I think the same thing as I did about the Kon-tiki, or that French guy who rowed a rowboat all the way across the Atlantic Ocean.
They each proved that it could be done.
Which isn't the same thing as proving anybody actually did it.
More persuasive to me are the arguments about much lower sea levels, due to the ice age, and also continental drift. The Pacific Ocean gets narrower, and the Atlantic ocean gets wider, by about 3 feet per year.
We're talking 600,000 years ago. 500,000 years, times 3 feet, is...1,500,000 feet...which is, what? about 300 miles? That's a lot of movement. Stuff may not have been in the same place since way back then.
I don't doubt that men crossed some passages, because it made sense, and they could see the other side.
Other crossings may have been "sweepstakes routes" not really traversed intentionally, but crossed due to freak accidents and luck, like folks getting blown out to sea by a hurricane, clinging to junk, and washing ashore somewhere. It happens today, and probably happened then. But today we send a helicopter to pick 'em back up.
That's right. The Australian plate is moving north into the Asiatic plate. The meeting point is creating the Indonesia archipelago with all its incumbent volcanoes (Krakatoa, for example) and earthquake zones. Australia started out far to the south, attached to Antarctica, as did India, which when it "hit" Asia, created the Himalayas. Also, Africa is moving north. One day the Mediterranean sea will be a Himalayan size mountain range.
More like three inches, which gets you about 24 miles over 500,000 years (if my math's right)
I don't see why they would have had to see the other side to set out to cross oceans. People do stuff like that all the time. After all... the only difference between madness and genius is results.