People decide first what view to espouse. That's step # 1.

They then set about explaining, in what they feel is a totally reasonable fashion, why it is obvious that their view is the right one.

And they could just as well have chosen the opposite point of view, in which case they would be arguing with equal confidence from that angle.

And 5 years later, they may indeed be espousing the opposite view, and have forgotten that they once opposed it.

Any thread on the 911 conspiracy theories is a perfect example of people's utter capriciousness and inflexibility in this regard. If you read the discussions dispassionately, and with a degree of humor, you can immediately see that everyone (probably including yourself) has...

#1 - Made up their minds already that their viewpoint (whatever it is) is the only right one, the only one that can be right...and that that is bloody obvious to anyone who doesn't wear a tinfoil hat.

#2 - Set out to examine all the available evidence they can find, which evidence PROVES... to their delight, yes, it PROVES that they are dead right! (no matter what it is they think) And it proves that their opponents are illogical idiots who refuse to look at "the facts". ;-)

#3 - They then watch like hawks for those "idiots" to dare to contradict them, in which case they will have another good excuse to show how brilliant they are by refuting those opponents' pitiful arguments...

You know what it adds up to? Nothing but a big, empty battle of windbag egos. But it gives those restless minds something to do, doesn't it?