[Old Professer]

Today, we know the islands are there; why would a stone-age man assume that land masses were scattered all about the sea if he could not see them or be able to talk to someone who had seen them?

Am I to assume that a pre-historic Gilligan got lost on a summer's day?

[blam]

A day fisherman was blown to the island and managed to make it back to his village?

[RightWhale]

why would a stone-age man assume that land masses were scattered all about the sea

There are signs of land long before land comes into view. If the next island were 30 miles, they would be 100% sure. To cross to Easter Island would take navigational skills using stars, and a spirit of adventure.

[Andonius_99]

No, H. Erection-us just kicked erectors (they're not people yet, so we'll call 'em that) out that they didn't like, put them in a boat, and let them float away...kind of a "prehistoric dumping junk into space" routine...