I have to disagree there Mordecai. Vader simply puts 2 and 2 together at the end of ANH.
As the X-wings and Tie Fighters are zooming through the channel of the original Death Star
Vader "The force is strong with this one"
After ANH, Vader has to have figured out the Kenobi simply hid his son from him, since as stated in a previous post, that once Vader is completely and thoroughly turned to the dark side, no more force sensitive beings are born.
I've never believed that line 'The Force is Strong with this one' meant anything other than Vader commenting on this person's apparent luck/skill in evading his fire. If he really thought he had run into a Jedi potential I think he would have exclaimed rather more than that.
After Commander Skywalker is hailed by the rebels as a hero after ANH, of course... THEN he can put it all together.
Ushgarak, if he felt that the force was strong in him, thats a giveaway.
if the force is strong in someone, then they have jedi potential.
plus, vader knows as well as ben that there is no such thing as luck.
also, vader is "the best starpilot in the galaxy", so to evade him exhibits extraodinary power with the force.
vader can see that luke knows his moves before they happen, thus precognition, thus he's force-sensative.
either that, or vader felt the presence of kenobi.
or both...
either way, he felt the force at work in those events.
We have never seen any evidence anywhere that you can just 'feel the force' in someone. Vader feels Kenobi's mind because he has felt it so often before but feels nothing from Luke at the time, despite his potential; Qui-Gon guesses it in Anakin from his actions and reactions (and that he feels the Force brought him there for a reason).
It's not what Vader meant. He meant the guy was skilled/lucky. "May the Force be with you," people say in Star Wars- meaning, good luck! If the Force is 'with you', you do really well! Not necessarily a comment on someone's Jedi powers.
And the whole point is that it is what you and I would call luck- he calls it the will of the Force. They replace luck with the vagueries of the Force.
I am certain- Vader would have sounded a LOT more surprised than he was if he thought a Jedi potential was in that ship.
Listen to his tone of voice! It's not "Bloody hell, a new Jedi!" The tone is "Hmm, this one is proving a bit tricky..."
"a tremor in the force, the last time i felt it was in the presence of my old master"
the tremor and obiwan are seperate in that sentence.
when another who is powerful in the force is around vader, he can feel the force in them.
EDIT> plus, you are born with power in the force, but it takes much training to hone in on that power and be a jedi...thus vader doesn't assume its a jedi.
but obiwan's presence creates a disturbance in the force.
i read somewhere (i forget) that the force is like a still pond...the presence of one using the force creates a ripple, which is what other force-users sence. not the person, but the disturbance.
if not, vader would not have felt the tremor and later realize it was kenobi.
fact is, he first felt the tremor in the DS hangar, then went off to meditate on it.
if he sensed ben's presence, and his identity, he would have stormed the Millenium Falcon and tore it apart looking for him.
Anakin = Jesus. Whether GL's influences stemmed from earlier mythologies or not, his man inspiration, and given time I can quote this, is from the christian belief structure. The whole fallen Jedi's becomming Sith ressonates the Paradise Lost fall from grace depiction. Either way, whether the intention was there or not, Anakin becomes a Jesus like figure; Jesus being the most recognizable of the draws, and one that most people can easily see.
Hey hey, its not JUST my view. And cmon now, myself and others have already made the points to back it up, so you just gotta see whats going on. Im not trying to tear apart SW like the Matrix was, but the blatant similarities make for some interesting discussion. haha, yeah, it does sound rediculous, but oh well