Lost: spoiler alert!

If you haven't yet seen up through 2x03 "Orientation", finish watching, then come back here. As I write this, I've also seen 2x04, but it doesn't change any of my theory, nor do I spoil that episode.

There are several unexplained things that have been happening on the island. Maybe some of them can be tied together... I now have a theory that explains some key plot points:

• How Locke can walk
• Why the people in the orientation video were on the boat
• Why Walt was abducted and how he appeared to Shannon in the forest

I'm moving away from the alien abduction theory and going with ... they're
in the Matrix!

How can Locke walk?
"Is it really so hard to believe? Your clothes are different. The plugs in
your arms and head are gone. Your hair is changed."
Locke can walk because he's in the matrix.  He's not burdened by "residual
self image"... he wanted to walk and explore so badly that when plugged
into a virtual reality, he envisions himself without the paralysis.

Same people showing up?
The people in the orientation video who started project Dharma showed up on
the boat and kidnapped Walt... they created the matrix and are free to come
and go as they please.  They came and took Walt... they unplugged him.  The
people who were on the raft (Michael, Jin and Sawyer) haven't seen the
video yet... when they do, they'll recognize the kidnappers and that will
bring them one step closer to realizing that there is no spoon.

Why did they take Walt?
"We have a rule.  We never free a mind once it has reached a certain age.
It's dangerous, the mind has trouble letting go."
Walt is still young enough to have a malleable mind.  They're afraid that
he'll quit believing and wake up.  Apparently, he figured out how to
communicate with people on the inside and sent the message to Shannon (her
hallucination).

This all still leaves the questions of how and why.  Are they still on the
plane?  Were they ever on the plane?  Perhaps they're in a simulator at the
Sydney airport.  What exactly do the numbers mean and why are they in
ascending order?  What happens if they don't press the button?  Will they
wake up?  It certainly doesn't explain everything, but I think it's
consistent and doesn't conflict with anything we've seen so far.