Min,
It all depends on what level of witnessized the person is. It doesn't depend on their level of intelligence as much as it depends on their level of open mindedness and having the ability to be truly honest with themselves. If they have completely succumb to the JW teaching to close their minds to any thought or concept not directly given to them by the manipulation of the cult, then trying to reason with them is useless. Witness or not, you cannot reason with ignorance or a completely closed mind.
If a JW can ever listen to themselves when they say they like or dislike something, agree or disagree with something, and then try to determine whether their response is based on JW teaching or their TRUE personal opinion, then they may have a chance. That is where being truly honest with themselves comes into play. That is the essential ingredient for any person to become self aware and a true individual.
The JW leaders know that. That is why they hound their followers with the dangers of independent thinking. They convince them it's the evil Debbel talking to them. The weak and feeble minded buy into that crap and hide behind the pseudo security of collective thinking. The ones who have the ability to see the truth about anything in life keep using their brains to eventually figure it out and begin to see things from a more honest and truthful perspective.
Watching your progression on this board from day one, you are a prime example of the latter.
Dave