Tricks New Atheists and Theists Play (Part 1)

[Tree of Life]

The first one. You cant prove that earth is the only source for teapots in the universe (that, again, would be proving a negative).

Also the second. You cant prove that there never was a secret nasa mission to shoot a tea pot towards jupiter.

The proof consists in the logical validity of the conclusion. If we assume that (1) and (2) are true, then (3) is necessary and a negative statement is thereby proven.

 

[Tree of Life]

Wrong again.

Is it possible that you're wrong?

 

[Tree of Life]

Never heard of substitute teachers?

I don't think you understand the idea of modus tollens. Have you ever taken a logic course? I'm demonstrating that a negative statement can be proven by deriving it from two facts that we already know or accept. Of course if those propositions are not true, then the conclusion is unsound. But that's not the point of the exercise. The point is to show that it is logically possible to prove a negative statement.

 

[durangodawood]

Do you not believe that modus tollens proves a negative?

Its not enough for the form to work if it relies on unprovable premises. It just shoves the dispute up or down a level.

The unicorn example illustrates this perfectly. But the author thinks its "not reasonable" that I take issue at another level because, if I do, then we can argue premises all the way down endlessly to absurdity!

Sorry, thats not going to erase from my mind the fact that we discover new fossil species regularly,

 

[Nithavela]

The proof consists in the logical validity of the conclusion. If we assume that (1) and (2) are true, then (3) is necessary and a negative statement is thereby proven.

You dont really know what a proof is, do you?

 

[Tree of Life]

Its not enough for the form to work if it relies on unprovable premises. It just shoves the dispute up or down a level.

The unicorn example illustrates this perfectly. But the author thinks its "not reasonable" that I take issue at another level because, if I do, then we can argue premises all the way down endlessly to absurdity!

Sorry, thats not going to erase from my mind the fact that we discover new fossil species regularly,

That's fine. That just goes to show that we may not be able to prove every negative statement. But the subject of the OP is whether or not any negative statement can be proven. If we know that premises (1) and (2) are true for a given modus tollens argument, then we also know that conclusion (3) - which is a negative statement - is true.

 

[Nithavela]

I don't think you understand the idea of modus tollens. Have you ever taken a logic course? I'm demonstrating that a negative statement can be proven by deriving it from two facts that we already know or accept. Of course if those propositions are not true, then the conclusion is unsound. But that's not the point of the exercise. The point is to show that it is logically possible to prove a negative statement.

You still have to produce a single valid example.

 

[Tree of Life]

You dont really know what a proof is, do you?

I do.

 

[Tree of Life]

You still have to produce a single valid example.

My college professor example is logically valid.

 

[Tree of Life]

You still have to produce a single valid example.

Maybe it would help if you could provide an "If A then B" proposition that you accept. Do you believe that there is a necessary relationship between any two things in the world?

 

[durangodawood]

That's fine. That just goes to show that we may not be able to prove every negative statement. But the subject of the OP is whether or not any negative statement can be proven. If we know that premises (1) and (2) are true for a given modus tollens argument, then we also know that conclusion (3) - which is a negative statement - is true.

In your example we dont know that statement 1 is true. its just stipulated. Maybe staffing decisions changed without our knowing.

I'm not sure that modus tollens can prove prove a negative without granting some unprovable premises.

Now I think modus is just a trick for shifting the location where proof has to happen.... and pretending that made the issue go away.

 

[Tree of Life]

Here's one that you all might find more persuasive:

1. If proofs exist for negative statements, then such proofs will be universally persuasive.
2. No proofs are universally persuasive.
3. Therefore no proofs exist for negative statements.

 

[Tree of Life]

In your example we dont know that statement 1 is true. its just stipulated. Maybe staffing decisions changed without our knowing.

I'm not sure that modus tollens can prove prove a negative without granting some unprovable premises.

Could you provide an example of an "If A then B" proposition that you accept? Do you believe that there is a necessary relationship between any two things in the world?

 

[Nithavela]

Maybe if would help if you could provide an "If A then B" proposition that you accept. Do you believe that there is a necessary relationship between any two things in the world?

Not my job to prove the unprovable for you.

 

[ToddNotTodd]

You said you had no opinion concerning them. I assume that means that you neither accept nor reject them. Did you mean something different?

No, that's what I mean. I was assuming that you meant that I couldn't be convinced of your premises.

Logical proofs are possible, necessary, and quite compelling. If A then B. A. Therefore B. That's a logical proof. So long as premises A and B obtain, conclusion C is necessary.

Formal logic is more akin to math. Aristotle doesn't seem to consider it part of Philosophy. He thought of it more as a tool that Philosophy uses.

And in your example we're not talking about formal logic.

No. But proof has to do with persuasion and acceptance. Proof matters because it actually has an affect on how people think and live.

You were talking about accepting premises. That's not proof.

 

[Tree of Life]

Not my job to prove the unprovable for you.

I take it that you do not believe that any two things in the world are necessarily related and that you would reject all "If A then B" propositions. I conclude that further discussion would be unfruitful because we have no common ground.

 

[Tree of Life]

No, that's what I mean. I was assuming that you meant that I couldn't be convinced of your premises.



Formal logic is more akin to math. Aristotle doesn't seem to consider it part of Philosophy. He thought of it more as a tool that Philosophy uses.

And in your example we're not talking about formal logic.



You were talking about accepting premises. That's not proof.

Maybe you could define what you think constitutes proof.

 

[durangodawood]

Here's one that you all might find more persuasive:

1. If proofs exist for negative statements, then such proofs will be universally persuasive.
2. No proofs are universally persuasive.
3. Therefore no proofs exist for negative statements.

Ha Ha.

But, your honor, "universally persuasive" goes to the state of mind every single being. I personally know one or two who think some very true things are false.

 

[Tree of Life]

1. If my naked skin touches the fire then it will get burned.
2. My skin did not get burned.
3. Therefore my naked skin did not touch the fire.

 

[Tree of Life]

Ha Ha.

But, your honor, "universally persuasive" goes to the state of mind every single being. I personally know one or two who think some very true things are false.

I think we could define "universally persuasive" in a way that excepted people with mental disabilities or mental illness.