tommyc

Well, I certainly don't believe it's unfair that religious believers should have to prove their arguments in the same way everyone else has to.

I always thought that to prove something, you have to show that you've proved it. You can't just say "I've proved it", without some backup, or everyone could go around saying "I've proved that unicorns exist, trust me on that" or whatever. The point is that "proving" there is a God without showing that you have proved it is a pretty pointless exercise.

tommyc

of course, if you just wish to proclaim that you have proved god exists and not give an explanation, then fair enough, but don't expect anyone to believe you.

Just out of interest, is your first argument (G), the reason you believe in God? if so, then please be careful, as wandering salesman may be able to take advantage of you.

Salesmane: Good afternoon!
Anon: Hi!
Salesman: If I tell you this is a great product, you will buy it.
Anon: OK
Salesman: Here, check out these invisible condoms, they're great!
Anon: OK, I'll take a box of 200 please.

Ender

Typical theist- ignoring my posts and addressing only what seems germane to his case. After consulting my library I misspoke- a sound argument is a deductive argument that is valid and has all true premises. Get it? It is not sound first, then valid- but whether it is valid. Your argument is valid because of its form in symbolic logic. But your reasoning on why it is sound is circular.

False. This is a circular answer. The argument is valid because the conclusion does follow the premises in all possible worlds- but the soundness, that is whether all the premises are true, is questionable. In a valid deductive argument, it is impossible for the premises to be true and the conclusion false.

No you walked into it- the argument is valid because of its form- if P then Q, and P, therefore, Q.

That was my intention- to ask you why do you think the first premise is true? Your answer is "because it is valid and the premises are true."

If P then Q, and given P, therefore Q is valid. But the truth validity of the premises are open to question.

Correct. You have given me a circular answer. You lose.

Your understanding of validity in logic is incorrect. The argument form is valid, in all possible cases.

No need to, since I left it totally up to you. Sort of like giving you a paintbrush and a pail of paint and consequently you end up painting yourself in a corner.

~WiGGiN~

TollHouse

What the fuck? Really, what the living fuck? Are all premises true be default now? Did I just wake up in the Twilight Zone?

Bill Snedden

Quite right. It is the difference between making a statement purported to be true and demonstrating that your statement is actually true.

"The moon is made of green cheese" is a statement. However, is it true?

P1. If something exists, then the moon is made of green cheese.
P2. Something exists.
C1. The moon is made of green cheese.

Here is a proof that the moon is made of green cheese. But is it true?

If not, why not? My argument is valid, for it follows the modus ponens structure. By your own logic, it is sound as well, as all of the premises are true. Or, are they?

If you are unwilling or unable to "show that you have proven 'G'", then why should we care?

As I can deny your first premise without contradiction, I have sufficient reason to doubt that your argument is sound. If you wish to convince anyone of its soundness you will need to supply further evidence OR break down that premise into further premises that cannot be denied without contradiction.

And further, if you do indeed teach logic and epistemology, then, IMO, your behavior in this thread can only be described as "deliberate obfuscation". Such behavior is normally associated with trolling, and not with a serious attempt at discussion or debate. If you have the intellectual capacity to teach philosophy, then you should have the intellectual capacity to understand exactly the points other posters are attempting to make. If you are in fact interested in serious discussion, I would suggest that you cease pretending that you don't understand that most people use the term "proof" in an informal sense meaning "prove" and address the real point most of the posters here have been making. Namely, that while your argument may be a proof, it doesn't really prove anything.

Regards,

Bill Snedden

[ May 02, 2002: Message edited by: Bill Snedden ]</p>

Adrian Selby

"I would be foolish to offer a demonstration of premise 1 until it is decided what will count as a demonstration. "

Sorry anon, I should have picked up on this in my previous post.

Can I ask then whether the best way to demonstrate whether something exists assumes God exists, is to look at something that exists, then explain why its evidence for the christian God to exist.

let's start with your computer, that you use to type with. I have one similar. These are somethings. Can you show me why, looking at these somethings, you feel able to assert that God must exist, simply because we're sat in front of these somethings? Only I'm looking at my something, and I do not have the first idea how its existence is presupposed by an all powerful all knowing all benevolent being.

Is this a fair request for a demonstration. I'm not asking you to show me God as such, just that I look at a whole world of somethings in my environment, and do not see how any of it can only exist because the christian God exists. Perhaps you'd explain how you arrived at this premise with reference to our computers in particular.

Adrian

Clutch

I retract this. You have since responded. Thank you. What is *not* seriously denied in the professional literature is that to assert is to present as warranted, and not simply to present as true. (That's what Moore's Paradox shows; "It's raining but I don't believe it" can be true, but even if true is unassertible by me, precisely because I cannot be in a position to have evidence for it.) Since you are asserting the soundness of your argument, you are presenting it as warranted. But you concede that there is no evidence on display for this claim.

The only reasonable conclusion for me to draw is not that there is a proof, but that I do not find it convincing -- as if this were a plausibility judgement of something I could antecedently recognize as a proof. The result is, rather, that I have no reason to conclude that there is a proof. You may, of course, continue to *say* that it is a proof, and that your warrant for so asserting is kept in your back pocket and is not to be shared. But your lately emerging claim, that the reason for this whole epicycle is to point out an *unfairness* in the treatment of apologists, does not fly. If by your own admission I have been given no reason to regard your argument as a proof, it is hardly "unfair" of me not to regard it as a proof -- nor to reject as *unfounded* the claim that it is a proof.

This leaves us with you being free to continue saying that this is a proof, and me being rationally warranted in regarding each such claim as groundless. If that's the logical space within which you consider this to be a proof of anything, help yourself. But by not being upfront about this from the outset, you *have* been a time-waster. So I assert; and the evidence fills four webpages.

Clutch

Bill Sneddon: Nice analogy. You can also do it without locating the dubiousness in the conditional premise:

(1) If there is a thumb-sized piece of manganese on the nearest planet humans will never examine, then there is some manganese on the nearest planet humans will never examine.

(2) There is a thumb-sized piece of manganese on the nearest planet humans will never examine.

Therefore,
(3) There is some manganese on the nearest planet humans will never examine.

Ah, magic! A *proof* of an empirical proposition about something we will never examine! And better yet, nobody can ever show otherwise, since I assume everyone accepts (1) as true, and by definition (2) cannot be demonstrated false.

JB01

The ancient Greek philosophers, who introduced the concept of formal proof (Euclid) and enumerated the forms of several simple syllogisms (Aristotle), regarded axioms as self-evident truths. By contrast, in modern mathematics, axioms are regarded as arbitrary assumptions, which may be used to set up formal systems that are of interest simply because of their logical structures.

It is unnecessary (because it is impossible) to demonstrate the truth of the axioms one is using in a proof. However, they will only be admissible within the formal systems they define, and readers will only have to concede the soundness of any valid argument based on them within such a formal system. You can't formally prove anything to anyone without first surmising that they agree to all your starting premises.

Meanwhile, in the real world, we have no "formal system" from which to deduce truth, and deductive arguments for the existence of material entities have no value at all. The only convinving argument for the actual existence of a deity must rely on induction, i.e., evidence.

Goliath

anonymousj,

You're teaching a logic class? How dreadful. You have demonstrated your extreme level of ignorance of logic.

Again, you have asserted that "If something exists, then God exists." This is not an axiom (since you are TEACHING a logic class, I will assume that you know what an axiom is). Therefore you must prove said assertion.

This is all that you've really proven:

Again, you have NOT proven your assertion that "If something exists, then God exists." Thus you CANNOT reduce your theorem above to:

I really don't know how to be more clear about this.

Sincerely,

Goliath