Nah it was the island that was real and the other stuff was 'limbo' for want of a better word. Hence the line about some characters dying long after Jack.
I agree with wjp, you could say well there was this electromagnetic thing and that could heal/stop babies being born etc. (with a rather scifi hat on at least) - but numbers, dharma projects, loads of other things which make a lot of the series feel pointless.