There is a tremendous lot of nonsense being bandied around about Desmond, his abilities, and tying together timelines and/or jumping from one to the other. Let's be clear exactly on what Desmond has demonstrated that he can, and cannot do.
What Desmond Can Do
- In Flashes Before Your Eyes, shortly after the hatch explosion, he appears able to see some small way into the future to Charlie's demise, and is able to do things himself to prevent it; however in the long run he was NOT able to change things.
- In Flashes Before Your Eyes he appears to have the ability to revisit memories from his past and change them. I say "appears" becuse we have no idea whether or not he is remembering the past, using an ability to foresee the near future, and change it like he did with Charlie. He appears to have NOT bought the ring in one iteration, but bought it in another; however, that fact could also be explained by Hawking's reading of Faraday's diary, and she knew that Desmond was on the island, was Faraday's constant and therefore inferred that he never married Penny. In any case, in this situation, Desmond does not actually succeed in changing the future. In the only other place in Flashes Before Your Eyes, where he appears to have foreknowledge of the future, he misremembers the night that Jimmy hits the barman. In this case, he takes the hit instead of the Barman. This is very like what happens when he tries to save Charlie.
- In The Constant, Desmond does appear to change the past. In one of his memory episodes he visits Faraday and tells him a message to set his instrument to 2.342, 11 Hertz. This appears to be new to Desmond, but we have no idea at all whether this is new to Faraday; i.e. Faraday was attempting to reconcile a possible paradox; he knew that Desmond visited him, but Desmond did not.
- In Because You Left, Faraday knocks on the Hatch and tells Desmond a message. Desmond wakes up in 2007, and remembers the message, even though it actually occurred some 3 years earlier. We are meant to infer from this that Desmond's memories can be altered by someone in his past changing an event which occurred.
In summary, Desmond's abilities appear to be:
- A limited, uncontrollable and ultimately ineffective ability to see into the future. This seemed to have been temporary and directly related to the hatch implosion, and specifically Charlie-related.
- An ability under certain circumstances, to revisit memories from his past and attempt to change these. Again, these were mainly ineffective, although there was one instance where a significant change may have occurred.
- An ability to recognise when events relating directly to him have been changed by others when time travelling. These appear as "new" memories.
What Desmond Cannot do
- There is no evidence whatsoever that Desmond can time travel. other people have time travelled, but not Desmond. All of his apparent time travellings have been changes to his memory.
- There is absolutely no evidence whatsoever that Desmond has ever "remembered" events common to both FST & OT, let alone jumped from one to another. On the plane in LA X, Part 1, Desmond did not recognise Jack; it was vice-versa. In Flashes Before Your Eyes, Hawking, Faraday and Widmore are all the people from the OT. Desmond is a character from the OT; if he had originally been an FST character, he would never have ended up on the island in the first place, as it does not exist in the FST. This would have required all of Desmond's history prior to the ring shop to have been FST, him to have not bought the ring, and decided not to marry Penny, but that Widmore still exists in the FST, Desmond to go on his yacht race, and somehow not only find the island, but jump through the reality barrier into the OT. However, what then happened to the original OT Desmond, was Libby who gave him the boat an OT or FST character?
What Does Widmore Know of Desmond's abilities?
- If Desmond told Penny, and Penny told Widmore, then everything. This is a stretch, considering that Penny & her father had been estranged.
- Hawking will have known about the ring shop, and Desmond attempting to change his future. She would also have known that ultimately, his attempts were futile.
What exactly is Widmore trying to get Desmond to do?
Widmore can only know second hand, what Desmond's abilities are. The fact that Widmore is searching for EM pockets suggests that he knows that Desmond's abilities are tied specifically to EM bursts. Given the above, the following possibilities remain:
- To use his abilities to see into the near future in an attempt to circumvent what MiB is trying to do. If this is the case, then Desmond would have needed to have told Penny about the Charlie incidents, and Penny told Widmore.
- To use his abilities to reach into his own memories, change them so that some crucial event (e.g. failing to push the button, or detonating the hatch did not occur).One possibility here is that he is trying to re-engineer events so that Hawking does not shoot their son, Faraday.
Realistically (1) seems less likely than (2). It is not really credible that Widmore drags him out to the island on the off chance that he can replicate the Charlie stuff with someone else, especially when it did not actually succeeed in the first place. (2) is a much better proposition; there is evidence the Desmond can reach into his own memories, change things and make those changes stick. My bet is on this scenario. Widmore would not be doing this for anything trivial, as he would need to blow up a pocket of EM with Desmond on top of it. This is high risk. Widmore is trying to change an event in Desmond's life which is crucial to the history of the island. In the three years he was on the island there were two events which qualify: (a) failing to press the button and crashing O815, and (b) detonating the Swan Hatch. If it is (a), then Widmore is trying to re-engineer time so that none of the events of O815 occured at all , including presumably Ben getting dunked in the temple pool, taking over from him. In that respect, he is attempting to do exactly what Jack, Juliet were doing with Jughead in 1977. That means Jack et al. should be on team Widmore. If it is (b), then Widmore is trying to stop all the events which occurred post hatch implosion, including all the O6 return and the timetravelling antics, but leave Jack et al. on the island. It is very difficult to see what Widmore would gain by all this, as it leaves him off the island, not knowing where it is. (He only found the island due to the EM explosion)
Anyone want to take a gamble that once this is all explained to Jack, he wants to go for it hell for leather? Sawyer would; it would bring back Juliet, cure Sayid, release Claire, unkill all the O815 and A316 dead as well as all those in the Temple. What's not to like about the plan?
Unfortunately, what Widmore is unaware of, and we are, is the extent to which the time-travelling has infected the timeline through & through. Undoing it is potentailly catastrophic.