An odd idea

'The Youngness Paradox' --"Why SETI has Not Found Any Signals from Extraterrestrial Civilizations” 

According to MIT's  Alan Guth , originator of the inflationary universe theory, our Universe is a product of eternal inflation --eternal into the future, but not into the past. An eternally inflating Universe produces an infinite number of pocket universes , which in turn are producing more new universes.  The old, mature universes are vastly outnumbered by universes that have just barely begun to evolve. Guth called it the "Youngness Paradox."

Guth says that "the synchronous gauge probability distribution strongly implies that there is no civilization in the visible Universe more advanced than us. We would conclude, therefore, that it is extraordinarily improbable that there is a civilization in our pocket Universe that is at least one second more advanced than we are. Perhaps this argument explains why SETI has not found any signals from alien civilizations.”

I'm not sure what it means for the number of civilisations that might be one second behind us.   But if it  means there may be many of them around at the moment, and if within the next (say) 300 years that a significant proportion of them start to explore the stars, what does the maths suggest as to how long it may take before we are likely to bump into one?    A lot depends on whether faster than light travel is possible, I guess.