Re: "Learning Aikido by Watching Aikido Video"
Learning martial arts from a video.
Well, you can probably get a great overview of Aikido from a video. It would probably teach you to memorize the names of the techniques, so you could regurgitate the name when you see said technique.
It could probably teach you to recite what ever philosophy the tape maker has on Aikido, and you could regurgitate that as well. If you studied the tape well (and it's a good tape) you could probably get as far as 70% percent of the normal class going Aikidoka get-memorization and regurgitation.
However you're never going to learn anything physical like a martial art by just watching. It's going to require you to train with a friend to actually learn how to move. It is also very helpful to have an experienced person there to see your personal problems and talk you through them. You're never going to learn to apply Aiki (or Aikido technique) unless you actually do it, watching is only concept.