when Christopher Columbus
sailed to Hispanola, the natives could not see their huge ships. The
movie claims that the brain can not "see" things it's not familiar with,
and not ready to see. The natives only saw the ships after a Shaman who
was able to see them, told the others they were out there

"I think," said Ford in a tone of voice that Arthur by now recognized as one that presaged something utterly unintelligible, "that there's an SEP. over there." 

He pointed. Curiously enough, the direction he pointed in was not the one in which he was looking. Arthur looked in the one direction, which was toward the sight screens, and in the other, which was at the field of play. He nodded, he shrugged. He shrugged again. 

"A what?" he said.

"An S.E.P" 

"An S… ?" 

"…E.P."

"And what's that?" 

"Somebody Else's Problem," said Ford. 

"Ah, good," said Arthur, and relaxed. He had no idea what all that was about, but at least it seemed to be over. It wasn't. 

"Over there," said Ford, again pointing at the sight screens and looking at the pitch. 

"Where?" said Arthur. 

"There!" said Ford. 

"I see," said Arthur, who didn't. 

"You do?" said Ford. 

"What?" said Arthur 

"Can you see," said Ford patiently, "the S.E.P.?" 

"I thought you said that was someone else's problem." 

"That's right." 

Arthur nodded slowly, carefully and with an air of immense stupidity.

"And I want to know," said Ford, "if you can see it." 

"You do?" 

"Yes!" 

"What," said Arthur, "does it look like?" 

"Well, how should I know, you fool," shouted Ford. "If you can see it, you tell me."

Arthur experienced that dull throbbing sensation just behind the temples that was a hallmark of so many of his conversations with Ford. His brain lurked like a frightened puppy in its kennel. Ford took him by the arm.

"An S.E.P.," he said, "is something that we can't see, or don't see, or our brain doesn't let us see, because we think that it's somebody else's problem. That's what S.E.P. means. Somebody Else's Problem. The brain just edits it out; it's like a blind spot. If you look at it directly you won't see it unless you know precisely what it is. Your only hope is to catch it by surprise out of the corner of your eye."

"Ah," said Arthur, "then that's why..

"Yes," said Ford, who knew what Arthur was going to say.

"…you've been jumping up and…"

"Yes."

"...down, and blinking…"

"Yes."

"and..."

"I think you've got the message."

"I can see it," said Arthur, "it's a spaceship."