"I do. How else can you explain the very fact which you have just quoted, that no evidence of the presence on these invisible entities has previously been recorded?"
"Where did they come from?"
"They may have come from anywhere in the solar system, or even from outside it but I fancy, that they are from Mars or Venus."
"Why so?"
"Because they are the two planets nearest to the earth and are the ones where conditions are the most like they are on the earth. Venus, for example, has an atmosphere and a gravity about .83 of earthly gravity, and life of a sort similar to that of the earth might well live there. Further, it seems more probable that the invaders have come from one of the nearby planets than from the realms of space beyond the solar system."
"What about the moon?"
"We can dismiss that because of the lack of an atmosphere."
"It sounds logical, Jim, but the idea of living organisms of sufficient size to lift a child into the air who are invisible seems a little absurd."
"I never said they were invisible. I don't think they are."
"But they must be, else why weren't they seen?"