To insist, as philosophers have done for centuries, that knowledge requires some kind of “timeless certainty” is not a search for certainty – it’s a refusal to be certain. It makes knowledge an impossible ideal -- “the perfect being the enemy of the good.”
It is a way of always knowing less than you do know, and ensuring that you never know anything for sure. To make yourself uncertain by means of the certain; what could be more ironic?
But as Tibor Machan discusses, Ayn Rand made what amounts to a unique achievement. She validated common sense. “What Ayn Rand proposed is that human beings, if they do the hard work, can obtain knowledge just fine and dandy. And there is, of course, ample evidence of this in the sciences, in technology and—let’s not forget—ordinary life. But what is this human knowledge?
As the name of her system makes evident, the key to knowledge is objectivity. As Rand herself puts the point in her book, Introduction to Objectivist Epistemology”:
“Objective validity is determined by reference to the facts of reality. But it is man who has to identify the facts; objectivity requires discovery by man—and cannot precede man's knowledge, i.e., cannot require omniscience. Man cannot know more than he has discovered—and he may not know less than the evidence indicates, if his concepts and definitions are to be objectively valid.”
To know. Not just to trust, but to know – to know down to the root, which you need to if you’re about to bet your life on it. That’s what astronauts do – or adventurers—or new people taking new paths down new roads---or a woman riding seven-thousand tons of steel and freight thundering along at over one-hundred miles per hour like "a great silver bullet" through great cities and along narrow mountain trails – a train held above the precipice by just two strips of green-blue metal strung in a curve along a narrow rock shelf, strips of metal no wider than a woman's arm. . . People, that is, like Dagny Taggart.