Walt was a subject of an experiment by the dharma group that involved brain waves and imagination. They injected him with something when he was a little kid. Whatever they did to Walt gave him the power to bring his visual thoughts to reality and the dharma group purposely crashed the plane to bring him (and everyone else) there for further testing. The "others" work for the dharma group and tracked down walt to bring him in.

Kind of a weird theory i know but its all I could come up with. Im not saying there aren't any holes in it, but i think its possible. Let me know what you think.

__________________
\"We\'re not alone on this Island and we all KNOW IT\" - John Locke

Locke: Why do you find it so hard to believe?
Jack: Why do you find it so easy?
Locke: It\'s never been easy.