Well if someone is pro-gun and their brother is murdered for no reason by someone with a gun and that changes their attitude, it's understandable, they got new information that changed their opinion, it happens all the time with some of us.
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"This will be a fight against overwhelming odds from which survival cannot be expected. We will do what damage we can."
-- Capt. Copeland
Or maybe just maybe you were stupidly biased before and your exposure to new realities made you feel that hey maybe my original position was wrong.
You have almost literally no idea what bias is apparently.
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He didn't say it was an argument please learn to read.
“Logic: The art of thinking and reasoning in strict accordance with the limitations and incapacities of the human misunderstanding.”
"Conservative, n: A statesman who is enamored of existing evils, as distinguished from the Liberal who wishes to replace them with others."
Ambrose Bierce
The Bird of Hermes Is My Name, Eating My Wings To Make Me Tame.