On Future-Tense “Propositions” and “Truth-Value”
Posted: 24 March 2010 12:03 AM   [ Ignore ]
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I was reading the page on “truth” on the IEP and had a quick thought:

From the Internet Encyclopedia of Philosophy (IEP): http://www.iep.utm.edu/truth/#H3

2. Predictions of future events

What about declarative sentences that refer to events in the future? For example, does the sentence “There will be a sea battle tomorrow” express a proposition? Presumably, today we do not know whether there will be such a battle. Because of this, some philosophers (including Aristotle who toyed with the idea) have argued that the sentence, at the present moment, does not express anything that is now either true or false. Another, perhaps more powerful, motivation for adopting this view is the belief that if sentences involving future human actions were to express propositions, i.e., were to express something that is now true or false, then humans would be determined to perform those actions and so humans would have no free will. To defend free will, these philosophers have argued, we must deny truth-values to predictions.

This complicating restriction – that sentences about the future do not now express anything true or false – has been attacked by Quine and others. These critics argue that the restriction upsets the logic we use to reason with such predictions. For example, here is a deductively valid argument involving predictions:

We’ve learned there will be a run on the bank tomorrow.
If there will be a run on the bank tomorrow, then the CEO should be awakened.
So, the CEO should be awakened.

Without assertions in this argument having truth-values, regardless of whether we know those values, we could not assess the argument using the canons of deductive validity and invalidity. We would have to say – contrary to deeply-rooted philosophical intuitions – that it is not really an argument at all. (For another sort of rebuttal to the claim that propositions about the future cannot be true prior to the occurrence of the events described, see Logical Determinism.)

~Assuming the idea of “propositions” is valid:
Future-tense propositions such as “There will be a sea battle tomorrow” (let’s call it P1) have implicit claims/propositions supporting them, allowing them to make any sense. Those presupposing claims are what allows us to identify future propositions as having “truth-value” or not. For instance, to say P1 as a result of attending a confrontational meeting between 2 battle ship captains is to implicitly state:
-“The person (making the claim) attended a threatening confrontation between two people in charge of two battle ships.
-The two captains agreed to do battle at a specific time “tomorrow” (ie a specific date)
-They both have track records of doing exactly what they say in such situations
-They have sufficient motive to commit to their actions.
-They have the means to follow through on their threats
-Inductive logic is a valid or justified process
-etc

In contrast, the statement P1 is NOT to say:
-The person making the claim has the ability to predict the future
-That person knows due to that ability the battle “will take place.”

So the proposition can have truth-value depending upon the actual premises used to support the proposition. We see here that 2+ propositions with the exact wording can have two or more different meanings behind it. It’s on the basis of the underlying suppositions that gives the proper context for the proposition and allows us to recognize truth-values or a lack thereof in such declarative sentences.

Now arguably, one can “reduce” back far enough to where clarity and definition can be obscured to question whether any word can be so reliable in the use of structuring any proposition to have truth-value whatsoever. This is however a separate issue. The argument that I’m calling into question already supposes that certain “propositions” can possess “truth-value.”

Regarding the free will objection, I think it can be argued that any presuppositions supporting a given future-tense proposition are making claims about what are “justifiably acceptable inferences of understanding” rather than a necessary outcome of the future. This type of use of language can probably be attributed to the need or want of expediency or convenience in communication. This wouldn’t necessarily take any “side” on the free will debates. I can elaborate on that if necessary.

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Posted: 25 March 2011 01:08 AM   [ Ignore ]   [ # 1 ]
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Kaizen - 24 March 2010 12:03 AM

In contrast, the statement P1 is NOT to say:
-The person making the claim has the ability to predict the future
-That person knows due to that ability the battle “will take place.”

Just a nitpick, but by stating a claim like “there will be a sea battle tomorrow” is predicting the future. I think what you mean to say is that the person making the claim has the ability to inerrently predict the future. Predictions by themselves can be right or wrong, but still be predictions.

Otherwise, makes sense to me. It seems to sometimes be easy to make philosophical musings based on elements of language that are imprecise, thus creating a confusion between a logical problem and a linguistic one. This “sea battle” sentence in question, to me, is more of a linguistic problem than a purely logical one, precisely because of what you bring up: we have to address the assumptions that went into the statement, and the statement itself is also inherently vague. For starters, what kind of a sea battle is going to happen? It could be anything from a clash between armadas to a shark eating a tuna.

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