A valid argument is often defined as one in which it is not possible for all the premises to be true and the conclusion false. A circular argument is sometimes defined as one in which one of the premises is identical to the conclusion.

From these definitions we can infer that...

(A) Every circular argument is valid as long as its premises are true.
(B) Every valid argument is circular.
(C) No circular argument is valid.
(D) Some circular arguments are valid, and some are not.
(E) Some circular arguments are not valid, and some valid arguments are not circular.

So, in a circular argument, if the premises are all true, the conclusion must be true: the conclusion is the same as one of the premises.



Since the conclusion of a circular argument is the same as one of the premises, if the premises are all true, the conclusion cannot be false. Thus, circular arguments are 'valid arguments', according to the definitions. A.
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A circular argument is sometimes defined as one in which one of the premises is identical to the conclusion.


So, in a circular argument, if the premises are all true, the conclusion must be true: the conclusion is the same as one of the premises.

durgesh79 wrote:
A valid argument is often defined as one in which it is not possible for all the premises to be true and the conclusion false.


Since the conclusion of a circular argument is the same as one of the premises, if the premises are all true, the conclusion cannot be false. Thus, circular arguments are 'valid arguments', according to the definitions. A.


So, in a circular argument, if the premises are all true, the conclusion must be true: the conclusion is the same as one of the premises.



Since the conclusion of a circular argument is the same as one of the premises, if the premises are all true, the conclusion cannot be false. Thus, circular arguments are 'valid arguments', according to the definitions. A.

Hi,

Shouldn't the above explanation also make option D right. ?
D. Some circular arguments are valid, and some are not.

I think the answer should be A.

From the question, "A valid argument is often defined as one in which it is not possible for all the premises to be true and the conclusion false." There is nothing in this definition to suggest that false premises make an argument invalid.
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That is not a valid inference. While the question doesn't say that there are only two values the premise and conclusion can take, it doesn't make a difference if we assume this to be the case. An argument is valid if:

If the premises are true, the conclusion is true.

The lone inference we can make from this is the contrapositive (from "If A then B" you can always conclude "If not B then not A"). That is, we can conclude:

If the conclusion is false, the premises are false (well, at least one of them is).

The inference you have made, "If the premises are false, the conclusion is false", is called the 'inverse'. That is, you've translated "If A then B" into "If not A then not B". This is not a legitimate inference to draw, as I will illustrate with an example. Suppose I'm standing next to a swimming pool, and have no shelter nearby. Then the following may be true:

"If it rains, I get wet."

We can certainly deduce the contrapositive:

"If I'm not wet, it's not raining."

We cannot conclude the inverse:

"If it's not raining, I'm not wet". I might be in the swimming pool.

Equivalently, we cannot deduce the converse (I say equivalently, because the converse is the contrapositive of the inverse- they're logically the same):

"If I'm wet, it's raining." Again, I might be swimming.
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Good discussion Guys, the OA is A. Below is the OE, which i dint understand.

"(A) Some people find this paradoxical, but it follows directly that circular arguments are valid. If the premises are true, and the conclusion is one if the premises, it must be true. Another trick here is the word 'valid'. Just because an argument is valid, does not mean it is true. Many people will make that false assumption and be thrown off on this question."

took long time to understand this. But agree with A.

Valid argument --> Often, all premises cannot be true, conclusion cannot be false
Circular argument --> sometimes, premise = conclusion

(A) Every circular argument is valid as long as its premises are true.

If premises are true --> conclusion is true (Circular argument) --> and conclusion cannot be false in valid argument --> In this case, conclusion is true and hence circular argument is valid as long as its premises are true.

+1 for A. But a good challenging CR Thanks durgesh79

+1 for A