Prediction and foretelling are not the basic thought behind the Hebrew
na-va' and the Greek
pro-phe-teu'o translated into English as prophesy. When Ezekiel was told to 'prophesy to the wind' he simply expressed God's command to the wind. (Eze 37:9,10). So at it's very basic meaning it means to 'tell forth' God's mind on matters. Because of this, we (Jehovah's Witnesses) are rightly all prophets, not just a few. We all have the commission to preach the 'good news of the kingdom." (Mt 24:14; Mt 28:19,20) Still we do not say anything new, in the sense that we do not produce any newly inspired writings. We are convinced that the 66 books of the Bible are the last of the inspired writings until after Armageddon when the new "scrolls" will be opened. (Re 20:12)
Our authority is the Bible and the Bible only. And it is our understanding of it that grows and changes as we get deeper and deeper into "the time of the end." (Da 12:4) Because our understanding gets deeper sometimes we have to reevaluate what we once thought was true. Regardless we keep doing what our Master (Jesus) directed: Keep the focus on God's Kingdom. Teach people how to be good citizens of it.
There have been many refinements over the years. But certain core beliefs have been very stable since the very beginning of our modern day development. One of
@katiemygirl's primary complaints is that we do refine our beliefs. She takes it as a sign that we are, or our organization is ran by, false prophets. I disagree. To me it is a sign of humility that we can eat our words without giving out when our understanding is corrected by Jehovah. We adjust. We adapt. It does not seem like it so much on the forum, but that is because we have left behind many of the teachings brought up on this forum a very very long time ago, with no evidence that convinces us that we were wrong to do so.
Kate is still trying, and I do admire her effort, to demonstrate that we were mistaken. We may not agree on these matters, but she does have a zeal that Paul had.