What is Logic?

It seems to me that what we mean, when we say that some reasoning is logical, is that it is the kind of reasoning that would always, if we started with nothing but some truths, take us to nothing but truths. It is, for example, logical for me to deduce that you are a human from the (presumed) truth that everyone reading this is human, because if all the objects of a certain kind have a certain property, then any particular object of that kind will have that property. Why is that the case? Well, it just seems to be self-evident. I suppose that I could show the self-evidence by drawing a lot of red dots: given those dots, each of them is, of course, red (and each of them is a dot). Such reasoning is self-evident because it gives us just some of what we already had. Now, it seems to me that first-order logic is a mathematical model of such logical reasoning, which is about things (subjects) and their properties (predicates). In short, I take predicate logic to be linguistic, and first-order logic to be mathematical. But I am beginning to wonder if I have got this all wrong, because I found the following description of predicate logic on a paper in a book in the library:

Predicate logic (first-order logic) is a formal system that extends propositional logic by breaking sentences down into subjects, predicates (properties), and quantifiers. It enables precise reasoning about objects by defining properties and relationships, allowing for statements like "all dogs are blue", which propositional logic cannot express.

Travels = Travails

I'm Back in England for the Summer (except for Aberdeen next month) but all I'm doing is rewriting my response to Mawson and having deep thoughts... News Flash: I'll be hosting the best Carnival in the world wide web next month too (it needs doing hint hint and it's fun to play god :)

Is there a question?

Is it the job of analytic metaphysicians, to put back the pictures that the axiomatic mathematicians remove from our scientific descriptions of reality; and if not, why not?

Limerick

There once was a man from Limerick
Who got, in his weakest limb, a wrick;
His eyes filled with glints
As he spied, of splints
Split from a tree's limb, a rick.

Stuff (and this and that)

Kripke (Naming and Necessity) described how "water" means H2O because people once indicated the liquid form of H2O and said something like "that stuff," so that (via a causal chain) we now mean by "water" what they meant by it. But if so, then had some weird spacetime wormhole (or something) substituted that bit of water for XYZ briefly, just before they said "that stuff," then we would have been misusing "water" ever since (and obviously we have not, whereas it's not so obvious that such a substitution could not have been).
......Furthermore their folk metaphysics may not have been much like ours, way back then (instead of our chemistry, something like alchemy maybe), so why would "that stuff" have meant H2O then? Indeed, what stops us referring, with our "water," to H2O in any of its fluid phases (the liquid phase is largely H+ and OH- ions anyway), or to any similar mixture of hydrogen and oxygen (similarly) or of nucleons and electrons, or to just the oxygen or just the nucleons, or (conversely) to impurities in the water as well as the H2O (as we may well do ordinarily), and so on?
......Presumably we all presume some (similar) folky metaphysics, so that our "that"s are intimately (if subconsciously) associated with something like a description (if an indescribable one) in our heads. Furthermore, once we've separated out such descriptivistic content, there might not be anything externalistic left over.
......Even if the reference of "water" is fixed from day to day, by our thinking "that stuff" while thinking of some actual water, the substance underlying H2O might be a different one on different days (e.g. as subatomic strings randomly pointed in different directions, or something), and we would not then mean, by "water," different substances on different days. If the underlying variation made no observable difference, it would be like there was (as presumably there is) no variation; the stuff referred to would be the constant chemical (defined by its chemical description, and hence via the meaning of "chemical"). And if it did make a difference then descriptivistic content would again determine which stuff we were referring to (cf. normal versus heavy water).
......Furthermore, while there may seem to be an externalistic element with the "that" of "that stuff," there would surely be (after all the descriptivisitic stuff) an internalistic "this," because only a reference to this Actuality (containing both that stuff and us) would be able to lack descriptivistic content.
......There is therefore (for a frivolous consequence) surprisingly little incoherence between Biblical literalism and modern science; e.g. when originally creating water (not just below but also above the starry firmament) God would have had some description (some range of relational roles or whatever) in mind, but such details as the underlying substances (e.g. the particles that comprise the H and the O nowadays) might quite naturally have varied as the more crucial (e.g. moral and psychological) matters were settled.

Form is the diagram of forces

                       Dark incarnate hearts
pump hard as rooks heave at dusk,
wing-beats glistening.