Can we have knowledge of the future?

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If you accept only deductive reasoning as being justified, then we cannot have knowledge of the future.

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Tomorrow, nothing will exist which is both red all over, and green all over.

This is a conclusion I arrived at through deductive means.
I know it to be true. Its about the future.

So to answer the OP's question, ya we can have knowledge about the future.

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I don't believe that knowledge of the future qualifies under the guidelines of justified true belief.

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You can have reasonable expectation based on previous experience/precedent, and on recognition of causal sequence. We rely on anticipating the future every day - we park our car and assume it won't transmogrify into an elephant while we're gone. We use a combination of past experience and logical inference to predict that the sun will rise, that we will die etc.

This mightn't be knowledge strictly speaking, but it's predictive value is so high it functions pretty much as well as knowledge would. All these predictions exist on a continuum, the further down you go the less useful the prediction - 'I'm going to live until the end of this week' ranking higher than 'my cat will learn to play the violin'.

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You're talking of induction. The sun rose yesterday and the day before that so I believe it will rise tomorrow. Many would argue that induction is not knowledge at all. There is no reasoning behind induction. Of course, simplicity is inductions best ally.

[Bork]

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I don't believe that knowledge of the future qualifies under the guidelines of justified true belief.

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I just gave you an example.
Tomorrow, nothing will exist which is both red all over, and green all over.


I do believe it. Do you think it isn't true or that my belief isn't justified. Please explain.

Here is another one: A week from today there will be no squirrel which is fatter than itself.

[chezlaw]

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I don't believe that knowledge of the future qualifies under the guidelines of justified true belief.

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I just gave you an example.
Tomorrow, nothing will exist which is both red all over, and green all over.


I do believe it. Do you think it isn't true or that my belief isn't justified. Please explain.

Here is another one: A week from today there will be no squirrel which is fatter than itself.

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I think we usually accept that knowledge of tautologies is always possible. Not sure how relevent they are to the problem of knowledge and its a moot point as to whether they are about anything.

chez

[Bork]

Neither of my examples are logical tautologies.

They are necessarily true, but not by virtue of their logical form.

The problem that was posed was whether we can know anything about the future. The answer is yes because we can deduce necessary truths. Some of which are tautologies( my examples are not). Even if they were they still count as knowledge about the future, useful or not.

Now if he was asking whether we can know which possible future events will occur then the answer is also yes. Unless you are some kind of uber old fashion skeptic who thinks no inductive support can justify a belief. This person would also be commited to say we arent justified in believing that we have hands, or that we know our parent's names, or that physical objects exist, etc.

[peritonlogon]

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Neither of my examples are logical tautologies.

They are necessarily true, but not by virtue of their logical form.


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Actually what you said is true precisely because of it's logical form... Even if you did not write it down, or elucidate it.

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Tomorrow, nothing will exist which is both red all over, and green all over.

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If we can all except this proposition.

All logical forms that are true today are true any other day.

"Tomorrow, nothing will exist which is both red all over, and green all over"

Is true because of this identity


All-red-all over things are red-all-over things

and its converse

All non red-all over-things are non red all over things.

and this proposition.

A green all over thing is a non red-all-over thing.

Since, principle of non contradiction "A thing can not both be and not be in the same respect at the same time"

Which means, what you said is just a specific instance of the principle of non-contradiction, which is a rule of logic that is also provable by tautology.

[Bork]

Nothing that is red all over is green all over.

Its logical form is: Something that has property X cannot have property Y.

You can make substitutions which make this true and which make it false.
It is NOT true because of its form. It is not a logical tautology.

You seem to be confused about what logical form is so I will provide you with a couple links.
http://plato.stanford.edu/entries/logical-form/
http://plato.stanford.edu/entries/analytic-synthetic/

The above is completely tangential to the OP's question. The fact remains if you only accept deductive justification for knowledge then you better be an almost absolute epistemological skeptic. Almost every belief we form is the result of induction.

[Bork]

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All logical forms that are true today are true any other day.

"Tomorrow, nothing will exist which is both red all over, and green all over"

Is true because of this identity


All-red-all over things are red-all-over things

and its converse

All non red-all over-things are non red all over things.

and this proposition.

A green all over thing is a non red-all-over thing.

Since, principle of non contradiction "A thing can not both be and not be in the same respect at the same time"

Which means, what you said is just a specific instance of the principle of non-contradiction, which is a rule of logic that is also provable by tautology.

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One more point.
Just because you used a tautology (you used more than one btw) in your 'proof' of my statement it does not follow that my statement itself is a a tautology or an instance of the the tautology that you invoked in the proof.

[chezlaw]

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Neither of my examples are logical tautologies.

They are necessarily true, but not by virtue of their logical form.

The problem that was posed was whether we can know anything about the future. The answer is yes because we can deduce necessary truths. Some of which are tautologies( my examples are not). Even if they were they still count as knowledge about the future, useful or not.



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They are necessarily true by virtue of the meaning of the parts. Thats what I mean by tautology, but lets not have an extremely dull conversation about that [img]/images/graemlins/smile.gif[/img]

The point remain, all you are saying is that you know that necessarily true propositions wont be false tomorrow.

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Now if he was asking whether we can know which possible future events will occur then the answer is also yes. Unless you are some kind of uber old fashion skeptic who thinks no inductive support can justify a belief. This person would also be commited to say we arent justified in believing that we have hands, or that we know our parent's names, or that physical objects exist, etc.

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I dont think thats what skeptics claim. Induction can support beliefs, one question is can it support knowledge. Even if you allow that induction can support knowledge then thats not enough to make knowledge possible.

chez

[maurile]

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If you accept only deductive reasoning as being justified, then we cannot have knowledge of the future.

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Tomorrow, nothing will exist which is both red all over, and green all over.

This is a conclusion I arrived at through deductive means.
I know it to be true. Its about the future.

So to answer the OP's question, ya we can have knowledge about the future.

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Your statement isn't about the future. It's about word definitions.