Weak arguement

[555]

I wonder if this is correct:

* P1. If there's not sufficient evidence to believe in X, then it is reasonable to assume that X does not exist.
* P2. Therefore, i assume X does not exist.
* C1. X does not exist since P => P is true and P = "X does not exist" from (2) above.

[Guttersnipe]

(P1) is definately contestable.
(P2) Though you've labeled this a premise, you worded it like it was a conclusion drawn from (P1). But it doesn't follow from (P1) at all. Maybe with an implied premise such as (IP1.5) "There isn't sufficient evidence to believe in X." Then you could get something like (P2) via modus ponens.
(C1) The statements "I assume X does not exist" and "X does not exist" are in no way equivalent. I'm not sure what the symbolic conditional was referring too, maybe P1. Anyways, the most you can get out of this argument is "I assume X does not exist". Which doesn't look very interesting.

[555]

* P1. There is not sufficient evidence for me to believe that God exist.
* P2. Therefore it is reasonable for me to assume that God does not exist.
* P3. Therefore I assume God does not exist.
* C1. God does not exist since P => P is true and P = "God does not exist" from (3) above.

Ive been told is: For instance, one must assume an implicit conditional ("if there's not sufficient evidence to believe in X, then it is reasonable to assume that not-X") to get from P1 to P2, and a similar one to get from P2 to P3. It takes a big jump to get from P3 to C1. As a logical arguement, this isn't even valid, and requires a lot of interpretation in order to make it such.

[kennethamy]

I wonder if this is correct:

* P1. If there's not sufficient evidence to believe in X, then it is reasonable to assume that X does not exist.
* P2. Therefore, i assume X does not exist.
* C1. X does not exist since P => P is true and P = "X does not exist" from (2) above.

First: P1 is true only if it would be reasonable to expect there would be evidence of X if X existed. For instance, suppose there were a pearl at the bottom of the sea. There would be presumably no evidence which we could access for that. Yet that clearly does not mean that the pearl does not exist. That is why the maxim, absence of evidence is not necessarily evidence of absence, is true.

Second: P 2 would not follow from P1 whether or not P1 was true, since you would need the additional premise: there is not sufficient evidence to believe in X's (existence)

I don't understand what you wrote in C1.

Furthermore, "argument" is spelled that way. It does not have two "e's".

[trendkill]

A lot of people like to disagree with P1 because of what I consider to be questionable definitions of "evidence". I consider evidence to be anything that justifies belief; thus P1 is basically a tautology AFAIC. All beliefs that are insufficiently evidenced are unreasonable and vice versa.

As for the rest, I agree with Guttersnipe. The argument consists of a premise and a couple of non sequiturs.

[kennethamy]

A lot of people like to disagree with P1 because of what I consider to be questionable definitions of "evidence". I consider evidence to be anything that justifies belief; thus P1 is basically a tautology AFAIC. All beliefs that are insufficiently evidenced are unreasonable and vice versa.

.

But the OP wrote:

"If there's not sufficient evidence to believe in X, then it is reasonable to assume that X does not exist."

That does not say that "All beliefs that are insufficiently evidenced are unreasonable and vice versa."

So let me pose the same question to you. Consider the belief that there is a pearl at the bottom of the sea. Is it reasonable to assume that pearl does not exist? After all, if that pearl did exist, we would probably have no evidence that it exists. So why would the fact that we have no evidence that it does exist, make it reasonable that it does not exist? Wouldn't the reasonable thing be to withold belief as to whether or not there is a pearl at the bottom of the sea? After all, by your own principle, we have no evidence that it does not exist, and, therefore, it would be unreasonable to believe that it does not exist. Isn't that true?

[comiezapr]

* P1. There is not sufficient evidence for me to believe that God exist.
* P2. Therefore it is reasonable for me to assume that God does not exist.
* P3. Therefore I assume God does not exist.
* C1. God does not exist since P => P is true and P = "God does not exist" from (3) above.

Ive been told is: For instance, one must assume an implicit conditional ("if there's not sufficient evidence to believe in X, then it is reasonable to assume that not-X") to get from P1 to P2, and a similar one to get from P2 to P3. It takes a big jump to get from P3 to C1. As a logical arguement, this isn't even valid, and requires a lot of interpretation in order to make it such.

I assume, in my comments below, that C1 is a statement about the way the world is and is true OUTSIDE of the context of the deduction. If it were just within the context of the deduction then it would be uninteresting, anyway, so i think this is a reasonable way to intepret this deduction.

You are correct to say that this argument isnt valid. The jump from P3 to C1 is an enormous one that cannot be made. When you assume something you need to establish that the assumption is a correct one before assering the truth of that assumption in a context wider than the deduction. You cant just assume something and then say its so. Parallel it with this argument...

I assume that grass isnt red. Therfore, since this implies that grass isnt red, and nothing in the argument contradicts this, grass is red.

You cant do such things. This step is not one that can be done. All you can do is reiterate "grass isnt red" (which is essentially what you do anyway), but it is within the context of the deduction; you can say it only because you assumed it.

But also, the transition from P2 to P3 is undoable. From "It is reasonable to assume A" you cant then conclude A within the deduction; "it is reasonable to assume A" does not logically imply A. The deduction is a self contained thing. What you can do is, after having established that it is reasonable to assume A, start a new deduction and assume A. This would show, more overlty, the mistake from P3 to C1 and block any other atempts to stengthen the information deduced from epistemic claims. (The last comment relates to the present and previous parapgrahs.)

The whole project here is misguided. From "it is reasonable to believe that god doesnt exist" you cant conclude "god doesnt exist." It just cant be done. If there is some sort of aparatus that allows this transition the apparatus is incorrect. What is reasonable to believe doesnt need to be so. This is an invalid transition!

I think that harping on the transition from P1 to P2 isnt the place to focus on. However little the epistemic concepts of "reasonable belief", "evidence" and the relation between them are analyzed in this argument, i dont think this is a serious issue. At best this is a minor flaw that can be resolved by further clarification of the premises; this revision wouldnt harm the spirit of the deduction. The transition from P2 to P3 and P3 to C1 are not just flaws, they are outright wrong. There is no way to repair the deduction so that these transitions can be made; they are not truth preserving transitions.

Edit:I think i havent said anything new here, so sorry for spam if you find it this post to be as such.

[trendkill]

But the OP wrote:

"If there's not sufficient evidence to believe in X, then it is reasonable to assume that X does not exist."

That does not say that "All beliefs that are insufficiently evidenced are unreasonable and vice versa."I never said it did, and you haven't contradicted me yet. :P

So let me pose the same question to you. Consider the belief that there is a pearl at the bottom of the sea. Is it reasonable to assume that pearl does not exist?Depends.

After all, if that pearl did exist, we would probably have no evidence that it exists.Your question is muddled. Which pearl are we talking about here? Are you saying that we have no evidence that there are any pearls on the bottom of the ocean? Where on earth else do you expect to find pearls? :P Or are you saying that we have no evidence that there is a pearl at coordinates X on the ocean floor? I'll assume you meant the latter. In that case, I would say it is not reasonable to believe that there is one. Since pearls are known to be rare, the odds are against it.

So why would the fact that we have no evidence that it does exist, make it reasonable that it does not exist?It wouldn't, by itself. However, if we had absolutely no evidence either way, than I think both conclusions would be equally reasonable. Note that that is not the situation here.

Wouldn't the reasonable thing be to withold belief as to whether or not there is a pearl at the bottom of the sea? It might be reasonable not to form a strong opinion, but it would be unreasonable to fail to come to a conclusion at all when the evidence (probability) clearly favors one conclusion (i.e. no pearl at coordinates X).

After all, by your own principle, we have no evidence that it does not exist, and, therefore, it would be unreasonable to believe that it does not exist. Isn't that true?No.

[kennethamy]

No.

Trendkill wrote:

"All beliefs that are insufficiently evidenced are unreasonable and vice versa."

Kennethamy wrote:

"After all, by your own principle, we have no evidence that it does not exist, and, therefore, it would be unreasonable to believe that it does not exist. Isn't that true?"

Trendkill replies.

"No."

Kennethamy now replies:

:huh:

[trendkill]

I don't see what's to be confused about. Your statement makes false claims about my position, therefore it is not true. We do have evidence that the pearl does not exist, and it is reasonable to conclude that it doesn't exist.

Maybe you can tell me why you think your hypothetical is relevant rather than beating around the bush. Personally I see no real relevance to my position.

[kennethamy]

I don't see what's to be confused about. Your statement makes false claims about my position, therefore it is not true. We do have evidence that the pearl does not exist, and it is reasonable to conclude that it doesn't exist.

Maybe you can tell me why you think your hypothetical is relevant rather than beating around the bush. Personally I see no real relevance to my position.

What is the evidence that a pearl does not exist at the bottom of the ocean? There is no evidence that it does not exist, but that is obviously different from evidence that it does not exist. As I pointed out, absence of evidence is not evidence of absence unless we would expect there to be evidence of absence. What reason have you to think otherwise?

[trendkill]

What is the evidence that a pearl does not exist at the bottom of the ocean? There is no evidence that it does not exist, but that is obviously different from evidence that it does not exist.You're repeating yourself. I already responded to this in my first response to you in this thread. Dependent on what you mean by "a pearl does not exist at the bottom of the ocean", there is indeed evidence that it does not exist.

[kennethamy]

You're repeating yourself. I already responded to this, rather comprehensively in fact, in my first response to you in this thread.


Was your response credible? I forget. But isn't it clear that simply because there is no evidence that something exists, it does not follow that it does not exist? In the Middle Ages, there was no evidence that there were microbes, nor that there were bodies we now call Pluto or Neptune. But they existed nevertheless.

[wiploc]

Since I don't know a thing about oceanography, I hate to be the one to break the news that sea-bottoms are where pearls actually grow.



* P1. If there's not sufficient evidence to believe in X, then it is reasonable to assume that X does not exist.

That's self-refuting. Consider a box of unknown contents. Shall we believe there is a pearl in the box? According to P1, if we say, "X = pearl in the box," then we should believe that there is no pearl in the box. However, also according to P1, if we say, "X = the contents of the box don't include a pearl," then we should believe the pearl is there.

So, according to P1, we should believe that the pearl both is and is not in the box. Thus, P1 is false.

crc

[trendkill]

Was your response credible? I forget.Um, shouldn't you be the judge of that? I really hate when people try to dispute me without actually paying attention to what I say. That is not what I would call debating in good faith.

Yes, it was credible. And not overly verbose. So perhaps you should read it. :P

But isn't it clear that simply because there is no evidence that something exists, it does not follow that it does not exist? 1. Sure. 2. Why direct that question towards me?

:huh:

[trendkill]

So, according to P1, we should believe that the pearl both is and is not in the box.
That is not a necessary implication of P1. P1 only judges whether propositions are reasonable, it does not judge whether they are exclusively worthy of belief. For instance, it may be that both of your pearl-related propositions are reasonable. They can't both be true, but it can be reasonable at times to believe something that turns out not to be true, depending on the evidence available.

[chapka]

* P1. There is not sufficient evidence for me to believe that God exist.
* P2. Therefore it is reasonable for me to assume that God does not exist.
* P3. Therefore I assume God does not exist.
* C1. God does not exist since P => P is true and P = "God does not exist" from (3) above.

I assume I'm the tallest person on IIDB. Therefore I'm the tallest person on IIDB.

See the logical flaw with this? You have the same problem getting from P3 to C1.

Also, P1, P2, and P3 together are basically a tautology. P1 can be simply restated as, "I don't believe in God." So can P2 and P3. So we have:

P1. I don't believe in God.
P2. I don't believe in God.
P3. I don't believe in God.
C1. God doesn't exist.

Also, just as a formal note, "therefore" appearing in the front of what's meant to be a premise is a good sign that you may have a circular argument going. "Therefore" appears between your premises and your conclusions. If you have it at the beginning of P2, you need to unpack your suppressed premises. Unpacking them would reveal the unstated but syllogistically necessary suppressed premise between your P3 and C1: "If I assume something doesn't exist, then it doesn't exist."