Is Peter from the other side??*SPOILER ALERT*

Yes, I do believe that he is from the other side of the barrier. I think I think happened is that he died in this universe (I remember Walter Bishop saying that he almost drowned, so drowning is probably how it happened), then Walter opened up a rift and stole the other universe's version and brought him here.

Before I saw the tombstone at the end of the espisode, I thought that perhaps Peter was from the other side. When I saw the woods, I asked my wife if this wasn't the area Peter almost drowned in as a kid (the wife was no help). Then when Walter started to talk about losing something and opening up a rift (or whatever term he used), I became positive that he was talking about Peter.

For me, the tombstone at the end of the espisode merely confirmed (in my mind) what I thought was happening.

Now the interesting part is that Walter Bishop and the character played by Nimoy (I forgot the name of the character) may be the ones responsible for everything (rift-wise) that is happening. They may have been the ones to open up the rift in the first place.

ha ha morgandrake took the words from my mouth. I would have said that walter took peter from the other side but there's no point now. Anyways if you want to know another piece of evidence this is a really small one. In the episode the inner child peter was playing with the white kid and action figure he mentiond that he rememberd the scar of the action figure to be on the other side....anyways the next season will definitly prove it if the gravestone didnt prove enought lol.