# Is Circular Reasoning ever Good?

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3. » Is Circular Reasoning ever Good?

Thu 20 Nov, 2008 10:53 pm
Just wondering if there is ever a conception that through circular reasoning is valid or whether circular reasoning will always automatically invalidate the statement.

Is this statement circular? Justice <--> Sanity <--> Virtue

What is it about this statement that makes it incomplete, logically absurd, irrational, or flawed in any way?

paulhanke

Thu 20 Nov, 2008 10:59 pm
@Holiday20310401,
... I think that if you make a claim and proceed to prove it using circular logic, that does not mean that the claim is invalid - just your logical proof ...

kennethamy

Fri 21 Nov, 2008 08:36 am
@Holiday20310401,
Holiday20310401 wrote:
Just wondering if there is ever a conception that through circular reasoning is valid or whether circular reasoning will always automatically invalidate the statement.

Is this statement circular? Justice <--> Sanity <--> Virtue

What is it about this statement that makes it incomplete, logically absurd, irrational, or flawed in any way?

Nothing I can see. What makes you think it is circular, though?

A circular argument would be:

1. The Bible is God's word.
2. The Bible states that God exists.

3. Therefore, God exists.

It is circular because premise 1 assumes that 3 is true.

I have never heard of a circular statement, though.

kennethamy

Fri 21 Nov, 2008 08:40 am
@paulhanke,
paulhanke wrote:
... I think that if you make a claim and proceed to prove it using circular logic, that does not mean that the claim is invalid - just your logical proof ...

But "your" proof may be invalid. The fact that it is your proof makes it no more valid, than the fact that a statement is your statement makes it true.

You cannot argue that if you say that moths turn into butterflies, and then when someone replies, "that isn't true", that "Well, it is my statement".

paulhanke

Fri 21 Nov, 2008 08:48 am
@kennethamy,
kennethamy wrote:
You cannot argue that if you say that moths turn into butterflies, and then when someone replies, "that isn't true", that "Well, it is my statement".

... when I said "that does not mean that the claim is invalid - just your logical proof" I wasn't arguing that the claim was automatically valid - just that it was not automatically invalid ...

kennethamy

Fri 21 Nov, 2008 08:52 am
@paulhanke,
paulhanke wrote:
... when I said "that does not mean that the claim is invalid - just your logical proof" I wasn't arguing that the claim was automatically valid - just that it was not automatically invalid ...

No claim is automatically false just because it is someone's claim. And no claim is automatically true just because it is someone's claim.

jgweed

Fri 21 Nov, 2008 09:19 am
@Holiday20310401,
A circular argument is one in which "proof or evidence involving premises which assume the conclusion which is to be established."

It is not a matter of logical validity here, but more an "informal" fallacy in an argument. Usually circular arguments are very complex and not at all immediately obvious because of the use of synonyms in the terms (another informal fallacy called "accent" rampant on these forums) that hide the fallacy. A common circular argument is that the Bible must be true because it is the word of God [and God would not lie to us]; this turns out to be a tautology: the Bible is the Word of God because the Bible is the Word of God.

Here is another example (suggested by Copi, Intoduction to Logic. 2nd edition, 1961):

One argues that Shakespeare is a greater writer than Ayn Rand because people with Good Taste in literature prefer him. If asked how one determines who has Good Taste in literature, one replies that they are identified by preferring Shakespeare to Rand.

Circular arguments are a form of petitio principii, or 'begging the question.'

kennethamy

Fri 21 Nov, 2008 10:00 am
@jgweed,
jgweed wrote:
A circular argument is one in which "proof or evidence involving premises which assume the conclusion which is to be established."

It is not a matter of logical validity here, but more an "informal" fallacy in an argument. Usually circular arguments are very complex and not at all immediately obvious because of the use of synonyms in the terms (another informal fallacy called "accent" rampant on these forums) that hide the fallacy. A common circular argument is that the Bible must be true because it is the word of God [and God would not lie to us]; this turns out to be a tautology: the Bible is the Word of God because the Bible is the Word of God.

Here is another example (suggested by Copi, Intoduction to Logic. 2nd edition, 1961):

One argues that Shakespeare is a greater writer than Ayn Rand because people with Good Taste in literature prefer him. If asked how one determines who has Good Taste in literature, one replies that they are identified by preferring Shakespeare to Rand.

Circular arguments are a form of petitio principii, or 'begging the question.'

The main logical point is that circular arguments prove nothing since they already assume that is to be proved. No one would accept the conclusion of a circular argument who did not already accept the premises.

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