For years scientists have been scanning the skies in the hope of finding life on other planets. But in spite of the ever-increasing sophistication of the equipment they employ, some of it costing hundreds of millions of dollars, not the first shred of evidence of such life has been forthcoming. And there is no reason to think that these scientists will be anymore successful in the future, no matter how much money is invested in the search. The dream of finding extraterrestrial life is destined to remain a dream, as science' s experience up to this point should indicate. Which one of the following most accurately states the main point of the argument? ['Only if scientists had already found evidence of life on other planets would continued search be justified.', 'Scientists searching for extraterrestrial life will not find it.', 'There is no reason to believe that life exists on other planets.', 'The equipment that scientists employ is not as sophisticated as it should be.']