Fallacies: Circular Logic

"God exists. I know because the Bible says so. The Bible is inerrant and true because God wrote it."
-Anonymous Theist

(For more on this subject, see my post on Circular Logic)

A circular argument is one in which the conclusion is assumed beforehand in some manner as a premise. for example:

1. Premise A proves premise B
2. Premise B proves premise C
3. Premise C proves premise A

The argument is only true if you already accept the conclusion. The following is a joke that is a good illustration of similar circularity.

It was autumn, and the Indians on the remote reservation asked their
new Chief if the winter was going to be cold or mild.

Since he was an Indian Chief in a modern society, he had never been
taught the old secrets, and when he looked at the sky, he couldn't tell
what theweather was going to be.

Nevertheless, to be on the safe side, he replied to his tribe that the winter was indeed going to be cold and that the members of the village should collect wood to be prepared. But also being a practical leader, after several days he got an idea. He went to the phone booth, called the National Weather Service and asked, "Is the coming winter going to be cold?"

"It looks like this winter is going to be quite cold indeed," the
Meteorologist at the weather service responded.

So the Chief went back to his people and told them to collect even more wood in order to be prepared.

One week later he called the National Weather Service again. "Is it going to be a very cold winter."
The Chief again went back to his people and ordered them to collect every scrap of wood they could find.

Two weeks later he called the National Weather Service again. "Are you
absolutely sure that the winter is going to be very cold?"

"Absolutely," the man replied. "It looks like it's going to be one of
the coldest winters ever."

"How can you be so sure?" the Chief asked.

The weatherman replied, "The Indians are collecting firewood like crazy."

The weathermen are getting their information from the Indians and visa versa, meaning neither of them has obtained actual reliable information. This is analogous to the story of Immanuel Kant of Königsberg, Russia (Germany at the time). He lived a solitary life of extremely regular habits, like his daily, post-dinner walk. it is said that the citizens of Königsberg set their clocks according to the position of Professor Kant on this daily walk down and back the same street (this street later became know as the Philosophengang or "The Philosopher's Walk"). It is also believed to be true that the sexton of Königsberg Cathedral also confirmed the time on the church tower clock by observing when Kant took his daily walk, and Kant in turn scheduled his walk by the church tower clock! That is the perfect example of a problem caused by circularity. Both Kant and the Cathedral thought that they were obtaining new information by observing the other, when really they were confirming the time in a way such that their times would match up by definition. Just like with circular arguments, both pieces could be wrong, but since they back each other up, there is no external data being taken into account. 

PS: Sorry I disappeared for a while. I had some personal problems to take care of. God punished me for my infidelity by causing my dog to die last Friday, and among other things I've just been busy. I should be back to posting regularly, hopefully almost daily again. c: