If everyone died, would Kansas still exist? Or does Kansas have to have someone recognizing it to exist?

The land mass that we call "Kansas" would still exist (unless, of course, the reason that everyone died was that the entire Earth blew up, or something like that). But Kansas the state is a "socially constructed" object (of the sort discussed by John Searle in his book The Construction of Social Reality) and would thus no longer exist. On the other hand, there might still be books and maps that refer to that land area as "Kansas", so extraterrestrials visiting Earth later on (or Earth animals that evolve to replace humans as intelligent residents of a future Earth) might be able to refer to it that way. Most artifacts are like this: The substance they are made of is human- or mind-independent; the use made of them is not---so, a flat tree stump would still be a flat tree stump after all humans die, but if it had been used as a table by some human, it would no longer be a table.

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