speakers and hearers; the state of the external world makes a contribution as well. Thus, two speakers could be molecule-for-molecule duplicates and yet mean different things by their words. 46 Reference and referring Possible worlds I shall now set up the apparatus needed to state Kripke's fundamental criti- cism of description theories of proper names. I begin with the notion of a "possible world." (It goes back at least to Leibniz, though it was incorpo- rated into philosophical logic only in the twentieth century.) Consider the world we live in--not just the planet Earth, but the whole universe. Our talk about things in our universe is talk about what actually exists, what things there really are: Gordon Brown the British Prime Minister, my left elbow, Bolivia, the sandwich on your plate, the Andromeda Galaxy, and so on, but not Hamlet, the Easter Bunny, the Big Rock Candy Mountain, or the free lunch
256 Chapter 13 polyethylene (LDPE) and high-density poly- dation in beef, leading to the enhanced ethylene (HDPE) films has been studied in display life of the meat. Additionally, Camo food systems. In such systems, release rates et al. (2008) investigated and compared the and migration amounts must be closely mon- effect of two natural antioxidant sources itored for the system to effectively preserve (rosemary and oregano extracts) incorpo- the contents of the package (Han 2000). rated into an active package filled with a Looking to the consumers’ demand for modified atmosphere on the display life of chemical preservative-free foods, food man- lamb steaks. These workers found that a rose- ufacturers are now using naturally occurring mary extract, a rosemary active film, or an antimicrobials to sterilize and/or extend oregano active film resulted in enhanced oxi-
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