/lit/ - Literature

[Anonymous No.14814245]

This apparently how philosophers prove fatalism, ie that whatever will happen in the future is already unavoidable:

(1) There exist now propositions about everything that might happen in the future.[1]
(2) Every proposition is either true or else false.
(3) If (1) and (2), then there exists now a set of true propositions that, taken together, correctly predict everything that will happen in the future.
(4) If there exists now a set of true propositions that, taken together, correctly predict everything that will happen in the future, then whatever will happen in the future is already unavoidable.
∴ (5) Whatever will happen in the future is already unavoidable.

Are these people for real? I mean, how can you not see a glaring hole in this argument?

[Anonymous No.14814494]

>>14814245
Show me your hole.

[Anonymous No.14814562]

>>14814494
>tomorrow it will either rain or it won't
>one of these has to be correct
>therefore tomorrow's weather is unavoidable
The whole argument says absolutely nothing.

>(4) If there exists now a set of true propositions that, taken together, correctly predict everything that will happen in the future, then whatever will happen in the future is already unavoidable.
This is a tautology. It translates to "if we can predict the future, then the future will be unavoidable".
>∴ (5) Whatever will happen in the future is already unavoidable.
This is a non-sequitur.

[Anonymous No.14814804]

>>14814562
I'm not a fatalist, but the argument's not so dumb.
>tomorrow it will either rain or it won't
>one of these has to be correct
>therefore tomorrow's weather is unavoidable
I think (1) and (2) are saying that if e.g. the proposition
>It will rain tomorrow
is true today (whether we know it or not), then it's going to rain tomorrow. In which case, the future's already settled.
>This is a non-sequitur.
No, the logic of the argument's good, it's a mixture of hypothetical syllogism and modus ponens. I think at least one of the premises has to be false.

[Anonymous No.14815088]

>>14814804
>if the proposition "it will rain tomorrow" is true today (whether we know it or not)...
A proposition about the future doesn't have a truth value. In fact, most logicians wouldn't even call it a proposition.
https://en.wikipedia.org/wiki/Problem_of_future_contingents
An actual proposition is a statement about the world, and it is true if and only if it corresponds to a fact.

Moden ponens cannot be employed like that for statements about the future. Even Aristotle acknowledged that.

[Anonymous No.14815142]

>>14815088
>A proposition about the future doesn't have a truth value
>It's neither true nor false that the sun will rise tomorrow
>It's neither true nor false that I will die
>There are no true predictions
>I predict there will never be any true predictions
>I support my 'argument' with Wikipedia even though the Wikipedia page in question doesn't give any support at all for my outrageous claims

>An actual proposition is a statement about the world, and it is true if and only if it corresponds to a fact
>My definition of 'proposition' implies there are no false propositions, since they all have to correspond with facts
>I am silly
>Moden ponens cannot be employed like that for statements about the future. Even Aristotle acknowledged that.
What book did he acknowledge this in?

[Anonymous No.14815184]

>>14814245
Richard Taylor himself wasn't a fatalist

[Anonymous No.14815190]

The fallacy here is not exactly evident. It rests on the premise that all propositions have truth values. If this is the case, then propositions about the future have content and the future must be fixed. Aristotle's counter is that statements about the future are only true when they become true, but then we have to accept that not all propositions have truth values.

[Anonymous No.14815199]

>>14814245
this is retarded and they should feel bad about themselves.
gas the analytic school.
also the continental, for good measure.

[Anonymous No.14815480]

>>14815142
>>It's neither true nor false that the sun will rise tomorrow
you're making some pretty basic logic errors.
let A = tomorrow it will rain
we can conclude that, by the law of the excluded middle, ether A or ¬A must be true
let P = tomorrow it will either rain or it won't rain
P = A U ¬A
the statement you made was P, not A. P has a true value, because it is logically deduced from A, but you don't know the truth value of A. A at this time is neither true nor false.

[Anonymous No.14815497]

>>14814245
Define "unavoidable".
If unavoidable means "will have a given outcome no matter what", then of course the argument you presented is flawless.
You're just buttmad because you want "unavoidable" to mean "we can predict what it is", which is completely different.

The universe could be entirely deterministic, and we might still not know enough about the rules to actually predict everything.

[Anonymous No.14815541]

>>14815480
>It's neither true nor false that the sun will rise tomorrow
is logically equivalent to
>tomorrow it will either rain or it won't rain
? You wot lad?
>You don't know the value of A, therefore A at this time is neither true nor false
>I don't know it yet, therefore not only is it not true, it's not false either
Nah.

[Anonymous No.14815598]

>>14815480
How's about a constructive dilemma?
>P=it will rain tomorrow
>Q=there is at least one true future contingent proposition

>(1) P or not-P
>(2) If P then Q
>(3) If not-P then Q
>Therefore (4) Q