Whilst it could be argued that time travel kills any suspense in a drama by acting as an all-purpose reset button (see Hiro Nakamura), a huge number of novels, movies and TV shows have confidently handled time travel by sensibly establishing rules. These rules usually follow the lines of:

Don't attempt to meet yourself (Cosmic feedback will occur) Don't attempt to benefit from future knowledge (Bad ju-ju will ensue) Don't kill your own Grandfather (Like, duh!)

In the mythos of Lost, the established rule is namely "Course Correction", or as Doris Day would put it, Que Sera, Sera.

Now, here's the rub... If we swallow the theory of Course Correction, everything that has, is and will happen is meant to be - and where's the fun in that? Not only is the concept of predestination a joyless prospect to contemplate; when it's combined with time travel to the past, it renders every action of the time traveler to be paradoxical.

E.g.: Your "current" activity whilst visiting the past hasn't altered the past, because you always were in the past at that point.

Yes, it's still a theoretically-solid example of time travel, but it's also somehow unrewarding...

We've grown-up with Back To The Future, Star Trek and Doctor Who. That's how we like our time travel to be! We know that if we stand on an bug, it will never have bitten somebody's arm whilst they were driving the car which should have crashed into the pregnant lady who later gives birth to the evil guy who takes over the world. We get that stuff!

So, it isn't time travel per se which has bemused Lost fans the world over, it's the type of time travel on display. We're sat there wondering just how Locke giving Richard the compass; Faraday telling the Others to bury the H Bomb and Frogurt dying before he was even born hasn't changed anything.

Well, don't despair because I have the aspirin for your headache...

Isn't it entirely possible that Ms. Hawking's explanation of Course Correction is wrong? Have we ever witnessed proof that she isn't wrong?

Now, I'm not calling her a liar; but seeing as she's apparently an acquaintance of Benjamin Linus (and Charles Widmore knows her well-enough to have her address)... Well, you can judge a lady by the company she keeps - that's all I'm saying. Damon may /have referred to her as "a temporal policeman", but some cops are bad.

Desmond had several visions of Charlie's demise (prior to Charlie's fatal drowning), after being made aware by Ms. Hawking of the alleged Course Correction rule. Yes, Charlie Pace did die eventually, but don't we all? Perhaps if Charlie had not accepted his "fate", Desmond could have had several more visions of Charlie's death; saving him again and again, right up until Charlie died of old age.

You know, most of the main characters have been in near-death scenarios on the Island - it sort of goes with the territory. Charlie being in constant peril wasn't exactly unusual. In any case, Desmond's visions haven't all yet come true - remember what he told Claire about her leaving the Island? Charlie's death could have been a self-fulfilling prophecy: he sacrificed his life because he believed he was going to die anyway.

Why was Ms. Hawking so insistent to Desmond that he should not buy the ring (to propose to Penny instead of taking part in the yacht race) if Desmond's future on the Island was pre-destined? Ms. Hawking went so far as saying that if Desmond didn't go to the Island, then "every single one of us is dead".

"Ah", you're probably thinking, "But Desmond is special". He's aware of "new" past events, such as his conversation with Faraday in episode 5.02. "He's seemingly exempt from Course Correction (for reasons we can only speculate upon)"... Well, what about Ms. Hawking's exchange with Ben when advising him that he has just seventy hours to return the O6 to the Island?

BEN: Look, I lost Reyes tonight. What happens if I can't get them all to come back?

MS. HAWKING: Then God help us all.

Riiiiight... Why would Ms. Hawking care if Ben "can't get them all to come back"? Does "if" even enter into the supposed laws of Course Correction?

The ultimate verification of whether or not time-travel in Lost would involve free-will or fate would obviously come from the show-runners, Damon and Carlton. In a recent interview, they discussed this very issue and stated that the audiences (and characters) are meant to be questioning whether or not the past can be changed; giving no definitive answer.

How odd then, that on the Official Lost Podcast of February 20th 2007, whilst recapping 'Flashes Before Your Eyes', they definitively stated that: Desmond's original timeline didn't include him getting hit with the bat; Desmond's original timeline may have involved getting the photograph of him and Penelope taken at a different time with two photos instead of one.

So, Desmond had an "original timeline" inferring that he now had an alternate timeline - meaning that the past had been changed. Again, we know that Desmond is special; Penny is his Constant and all the other factors which may exclude him from the rules (yadda, yada, yadda)... But other people were dragged into his new alternate timeline, like his friend Donovan.

The only fly in the ointment is that it isn't just Ms. Hawking whom has posited that past events cannot be changed. Both Daniel Faraday and Pierre Chang have inferred that the past cannot be changed; Faraday blatantly and Chang by dismissing a lowly DHARMA worker's suggestion that they could go back and kill Hitler. There's obviously the possibility that they too are lying.

Faraday may be lying to minimize any major changes to the space-time continuum, so that the left-behinds can eventually go back to their future and Chang... Chang's whole raison d'etre seems to have been the promotion of misinformation.

So, if the talk of causal loops, cyclical time and temporal paradoxes in the forums is scaring you away from posting, don't let it. There's more than enough evidence to suggest that the time travel in Lost is the good old-fashioned bug-stomping-equals-apocalypse kind.