I could be wrong, but I'm just going to throw this out there. If the Bible is right on some things about God, man, sin, heaven and hell, etc., but wrong on other things, then isn't every religious book like the Bible? In fact, isn't everything like the Bible?
Let me demonstrate by listing off various books that make statements about God, man, sin, etc. that are sometimes true and sometimes false.
The Book of Mormon
The Bhagavad Gita
Science and Health with a Key to the Scriptures
A Course in Miracles
The Satanic Bible
But here are a few more books of that nature:
The works of Shakespeare
The Left Behind Series
Songs are capable of speaking about God in both erroneous and true ways.
Speeches do it. Screeches do it. And even fuzzy leeches do it (had to get my "Seuss" on there ;-))
In fact, all of my works can be said to accomplish this. All of your writings can be the same. In short, if the Bible is just a book made up of truth and error, then isn't that what every book is? Isn't that what our own thinking is? How is the Bible better than any other book then? How is the Bible better than our own thinking? Doesn't that make the authority of the Bible the same as any other book? Doesn't that make the authority of the Bible the same as the authority of our own opinions?
If not, why not? Is it the ratio of error to truth in the Bible? How does one go about figuring that out?
And if the Bible is the same as all of these other books in that regard, doesn't this view of the Bible really mean that biblical religion is just as prone to be true or false as any other religion? As our own religion if we should choose to make one up?
Doesn't errancy then essentially logically lead into inclusivism? What's wrong with Hinduism or Islam if they have both truth and error in them? They both incorporate a Jesus in their religions, not the biblical Jesus, but the Bible is wrong on Jesus sometimes anyway, right?
Maybe I'm missing something, but maybe errantists are truly liberals, despite the protest of people like Bovell who want to create the idea that there is a middle ground. Perhaps errantism is liberalism because it can't be anything else if taken to its logical conclusions. But if that's the case, I'm not sure why the Bible is anything more than a man's particular flavor of the month. The Book of Mormon would do just as well, or better yet, just listen to some music, secular or religious, as it's all bound to get around to some truth at some point.
If theological and ethical errancy does, in fact, logically necessitate inclusivism, then the Bible or the Bible's religion is no more necessary to believe than any other man's book and religion, or any other man's ideas for that matter.
In short, it would seem that theological and ethical errancy is nothing short of apostasy and unbelief. It is a denial of the faith of the Bible, not just a different version of the same faith. This would mean that we are not brothers with errantists, but mortal enemies.