In yesterday’s
post, I showed that if an open-futurist is impressed by a certain
plausible-sounding logical fatalism argument based on bivalence, and
hence opts for truth gaps, then they should also be impressed by
another logical fatalism argument based not on bivalence but on truth
gaps.
However, there was a weakness to my logical fatalism argument. It was
based on the principle:
- If something true now is incompatible with it’s being true that p,
then p is not within your power.
But perhaps our open futurist will deny (1) on the grounds that a
present action can be within our power, even though it is
presently true that we will do it. (I think this is a problematic
concession for the open futurist to make, but let’s bracket that.) Such
an open futurist will instead run arguments based on:
- If q is a past-tensed
truth, and q is incompatible
with p, then p is not within your power.
Well, here is perhaps a truth value gap counterexample to (2).
(To get the second part, we can suppose that the laws of nature are
such that they only allow indeterministic events after 4:30 pm each day,
or maybe God just promises not to allow any indeterministic events
between 2 and 4 pm.)
So, consider the following complicated past-tensed statement, which
is true at 3 pm:
- q: Two hours ago [i.e., at
1 pm], it was true that no indeterministic events would happen between
an hour ago [2 pm] and an hour from now [4 pm], while half an hour ago
[2:30 pm], it was neither true nor false that Alice freely ϕs at 5 pm.
Now, on the open futurist’s view, time-indexed propositions can only
gain truth value as the result of indeterministic events. It logically
follows from the ban on indeterministic events between 2 and 4 pm that
any time-indexed proposition that was neither true nor false at 2:30, is
also neither true nor false at 3 pm. Or to put it in a tensed way, q entails:
- It is neither true nor false that Alice ϕs at 5 pm.
But (3) is logically incompatible with Alice ϕing at 5 pm, since, necessarily, if
Alice ϕs at 5 pm, then it’s
true that Alice ϕs at 5 pm.
Since q entails (3), it
follows that:
- q is logically
incompatible with Alice ϕing
at 5 pm.
Hence it follows from (2) (since q is a past tensed truth) that at 3
pm it is true to say:
- It is not within Alice’s power that Alice ϕs at 5 pm.
Now, I said that “perhaps” this was a counterexample to (2). Besides
objecting to the Tarski T-schema, there is one powerful response an open
futurist can make. They can just embrace (5) and say: it’s only at 5 pm,
or shortly prior to it, that it comes to be within Alice’s power to
ϕ.
But I think the open futurist’s intuitions behind (2) also
support:
- If q is a past-tensed
truth and p is time-indexed,
and q is incompatible with
p, then p will never be within your
power.
(The reason for the restriction to time-indexed p is to avoid this counterexample.
Let q be the proposition that
there was no wine in the world a minute ago. Let p be the proposition that you are
drinking well-aged wine. Then p and q are incompatible. But if you make
wine, and age it, then it can come to be the case that drinking
well-aged wine is in your power.)
And now (4) and (6) imply:
- It will never be within Alice’s power that Alice ϕs at 5 pm,
which is just false in our story, since she does ϕ at 5 pm! (Alternate phrasing:
replace “within Alice’s power” with “up to Alice”.)
What about open futurists who instead of supposing a truth value gap
think that statements about contingent future events are all false? Well, such
open futurists will not accept q (at 3 pm). But they will
accept:
- q′: Two hours ago [i.e.,
at 1 pm], it was true that no indeterministic events would happen
between an hour ago [2 pm] and an hour from now [4 pm], while half an
hour ago [2:30 pm], it was false that Alice freely ϕs at 5 pm.
Again, on their view, time-indexed propositions only change truth
value when indeterministic events happen. Thus, q′ entails that presently (i.e., at
3 pm) it is still false that Alice freely ϕs at 5 pm. And the rest of my
argument goes through.
So it pretty much seems like I’ve shown that the only person who can
accept a principle like (6) is someone who doesn’t believe in the
possibility of free will.
Maybe what this is really an argument for is that the open futurist
needs to deny the T-schema, which I had used to argue that if something
is incompatible with it’s being true that Alice will ϕ at 5 pm, then it’s incompatible
with Alice ϕing at 5 pm. Some
open futurists do do that (Keith DeRose, for instance; I wonder now: do
they do it because of an argument like this one?)
I have to confess a nagging suspicion of an error somewhere. I
already found one that I just corrected—I had to restrict (6) to
time-indexed truths, which forced me to remove an argument that would
work even without the T-schema.