Here. UPDATE March 2013: This document has been completely superseded by An Account of Subjunctive Necessity.
Email comments or questions of any kind to tristanhaze (at) gmail (dot com), or post them here.
I would appreciate any feedback, no matter how minimal or unlikely to be helpful you think it is. (For example, let me know if something didn't make sense to you, or just seemed wrong.) I'm very keen to improve the presentation of these ideas, as well as the ideas themselves.
This is an early draft, and many of my current formulations are probably inadequate.
The paper is written for a fairly specialized audience. I intend to give a more thorough and accessible treatment of these ideas in a projected book. Its working title is Necessity and Conceptual Systems.
The overall aim is to draw connections between modal concepts and broadly semantic concepts (the latter including the notion of a conceptual system). The basic idea is that necessarily true propositions are in some sense invariant through all configurations of the systems they belong to. (This is squared with the view that not all necessary truths can be known a priori by means of the notion of an empirically defeasible concept-formation.)