Shouldn't it read
"FTL is impossible" is undesirable if and only if FTL is possible."
as it stands it reads "FTL is impossible" is undesirable if and only if and only if (iff) FTL is possible.
Actually, it should be "FTL is impossible" is undesirable if and only if FTL is possible."
Another monthly installment of the rationality quotes thread. The usual rules apply: