The detonation of Jughead did NOT create an alternate reality by Magnus Hanso

Despite the fact that we see the Losties back on 815 (along with Desmond and the real Seth Norris), I do not think that what we are seeing is what we've been lead to believe by Daniel -- that it is an alternate reality of some kind that was created when Jughead went off.

The reason I don't think that an alternate reality would be created because of a different decision made in the past is that, if this were the case, we would have to assume that there are infinite alternate realities. If the universe works in such a way that an opposite decision (or different random outcome) in the past causes an alternate timeline to be created, then every single decision/random outcome from the beginning of time would have created an alternate timeline as well, and there would be an infinite number of alternate timelines occurring simultaneously -- one for every possible past outcome. Saying the universe decides when to split off into an alternate timeline and when not to based on the "impact of the event" would not really compute, at least not to me.

If the writers are going down a path where different past decisions cause alternate realities and everything that could ever possibly happen has happened in at least one reality, that sure doesn't make for a very exciting ending. Whatever happens at the end, the opposite of that happened too, and so did everything in between in some unseen reality or another. You couldn’t even say that in every possible timeline mankind is destroyed and Jacob is trying to prevent that, because such a universe would include all possible outcomes and in some realities mankind would never exist, would never have advanced to the point of being able to destroy itself, etc.

I think the writers are doing and have done a fantastically good job of sending us chasing after wild geese and gazing at red herrings. If we are in fact seeing an alternate reality, which is entirely possible, it had to have been created by some other means (electromagnetic energy) than by making a different decision in the past, such as turning the Frozen Wheel or the Swan fail-safe incident that caused Desmond to start flashing between two “realities” or “timelines”.