What do we mean when we say that something is true by definition, or that this kind of truth is not contingent?
If we take Rome or Sparta as examples, then the truth of the definition is historically dependent. Sparta may always have been "Hellenic" in opposition to bar-barians, but it was not always a part of Greece (in the sense of a modern state). When Romulus and Remus established Rome (Ab urbe condita, 753 BC), it was as a city-state at most, and it would make no sense at that time to say it was the capital of Italy (the Sabines would have made a very strong protest).
Definitions obviously change with time, so something is true by definition when the definition itself is true, and if the meanings of words are contingent, one presumes that whether or not something is true by definition is equally so.
Yes, of course, whether a truth is true by definition is a contingent matter. But that does not mean that there are no truths by definition. (I don't know whether you think that there are no truths by definiton, though).
---------- Post added 02-26-2010 at 10:39 AM ----------
You're confusing things. Reconstructo posted a good article on the analytic and synthetic distinction.
Here's an easy way, according to Kant, to show you are wrong:
The concept "Italian" is not contained within the concept "Roman". Therefore "Every Roman is an Italian" is a synthetic proposition. Also, not all Italians are Roman (someone could be Sicilian, for instance). Something like, "All bachelors are unmarried men" would be an analytic proposition, true by definition. All unmarried men are bachelors, and all bachelors are unmarried men.
Trouble is that "contains" is a metaphor, and it is no clearer than what it is meant to explain. Is "unmarried" contained
in "bachelors"? Search me.
He did not say that all Italians are Romans. He said that all Romans are Italians. Of course, a German may be a Roman, but not be Italian.
It might very well be that all Romans are Italians. The question at hand is not that, but whether necessarily
, all Romans are Italians. Whether is is impossible
for X to be a Roman and not an Italian. It might be true that all X is Y, but not necessarily
true that all X is Y. If all X is Y is analytic, it has to be necessarily true, not just true.