I've done some thinking about this, for CFJ 1730 and since then, and
it seems to me that action announcements clearly have a truth value in
the normal manner. They are grammatically ordinary statements, in the
indicative mood and the present tense. The only thing that distinguishes
them from other statements is that the rules attach additional semantics
to them. Rule 478 says:
A player performs an action "by announcement" by announcing that
e performs it.
So for a player to perform such an action, e must announce that e is
doing so. This is in all other respects an ordinary announcement,
and in particular it is a statement that is either true or false.
Of course, the statement is (usually) true only because R478 makes
it self-fulfilling. If the word "hereby" is included, this narrows
the statement so that it *only* covers the self-fulfilling situation,
but does not make it anything other than a statement.
If I attempt to act by announcement but the action is impossible, then I
make a false statement. For example, if I say "I spend a pink VC and an
infrared VC to increase Wooble's VVLOP by 1.", this is a statement about
a conceivable action. If I actually have no pink VCs then I can't, and
therefore don't, spend any. In that situation the statement is false,
because (contrary to my claim) I did not spend a pink VC. The fact that
in some other circumstances the statement could have been self-fulfilling
does not deprive it of a truth value in this situation.
Consider also an attempt to act by announcement where the rules don't
ever make the action possible. If I say "I set Wooble's VVLOP to 3.",
this is simply a false statement. On the other hand, "I post an email
message." is simply a true statement, even though its truth does not
derive from the rules.
Michael suggests that we could equally well take game actions by messages
that do not take the form of statements. For example, the rules could
state that a vote is submitted by sending a message containing the
magic word "ABULAFIA" followed by a proposal number and a vote value.
In this case, being a non-statement, the message would indeed not have a
truth value. But that is not what the rules say, and it is specious to
argue that the present rules are equivalent to that in all aspects just
because of an equivalence in some aspects. The rules actually say that
a vote is submitted by means of a public statement that one is casting
a vote. In the situation actually at hand, therefore, messages that
achieve voting (or attempt to) are necessarily also statements of fact
and have truth values.
-zefram
