Please explain #1. I'm not sure what you're talking about. I agree with #3 and #6, but I thought Jack's dad was dead.

Here's a consensous from "the water cooler" at work:

1. The Others are actually a Dharma research team.

2. They were researching a new virus and things went out of control. They are looking into a vacine which does not work very well on adults - which is why Desmond repeatedly took it - but if injected in someone young it could make them imune. The younger the better.

3. They in some way, shape or form caused the crash. And they specifically chose that flight.

4. The island's security system can detect if a person has the sickness and if they do, it kills them.

I don't really buy #4, that was a "wild" theory.