Saturday, December 03, 2011

The insoluble problem of future tense statements

Vallicella finally addresses the problem of Excluded Middle and Future-Tensed Sentences.  A prediction in 1996 that the FTSE would reach 10,000 by 2011 would have been wrong at the time the prediction was made.  As he points out (using the US Dow index as his example), subsequent events merely made it evident that the content of the prediction was false, rather than bring it about that the prediction had a truth-value.  Not even God can restore virginity*.

This suggests that the Law of Excluded Middle applies to future tense statements, but this causes him puzzlement, expressed in the following 'aporetic triad'.

1. Law of Excluded applies unrestrictedly to all declarative sentences, whatever their tense.
2. Presentism: Only what exists at present exists.
3. Truth-Maker Principle: Every contingent truth has a truth-maker.

They can't all be true, according to him, because the conjunction of any two implies the negation of the third. So here is a genuine insoluble problem. Each has a strong claim to our acceptance, but all of them cannot be true together.

Is that right? First, I don't see why the three statements are logically inconsistent.  Why can't the truthmaker for a future tense statement exist now, in the present? However, presumably Maverick buys the argument I gave here.  If the truthmaker exists now, and given that we cannot change the immediate present or the past, we cannot change the truthmaker’s existence. So we cannot change the future, for the truthmaker that exists now makes the future true, but we can change the future, ergo etc.  So we can assume the additional premise

4. The truthmaker for any contingently true proposition exists only at the time for which the proposition is true.

By the expression 'time for which' a proposition is true, I am attempting to translating the medieval Latin pro tempore, meaning, roughly, any time at which any present tense statement corresponding to a non present tense statement is true. For example, if I truly say 'it will rain next week', when today is 3 December 2011, the time for which my statement is true = any day next week, i.e. the week commencing Monday 5 December.  The corresponding present tense statements are 'it is raining today', uttered on Monday, or on Tuesday, Wednesday etc.

But statements 1-4 above cannot all be true.  If only things in the present exist, future truthmakers do not exist. It may be that they will exist, but they don't now.  So the statement 'it will rain next week' has no truthmaker (although, if it does rain, it may be that it will have one).  And yet law of excluded middle surely applies to any statement whatever.  If it does rain next week, and I say that it will rain next week, then surely we can say next week that 'Edward was right'.

Which of the four statements above is incorrect?  (Rhetorical question, for those who read my blog regularly).

*Pace Peter Damian.

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53 Comments:

Blogger Anthony said...

I see absolutely no reason to believe 1.

5:18 pm  
Blogger Anthony said...

I suppose 1 might be true if, by declarative sentence, you mean a sentence to which LEM applies.

But I don't think "declarative sentence" is the term you're looking for.

"It is 12:30 PM right here right now" is a declarative sentence.

5:30 pm  
Blogger Edward Ockham said...

What part of the term 'unrestrictedly' do you not understand?

5:35 pm  
Blogger Anthony said...

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5:44 pm  
Blogger Anthony said...

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5:48 pm  
Blogger Anthony said...

>> What part of the term 'unrestrictedly' do you not understand?

I don't know. I was taking it to mean "without exception". What does it mean?

5:49 pm  
Blogger Edward Ockham said...

>>I don't know. I was taking it to mean "without exception". What does it mean?

"without exception" will do.

5:57 pm  
Blogger Edward Ockham said...

Thus "1. Law of Excluded applies without exception to all declarative sentences, whatever their tense.

If it's a declarative sentence, then LEM applies, no exception.

5:57 pm  
Blogger Anthony said...

It's still ambiguous what is meant by the "declarative" restriction in "all declarative sentences".

If one says that a declarative sentence is a sentence which declares something, well then one could still argue that a contingent future tensed sentence declares nothing (or declares something other than a future tensed proposition), essentially begging the question.

For example, I have argued before that a statement such as "I will go to the store tomorrow" (or "I will pay you back"), if it declares anything, is declaring a current intent, and not a state of the future.

5:59 pm  
Blogger J said...

1. The LOEM is a tautology.


2 & 3 are metaphysical posits (#2 positivist dogma, or close to it).

The weather is not the periodic table for that matter. Few people, even Humeans would bet against the boiling point of H20 at sea level being 100C in 10 years. (CS Peirce often reminded philosophasters of.... Continuity)

6:23 pm  
Blogger Edward Ockham said...

>>If one says that a declarative sentence is a sentence which declares something,

yes

>>well then one could still argue that a contingent future tensed sentence declares nothing

In which it is not a declarative sentence. (1) applies to all 'declarative sentences'.

6:38 pm  
Blogger Anthony said...

2 is either a tautology (only what exists at present presently-exists) or a denial of presentism (only what exists at present ever-exists) depending on what is meant by "exists".

6:47 pm  
Blogger Anthony said...

>> >>well then one could still argue that a contingent future tensed sentence declares nothing

>> In which it is not a declarative sentence.

And is not a proposition either.

So if that's your argument for 1, then contingent propositions don't exist, and 3 and 4 hold vacuously.

7:07 pm  
Blogger Edward Ockham said...

>>So if that's your argument for 1, then contingent propositions don't exist, and 3 and 4 hold vacuously.

I don't follow your reasoning at all. Why does the argument for (1) imply that contingent propositions don't exist?

>>2 is either a tautology (only what exists at present presently-exists) or a denial of presentism (only what exists at present ever-exists) depending on what is meant by "exists".
<<

What's wrong with this? An anti-presentist would claim that some things exist (where 'exist' is used in a supposed 'tenseless' way) that are not present.

7:22 pm  
Blogger J said...

Well, it could be put in the LOTEM form---either presentism holds, or it doesn't. But to say it does would require a bit of a metaphysical story, would it not.

Informally speaking, departments of History would seem be a counterargument. Or fossils. At least looking backwards history exists. Banal perhaps. Them my contention is most philosophy chestnuts become banalities.

However logicians can't really speak of futurity, or probability---that's for statisticians. Logicians deal with facts, tautologies and argument forms, or nada. even BV's "contingent truths" seems' odd. Truths are non-contingent by definition. He means..analytical and synthetic propositions, more or less.

7:30 pm  
Blogger Anthony said...

>> Why does the argument for (1) imply that contingent propositions don't exist?

Well, I'm taking for granted that it's only possible to change the future.

The argument for (1) is that a contingent future tensed sentence declares nothing. So by that argument there are no contingent propositions about the future, either.

7:35 pm  
Blogger Edward Ockham said...

>>The argument for (1) is that a contingent future tensed sentence declares nothing. So by that argument there are no contingent propositions about the future, either.

How is the claim that 'a contingent future tensed sentence declares nothing' an argument for (1)? Perhaps you mean that this claim is consistent with (1)?

7:39 pm  
Blogger J said...

Why not ask "Ant." to define the LOTEM for starters, Ock. Or provide the truth table (not ad hominem--just that he ...has no idea what this is about).

7:42 pm  
Blogger Anthony said...

>> How is the claim that 'a contingent future tensed sentence declares nothing' an argument for (1)?

It's part of an argument for (1).

1a. LEM applies unrestrictedly to non-future-tense declarative sentences. (the rest of the argument)
1b. LEM applies to non-contingent declarative sentences. (the rest of the argument)
2. A declarative sentence declares something. (definition)
3. A contingent future tensed sentence declares nothing.
4. A contingent future tensed sentence is not a declarative sentence. (2&3)
5. LEM applies unrestrictedly to all declarative sentences, whatever their tense. (1&4)

7:50 pm  
Blogger Edward Ockham said...

OK, I thought that's what you meant (just checking). But the assumption

>>A contingent future tensed sentence declares nothing.

is false. If I say that it will rain next week, I have said something, namely that it will rain next week. 'Declaring' is just a fancy term for 'saying that..'.

7:59 pm  
Blogger Anthony said...

>> >> 2 is either a tautology (only what exists at present presently-exists) or a denial of presentism (only what exists at present ever-exists) depending on what is meant by "exists".

>> What's wrong with this?

I don't believe anything is wrong with it.

>> An anti-presentist would claim that some things exist (where 'exist' is used in a supposed 'tenseless' way) that are not present.

So a claim that everything which exists-presently, exists-eternally, would be presentist? That can't be right.

8:09 pm  
Blogger Anthony said...

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8:12 pm  
Blogger Anthony said...

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8:14 pm  
Blogger Anthony said...

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8:18 pm  
Blogger Anthony said...

>> 'Declaring' is just a fancy term for 'saying that..'.

Hmm...I'm not sure of that. You can't substitute "saying that" for "declaring", can you?

>> If I say that it will rain next week, I have said something, namely that it will rain next week.

What is that it will rain next week? You say it is something. What is it?

Aren't you committing the fallacy of reification?

8:20 pm  
Blogger Anthony said...

What is that it will rain next week? You say it is something. What is it?

What is its identity? What kind of rain is it? Is it a downpour, or just a sprinkle? Is the rain coming during the day, or at night?

8:34 pm  
Blogger J said...

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8:51 pm  
Blogger J said...

It's something like a Laplacean issue, rather than logical Ock. Accurate predictions of the weather are made now, via punching all the relevant variables and atmospheric conditions into databases, etc. Weathergal (following orders from NCAR or something) says "showers over the weekend". She's making a future tense statement, and lo it turns out right (say she has a "weather prediction average" and shes right..75% of the time). And eventually a ...perfected science of meteorology-- could come about-- in a century or two. Thus the truth of next week's weather or even a year from now could be known (so, the "truthmakers"--ie relevant conditions are known). But Bubba at the hardware store doesn't know it, at least now. What do philosophasters call that? Agency. An atmospheric physicist..has the requisite level of agency and might know, or have a close approximation of what the weather will be. Bubba doesn't.

Similarly for economics, market activity--ie, this stock will go up. As ...a pro. economist knows. Bub. doesn't. In other words the merely grammatical issue, or the LOTEM is not really the issue (LOTEM always applies but it's trivial). Probability is the issue, and knowledge thereof.

8:53 pm  
Blogger Anthony said...

"And eventually a ...perfected science of meteorology-- could come about-- in a century or two. Thus the truth of next week's weather or even a year from now could be known."

Nope. Not possible. Human choices affect the weather, certainly within the timespan of a year.

9:00 pm  
Blogger Anthony said...

"Similarly for economics, market activity--ie, this stock will go up. As ...a pro. economist knows."

So, you are denying human free will?

I could see how you might not realize that the weather one year from now is contingent on human free will (though if you examine weather patterns in the days following September 11, 2001 you will likely realize that they are).

But surely you realize that human choices affect stock prices.

9:06 pm  
Blogger J said...

Maybe google Laplacean determinism for a few months Ant. And neither rain dances nor Fed admins will be doing jack about the next Katrina will they.

The human cognitive apparatus poses a different issue...but if you think it's some Cartesian ghost with complete "free will"..stop eating or drinking agua and see how the ghost does

9:59 pm  
Blogger Anthony said...

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10:10 pm  
Blogger Anthony said...

>> And neither rain dances nor Fed admins will be doing jack about the next Katrina will they.

Just because we can't predict exactly *how* we affect something, that doesn't mean we don't affect it.

You are the one who suggested that would be able to predict, in a mere couple centuries, exactly *how* the weather is affected by the inputs (of which we are a part). I reject that.

>> but if you think it's some Cartesian ghost with complete "free will"..stop eating or drinking agua and see how the ghost does

Nope, I don't think we are ghosts. Try another strawman.

10:13 pm  
Blogger Anthony said...

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10:17 pm  
Blogger Anthony said...

It's as though you're saying that, within 200 years, gamblers will be able to determine the outcome of the spin of the roulette wheel.

But if that were the case, surely the casino would also figure out that algorithm, and would use it to spin the wheel with a different amount of force.

The ridiculous assumption is that we're going to figure out, in a mere 200 years, the exact algorithm to determine the outcome of the roulette wheel. There's no doubt whatsoever that human choice (how hard the wheel is spun) is a significant factor in the outcome of the spin.

10:18 pm  
Blogger J said...

No, you said you believed in free will. Now, had you bothered to read Descartes or any work of philosophy--even ebonics Ayn Rand-- you'd realize that ...positing free will does imply something like..a ghost (and a story justifying it, or not).

Re meteorology: certainly weather forecasts are superior now to what they were 100 years ago. More science, and servers to crunch data. So, in another century ...who knows. Could be far more accurate. Laplace-land doesn't go into effect manana. But in 200 years...the answer to .."are there Truthmakers in regard to weather forecasting?" might be affirmative.

10:32 pm  
Blogger J said...

The point was on the weather, wasn't it. And economics. The ridiculous assumption is that you think you know something about philosophy, probability, or roulette for that matter (and yes, were some wizard gambler --with say a nano- calculator--to know all the initial conditions of a r. wheel--force of spin, weight, etc-- he might predict a roll. Same for dice)

10:41 pm  
Blogger Anthony said...

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10:51 pm  
Blogger Anthony said...

>> you'd realize that ...positing free will does imply something like..a ghost (and a story justifying it, or not)

I do realize that. You seem to be the one who doesn't.

>> Re meteorology: certainly weather forecasts are superior now to what they were 100 years ago. More science, and servers to crunch data. So, in another century ...who knows. Could be far more accurate.

It will be far more accurate. But you won't be able to know whether or not it will rain in a particular place one year in the future. Weather is too dependent on initial conditions (of which human choices are a part).

>> The point was on the weather, wasn't it. And economics.

Indeed. Are you denying that the price of a stock is contingent on human choices? If you predict that a stock will rise 50%, does that make it impossible for all the employees of that company to revolt and send the stock price falling?

If you predict that a tornado will hit Kansas in 11 months and 23 days, does that make it impossible for a gardener in Tokeo to kill a butterfly, and thereby stop it from flapping its wings?

>> and yes, were some wizard gambler --with say a nano- calculator--to know all the initial conditions of a r. wheel--force of spin, weight, etc-- he might predict a roll. Same for dice

But how can he know all the initial conditions without knowing how hard it's going to be spun/rolled?

10:52 pm  
Blogger J said...

NO, you don't understand. You're positing complete free will. Im not.

Maybe like start with the wiki on...free will/determinism. And the one on probability as well.

10:55 pm  
Blogger Edward Ockham said...

>>What is that it will rain next week? You say it is something. What is it?

No, the statement or claim that it will rain next week is not itself something that can rain.

11:36 pm  
Blogger Anthony said...

>> >>What is that it will rain next week? You say it is something. What is it?

>> No, the statement or claim that it will rain next week is not itself something that can rain.

How does that answer the question?

You say the statement "It will rain next week." declares something. Specifically you say that it declares that it will rain next week. Right?

So you are saying that that it will rain next week is something. I'm asking you what it is. What is that it will rain next week? Seems to me like an abstraction without a concrete - in other words, not something at all.

11:58 pm  
Blogger Anthony said...

There's a wiki on free will/determinism?

12:05 am  
Blogger Edward Ockham said...

>>So you are saying that that it will rain next week is something.

The extra 'that' makes the parsing clear. Yes of course. 'Bill said something'. 'Nearly anything A says makes sense'. 'Some things B says do not make sense'. 'Nothing C says makes sense'. 'D said something about rain yesterday'. And so on. Looks like quantification to me. I will post on this tomorrow.

9:52 am  
Blogger Anthony said...

So you say that that it will rain next week is something. So that it will rain next week exists? And to exist, from (2), is to exist presently. Where does that it will rain next week presently exist?

1:02 pm  
Blogger Edward Ockham said...

>>So you say that that it will rain next week is something.

Certainly. If I say that it will rain next week, I have said something. Or perhaps you think I haven't said anything?

>So that it will rain next week exists?

Most certainly. What I have said is something, and everything exists, ergo etc.

>>And to exist, from (2), is to exist presently. Where does that it will rain next week presently exist?

Does everything have to exist somewhere?

These are good questions?

3:03 pm  
Blogger Edward Ockham said...

>>These are good questions?

I'm sorry, there should be no question mark. Your questions are, actually, quite good.

10:18 am  
Blogger Anthony said...

>> If I say that it will rain next week, I have said something. Or perhaps you think I haven't said anything?

If you say "It will rain next week", you've said "It will rain next week."

>> >> So that it will rain next week exists?
>> What I have said is something, and everything exists, ergo etc.

First off, you're begging the question.

Secondly, you believe that everything exists? Interesting.

Does Socrates exist? Is Socrates not something?

>> Does everything have to exist somewhere?

Everything that exists exists somewhere. As for whether or not everything exists, well that depends on what you mean by "exists". My understanding is that by "exists" you mean "exists-presently", in which case, no. Socrates is something, but Socrates does not exist-presently.

1:13 am  
Blogger Edward Ockham said...

My fault. I should have said "everything that is something, exists". You are right. Some things used to exist, which no longer exist.

9:11 am  
Blogger J said...

you've drifted away from the philosophical issue---(not the grammatical one) are there "truth makers" for propositions regarding future events?? (say weather forecasts...but dice tosses for that matter ). And the answer is...yes, with in qualifications. (they may be unknowable, given present state of science...ie, the weather in LA in 10 years). Meteorologists know what the weather will likely be for a few weeks, within a certain range (ie, likely to be some showers. But not likely a tornado or blizzard). They know something about the science of the weather--the truth conditions. And the knowledge of the weather (even with probabilistic elements) does have a nomological relation to any propositions thereof, or something of the sort. David Armstrong discussed this somewhere.

1:03 pm  
Blogger Anthony said...

>> I should have said "everything that is something, exists". You are right. Some things used to exist, which no longer exist.

Some things are not something?

11:49 pm  
Blogger Edward Ockham said...

>>Some things are not something?

Some things are not anything. And of course, some man (Socrates) is not a man. (Although he was a man).

9:36 am  
Blogger J said...

Maybe review like Russell on motion/change, Ock. And he brings in all the klassics ..Zeno, Plato, Aristotle, up to Leibniz /Newton etc.

Or at least check the wiki

4:56 pm  

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