-relative truth in metaphysics. But I don't see how there is any connection here. The first move is a pragmatic bracketing of a thorny question, not producing an answer to that question.

It seems to me logic is a bit like math (while not being reducible to math) in the way that it can be developed or "discovered".

Yup, which is why I imagine they have very similar sorts of debates.

Anyhow, it seems possible to both affirm and deny pluralism/monism in the terms laid out without contradiction, since there is equivocation in the "subject matter of logic." I don't think it's particularly implausible to say something like:

"If you are interested in logic primarily as an abstract formal system, there are no correct logics, but there are uninteresting ones. (A sort of nihilism). If you are interested in logic as good reasoning this answer is less obvious, but there are clearly many incorrect logics, since it is not good reasoning to affirm everything, almost everything, or almost nothing."

I think a difficulty, even in published articles, is equivocating on just this issue relative to one's opponents. It's one thing to disagree with how they define the subject matter of logic, but obviously another to use arguments based on one such definition to attempt to refute a position based on another.

Early in this thread I mentioned the older distinction between formal and material logic. This distinction is similar, although not identical, to claims that consequence might vary by domain. I think the furthest advances in material logic in Poinsot, CSP, etc. do offer at least a plausible explanation of why exactly consequence might vary when we move to consider signs (which of course introduce self-reference), particularly stipulated signs systems. This is relevant if the very point in question is if logic is about reasoning by beings or about stipulated sign relations.

Whereas if one conceives signs from the post-modern perspective that grew out of Sausser then it might seem obvious that formal relations are the only thing to consider. So, one could frame the debate in terms of the proper understanding of signs I think, and probably argue towards either position depending on how one understands signification.