Did Desmond intentionally lie to Charlie?

Question

In Lost season 3, when Desmond tells Charlie about another vision where Charlie drowns,

he tells him that he also saw Claire boarding the helicopter with the baby. As we see later, Claire doesn't leave the island and Kate takes Aaron with her. Moreover, the baby has already grown up to a kid, so I suppose Desmond would have mentioned Aaron's approximate age if that was the case. (If that is still bound to happen).

So did Desmond lie to him in order to fulfill something else he actually saw there and wanted to happen?

I currently am watching season 4, so if that is explained later (which I doubt because of the last sentence under spoiler tag), I'll take that as an answer to avoid spoilers.

Answer 1

We know that, when Desmond skips around in time and space, he can experience things differently from the way they "really" happened. This is observed multiple times, although it is not entirely clear whether Desmond's experiences are inaccurate, or whether his visits are actually changing the past (or future). However, from Desmond's point of view it does not really matter; he knows that every future he sees is a possible version of what is going to happen.

From what he can see, Desmond knows, however, that some aspects of the future are fixed. Charlie is irrevocably fated to drown on the Island. As long as Charlie is completely focused on staying alive, he can postpone his death, but that occupies all his efforts. Desmond knows that Charlie is not going to keep this up indefinitely, and in the meantime, Charlie is not useful. So Desmond tells Charlie what Charlie needs to hear, that Charlie has the chance to save the two people he loves most by sacrificing himself. Desmond was probably not lying outright; he probably did see a possible future in which Claire and Aaron escape, but he knows that that was not the only possible future. Desmond just did not emphasize to Charlie that things might not turn out that way, because that would not be the most effective way of raising Charlie's morale.