I've been thinking about conventions. In particular about implicit and explicit forms of conventionalism. A lot of folk seem to think that the whole conventionalism about modality jig was up when Quine decided he didn't like it. Shortly after he decided this, he also decided to say that it was wrong. Now, I have this running joke that Quine is the smartest philosopher to be wrong about everything, and whilst this is meant to be taken light heartedly, it's unfortunate that 'Truth by Convention' lends weight to my facetious condemnation. Whilst he may not be wrong that conventionalism is wrong (my own personal jury (of whom I'm sure you're both eagerly awaiting the verdict) is still out on that one), I'm pretty confident that if it is wrong, it's not for the reasons that Quine gives there.
What Quine says is (broadly) this. The linguistic doctrine of necessity, if understood in terms of convention, can take one of two forms. One is a formal system of explicit conventions that stipulate the truth of claims of certain forms. The other is to talk about implicit conventions, but Quine refuses to understand this, saying that it is simply adding a layer of metaphor to an otherwise already mysterious doctrine. Quine then goes on to say that the explicit formal system approach is inadequate because it leads to a vicious regress that prevents one from securing all of the necessary truths that we think there are. This, combined with his dismissal of implicit conventionalism, leaves Quine in a position to reject conventionalism.
Well, fair play to him. He was writing in 1936 and the silliness of implicit convention was a pretty widely accepted position, so you can't really blame 'ole Willy-van. However, we are fortunate enough to live in a post Lewis world where the notion of implicit convention is regarded in better light than silly things.
However, the advent of the acceptability (or at least potential acceptability, let's not jump the gun here) of implicit convention leaves us with an obvious conundrum. Where does the distinction between explicit and implicit lie? The easiest way to think of implicit convention to my mind is just to say convention that isn't explicit. I know that's a bit lazy, but there you go. It's nice and flexible, and captures my intuitions well enough. Any variation in how one interprets the difference should go on the explicit side. So what is it for a convention to be explicit? Well, that's a bit trickier. Here are some (increasingly weak) ideas:
1 - Audible, public, verbal/written agreement:- We're playing a board game and decide it's not hard enough, so we agree that whenever you role a one on the dice you have to go back a space.
2 - Rules that can be formalised or expressed by specific sentences:- Even if we never publicly agreed to shake hands when we meet new people, we could (if we wanted to) say "when you meet new people, it is polite to shake their hand" or the imperative "when you meet new people, shake their hand".
3 - Rules that we can be explicitly aware of:- It's not clear to me that this would be extensionaly different from 2, but it at least seems to me to be intensionally (or at the very least hyper-intensionally) different.
I haven't thought of others yet, but there probably are. The particular problem I find is that none of these seem like particularly natural definitions. Maybe I'm missing some really obvious candidate, but to me 1 looks too strict, and 2 looks too weak (and so 3 also). I'm not sure where to stand on this yet. Perhaps I have approached it from the wrong angle after all, and I should be looking for a definition to match my intuitions about what it is for a convention to be implicit. But, meh. I still don't like the taste of that. Maybe I just need to get a grip and chose one, and accept that it may not matter much. There are also other issues like the amount of freedom one has with regard to the formation of conventions, but I don't think this is directly linked to whether they're explicit or not.
I have choices to make if I'm to go ahead with forming a taxonomy of conventionalist positions on essence. I eagerly await being able to write on an implicit and expressive conventionalism which (thanks to Schmomas) I'll be calling 'impressive conventionalism'.