Circular logic

[Dragon*of*Heaven]

Why is Circular logic impossible or incorrect?

[droskey]

Circular logic assumes what it aims to proove. Therefore, it doesn't really proove anything. An example of circular logic would go like this:

1.) God inspired the Bible, so it must be correct.
2.) The Bible says that God exists.
3.) The Bible is correct because God inspired it.
4.) Therefore, God exists.

[solidsquid]

The circular reasoning fallacy is also known as begging the question and petitio principii. Jacopo's example is one that you'll run into often in debates on the existence of god.

Here's an example:

In the case of the fallacy of circular reasoning, the difference is not be as obvious as you might expect. In the fallacy of circular reasoning, which is often called begging the question, you assume to be true what you are supposed to be proving. But that's also true for all valid deductions, where the conclusion (what you are trying to prove) is derived from the premises or assumptions. This difference is that, in circular reasoning, the conclusion is contained in a single premise or assumption, while in a deductive argument the conclusion is derived from both premises. Consider the following exchanges:

Deductive Reasoning (Valid)

Sports Fan #1: What makes you say Australian Rules Football is the most exciting sport in the world?
Sports Fan #2: Because it is the fastest and highest scoring form of football, and whatever is the fastest and highest scoring form of football must be the most exciting sport in the world.

Circular Reasoning (Fallacious)

Sports Fan #1: What makes you say Australian Rules Football is the most exciting sport in the world?
Sports Fan #2: Because it is.

In both examples, the conclusion has been assumed in the premises. But the first argument follows a valid pattern: If P (fastest and highest scoring), then Q (most exciting). Aussie Rules Football is P (fastest and highest scoring), therefore Aussie Rules Football is Q (most exciting). But in the second example, the one for circular reasoning, the conclusion has been assumed entirely (or almost entirely) in a single premise. As a result, the conclusion of a circular argument can be seen as just a restatement of its only premise. It's like saying, "A is B, therefore A is B."

Often, however, circular reasoning is more subtle than this: it depends on an assumption not stated but assumed. Consider the famous argument of the French philosopher, René Descartes: "I think, therefore I am." Descartes has begged the question here, because when he said "I think," he'd already implied "I am" (or how else could he think?). Yet his fallacy continues to persuade people, over three hundred years later.

Source - www2.sjsu.edu/depts/itl/graphics/adhom/circular.html

[Dragon*of*Heaven]

Thank you both for your help~^!^~

[vertigo]

Consider the famous argument of the French philosopher, René Descartes: "I think, therefore I am." Descartes has begged the question here, because when he said "I think," he'd already implied "I am" (or how else could he think?). Yet his fallacy continues to persuade people, over three hundred years later.

I tend to think he meant "I think, thereby I come to realise I am", "I know I am because I think". Could you (someone) support the opinion that he meant being requires thinking?

[Hilly]

Often, however, circular reasoning is more subtle than this: it depends on an assumption not stated but assumed. Consider the famous argument of the French philosopher, René Descartes: "I think, therefore I am." Descartes has begged the question here, because when he said "I think," he'd already implied "I am" (or how else could he think?). Yet his fallacy continues to persuade people, over three hundred years later.

Source - www2.sjsu.edu/depts/itl/graphics/adhom/circular.html[/quote]

I'm not really convinced that the above is an example of circular reasoning .

There does seem to be a number of ways of getting at what he meant. How bout, thinking confirms being?

[vertigo]

There does seem to be a number of ways of getting at what he meant. How bout, thinking confirms being?

I think it's more a case of "thinking requires being".

[vertigo]

I have been really busy and stressed out lately, and I gave really shoddy replies here. Let me now correct that.

The statement means 'thought requires being'. It is obviously true. To call it a fallacy is simply wrong. Further, I read that people continue to be persuaded by it. This implies a study over time, while holding this fallacious opinion. I infer that this speaker should not be highly regarded.

I would therefore be more suspicious when reading whatever else they have to say.

Following the speaker's line of thought, I could call these false: 'I am a human, therefore I have two legs' or 'I have brown hair, therefore I do not have blonde hair'. These are perfectly valid deductions.

[Pilgrim]

"I think therefore I am"
It could also be said that I am therefore I think.

I took a ride in a car.
Therefore the car was real.
Therefore the car was designed
Therefore the car had a manufacturer.

[vertigo]

It could also be said that I am therefore I think.

I told you to learn logic. Do it now.

[solidsquid]

pilgrim said:

"I think therefore I am"
It could also be said that I am therefore I think.

I took a ride in a car.
Therefore the car was real.
Therefore the car was designed
Therefore the car had a manufacturer.

....and your point is?

[vertigo]

From my limited understand of his point, I read two things:
1. An 'implies' relation is reflexive.
2. I conversed with God, therefore God was real, God was designed, God had a manufacturer.

[solidsquid]

Ah, a false analogy then.

[Dragon*of*Heaven]

Christians do believe that since they converse with God he must be real. What I ask is this "How on earth is this standing any different than the schizophrenic who believes the voices in his head are real.

[Pilgrim]

solidsquid said:

pilgrim said:

"I think therefore I am"
It could also be said that I am therefore I think.

I took a ride in a car.
Therefore the car was real.
Therefore the car was designed
Therefore the car had a manufacturer.

....and your point is?

The car is evidence of a manufacturer