Of course “never” is testable. The way to falsify is to exhibit a counterexample. “Human beings will never design a heavier than air flying machine” (Lord Kelvin, 1895), “a computer will never beat the human world champion in chess,” etc. All falsified, therefore, all testable. If anything, an infinite horizon statement like “never” is more vulnerable to falsification, and therefore should get more “scientific respect.”
It’s only testable in one direction—if you like, “never” is testable but “ever” isn’t. I don’t have a formal argument to hand, but it seems vaguely to me that a hypothesis preferably-ought to be falsifiable both ways.
Of course “never” is testable. The way to falsify is to exhibit a counterexample. “Human beings will never design a heavier than air flying machine” (Lord Kelvin, 1895), “a computer will never beat the human world champion in chess,” etc. All falsified, therefore, all testable. If anything, an infinite horizon statement like “never” is more vulnerable to falsification, and therefore should get more “scientific respect.”
It’s only testable in one direction—if you like, “never” is testable but “ever” isn’t. I don’t have a formal argument to hand, but it seems vaguely to me that a hypothesis preferably-ought to be falsifiable both ways.