Loeb’s theorem shows that if PA proves “not P(C)->C”, then PA proves C (using P(X) for “X is provable in PA”).
It follows from that, using the Deduction Theorem, that PA proves “(not P(C)->C)->C”; it does not follow that “(not P(C)->C)->C” is a logical tautology.
From that, you obtain, similarly, that PA proves “(not P(C)) → C”. And you say “I cannot prove that 2 = 1″. Sure, you cannot, but can PA? That’s the real question.
There’s nothing particularly surprising about PA proving “(not P(C))->C”. After all, were PA to prove “not P(C)” for any C, it would prove its own consistency, and therefore be inconsistent, and therefore prove C.
Stanislaw Lem treated the theme of ungraspable aliens with some success; “Solaris” is better-known, but “Eden” is even more striking in its exploration of the failure to understand.
The remark about the “Star Trek” episode seems strangely inept; surely the writers weren’t concerned about the plausibility of the identical parallel evolution—it was just a literary device for them. Criticizing that as a failure to imagine divergent evolution is a bit like criticizing a soap opera for using the twin device to keep an actor after the character dies; after all, the writers could have refrained from doing that, and instead put in a new different character with a different actor...