First off props to the_phoenix13 for help with this idea.
I think that Jacob is the result of a failed time travel experiment. Faraday was trying to send a rat's consciousness back in time; not its body, but its mind. I think this is the same time travel Desmond experiences; his consciousness jumps to different time periods but his body doesn't jump with him, he just switches minds. That's why he couldn't remember anyone's name when he was on the freighter after the helicopter ride.
Now what would happen if your consciousness time jumped to a period where you didn't have a body to inhabit? Like before you were born? I think the result would be Jacob. A "consciousness" stuck without a body, but still perceptible by certain individuals! The only question now for me is who was the subject of the experiment? Or could it be Desmond himself mistiming a jump? Theory by ivey_driveshaft
I think that Jacob is the result of a failed time travel experiment. Faraday was trying to send a rat's consciousness back in time; not its body, but its mind. I think this is the same time travel Desmond experiences; his consciousness jumps to different time periods but his body doesn't jump with him, he just switches minds. That's why he couldn't remember anyone's name when he was on the freighter after the helicopter ride.
Now what would happen if your consciousness time jumped to a period where you didn't have a body to inhabit? Like before you were born? I think the result would be Jacob. A "consciousness" stuck without a body, but still perceptible by certain individuals! The only question now for me is who was the subject of the experiment? Or could it be Desmond himself mistiming a jump? Theory by ivey_driveshaft