Can we ascertain the falsity of a given scientific hypothesis H? Alternatively, could we ascertain the truth of H? One tradition answers these questions asymmetrically as follows: Alas, unfavorable results furnished by just one kind of experiment suffice to guarantee the falsity of an otherwise highly successful hypothesis. And would that favorable experimental findings had a comparable capability of establishing the truth of a hypothesis! Thus, the scientist is held to be laboring under a discouraging handicap in his quest to glean nature's secrets. His most triumphant theories are never safe from refutation by potential contrary evidence. Hence, none of his hypotheses can ever be known to be true with certainty. But if even a small amount of contrary evidence does materialize, then the most celebrated of hypotheses is indeed known to be false.