But that is the TRUTH. Truth is not circular.
Circular refers to the sort logical argument you are using. A circular argument is an invalid argument. It's a fallacy.
It doesn't meant that your premises or even you conclusion are not true, it just means that your argument (the way you arrived at your conclusion) is invalid. You can't (or shouldn't) use it to prove your conclusion.
Let me rework the argument you gave, to make it absolutely logically valid.
premise and truth: the KJV is the word of God
Okay, in order for your argument to be airtight, this is going to have to be changed to this:
The KJV is the only word of God.
examination : others are not because they ALTER the word of God.
This'll have to become
Modern versions are not the KJV
conclusion: the modern versions are not the word of God
Yep, as long as the first two statements are true (and I assume you believe them so) then that conclusion is valid. The argument is airtight
as long as the premises are true
Premise #2 gives no problems. I assume everyone here would agree with that.
The problem is with premise #1. What argument do you give for it? How do you know it true?
If you say, because I know it's true", that's a circular argument. Its basically saying, the KJV is the only word of God because the KJV is the only word of God.
If you say, "because the Holy Spirit told me", then you are using very subjective proof, and proof that can't be known by anyone but you. (This is where the gnostic charge comes in. This seems awfully close to claiming "special knowledge" as proof of truth.)
If you say, "because God's word tells me it's so", then you are going to have to come up with the statements from scripture that support the KJV being the only word of God. If you can, then you've got good objective proof that your starting premise is a true one, and I'd bet that no one here would argue with you then.
So if you want to make a valid argument, that's where your going to have to concentrate your effort. Finding scriptural proof that the KJV is the only word of God.
All the other stuff doesn't help you at all, because it doesn't help you make a VALID argument.