Bones of the Earth Read Online Free PDF

self tell you why. With age comes wisdom, you know.”
    Down the aisle Griffin went. He stooped to pick up the tennis ball along the way, and then disappeared through the double doors.
    His other self reached into a pocket and set that same tennis ball atop the podium. “There goes the pragmatic resolution of our dilemma. By making a simple loop in time, I was able to witness the same moment from two different perspectives. Causality was not violated. There was no paradox involved.
    â€œSimilarly, all your actions in the past—all your future actions, everything you will do—have already existed for millions of years, and are a part of what led inevitably to this present moment. Don’t obsess about the repercussions of simple actions. Step on as many butterflies as you wish—the present is safe.
    â€œHowever, suppose when I entered the room just now, I decided to behave differently than I had witnessed myself behaving the first time. Suppose that rather than shake hands, I’d decided to punch myself out. Suppose then my earlier self had become so irate that he refused to travel into the past. What then?”
    â€œIt couldn’t have happened!” somebody called from the audience. “It didn’t—so it couldn’t.”
    â€œSo common sense would tell you. However—slide!” The incomprehensible physical equations again filled the screen. “Common sense has very little to do with physics. Unhappily, paradox is only too possible.
    â€œLet’s imagine that when I came into this room, with this tennis ball in my pocket, I kicked the original of it out of my way in the aisle, sending it skittering in among this amiable sea of friendly faces. This would have prevented my earlier self from picking it up in the first place. Where, then, would this tennis ball have come from? Suppose also that I subsequently took this ball and gave it to my earlier self to take back in time so I could bring it here to pass back into time.” He tossed the ball back and forth between his hands. “Where did it come from? Where does it go? If it came spontaneously into being, as a miracle of quantum physics, then why does it have the Spalding logo stamped into its side?”
    Nobody laughed. A few in the audience cleared their throats uncomfortably.
    â€œEither of those instances—the refusal to perform a previously witnessed act, or the tennis ball from nowhere—would have been a massive violation of cause and effect. There are extremely good reasons why this cannot be allowed to occur. I am not permitted even to hint at these reasons, but I can assure you that we take them very seriously indeed.
    â€œThe bottom line is simply this: Could you go back in time and kill your own grandfather? Yes and no. Yes, it could happen. There’s nothing in the physical nature of reality to prevent it. No, we won’t permit it to happen.
    â€œWe have means of detecting a paradox before it actually happens—and, again, I won’t tell you what they are. But any threat to this precious and fragile enterprise will be nipped in the bud, I can assure you that. And those responsible will be punished. No exceptions. And no clemency, either.”
    He slipped the tennis ball back in his pocket. “Any questions?”
    A spry old gent who might have been the father of someone Leyster once worked with, stood. “What if, in spite of your best efforts, a paradox slips by you?”
    â€œThe entire project would be canceled. Retroactively. By which I mean that this wonderful opportunity will then have never been placed before you. It’s harsh, but—I have been assured by those who know—absolutely necessary.”
    A woman stood. “What would become of us, then?”
    â€œCut free from causality, our entire history from that moment onward would become a timelike loop and dissolve.”
    â€œExcuse me. What does that mean?”
    Griffin smiled.