For the old age of the world is to be accounted the true antiquity; and this is the attribute of our own times, not of that earlier age of the world in which the ancients lived, and which, though in respect of us it was the elder, yet in respect of the world it was the younger.
The metaphysical thesis of physicalism, according to Jackson, can be defined as follows: any possible world that is a minimal physical duplicate of our world is a duplicate simpliciter of our world.
Correspondingly, it is epistemically possible that our world is the XYZ-world (or at least, that it is qualitatively just like the XYZ-world).
We can represent this structure diagramatically as follows: H2O-world XYZ-world H2O-world H2O H2O .
This remark would have a point only if it said something that was false in possible world x, since what one is trying to do in making the remark is to tell one's interlocutor that the actual world is not a world like x.
The value of the primary intension for a given centered world as argument is defined to be the same as the value of the two-dimensional intension for the pair of arguments consisting of the centered world and the same world, uncentered.
I find it useful to characterize beliefs as having the mind-to-world direction of fit (the belief in the mind is supposed to fit the state of affairs in the world) and desires and intentions as having the world-to-mind direction of fit (if all goes well with the desires and intentions, the world comes to fit how it is represented in the mind).
The intension of a general term maps a possible world to the class of individuals that fall under the term in that world: the intension of 'cat' maps a possible world to the class of cats in that world.
There is surely a possible world in which the word (or at least one orthographically like it) has such a meaning, and there is a two-dimensional intension that takes the actual world into the actual meaning of 'coumarone' and this counterfactual world into the meaning that it has there.
There is hardly a climate or condition in the Old World which cannot be paralleled in the New—at least as closely as the same species generally require; for it is a most rare case to find a group of organisms confined to any small spot, having conditions peculiar in only a slight degree; for instance, small areas in the Old World could be pointed out hotter than any in the New World, yet these are not inhabited by a peculiar fauna or flora.