The Wife of Bath was both a seemingly out-of-place woman of liberation in the medieval setting and a sadly weak person who relied on twisting facts and scripture to justify her questionable practices.
I would imagine that women were not treated the same as men in the early years of the 2nd millenium. Only less than a hundred years ago did women begin to get the respect they desired. I would have thought that in the times of the Wife of Bath, wives would've basically submitted to their husbands, or else face punishment.
Such is the case when the Wife of Bath tore a page out of a book her fifth husband owned. "By God, he smote me on the ear, one day, because I tore out of his book a leaf, so that from this my ear is grown quite deaf" (lines 640-642). I would have thought that in her right mind that she would've never done something like that because she supposedly loved him so much.
She does make a good argument in the beginning where she talks about the fact that she has had five husbands and how that fact has been looked down upon by men. She says that some men have had their fair share of wives too. "I know well Abraham was holy man, and Jacob, too, as far as know I can; and each of them had spouses more than two; and many another holy man also" (lines 61-64).
She presented some facts about her that would apply to most people nowadays. For instance, she loved her fifth husband so much that she didn't care about the beatings she got from him. She definitely wasn't completely sane, but not completely insane...she was somewhere in the middle.