Seite 6: Questioning Reality

Like organisms evolved in gentle tide pools, who migrate to freezing oceans or steaming jungles by developing metabolisms, mechanisms and behaviors workable in those harsher and vaster environments, our descendants may develop means to venture far from the comfortable realms we consider reality, into arbitrarily strange volumes of the all-possible library. Their techniques will be as meaningless to us as bicycles are to fish, but perhaps we can stretch our common-sense hobbled imaginations enough to peer a short distance into this odd territory.

Physical quantities like the speed of light, the attraction of electric charges and the strength of gravity are, for us, the unchanging foundation on which everything is built. But if we are the products of self-interpretation, this stability may simply reflect the delicacy of our own construction - our biochemistry would malfunction if physical constants varied, and we would cease to be. For the same reason, the rules must have held steady over a long period, so evolution could accumulate our many intricate, interlocking internal mechanisms.

Our engineered descendants may be more flexible. Perhaps mind-hosting bodies are possible that are adjustable for small changes in, say, the constant of electric attraction. An individual who tuned its body for a slightly increased constant should then find itself in a physical universe appropriately altered. It would be a one-way trip. Acquaintances in old-style bodies would be seen to die - among fireworks everywhere, as formerly stable atoms and compounds disintegrated. Turning the tuning knob back would not restore the lost continuity of life and substance. Back in the old universe everything would be normal, only the acquaintances would witness an odd suicide by tuning knob. Such irreversible partings occur elsewhere in physics. The many-worlds interpretation calls for them, subtly, at every recorded observation. General relativity offers dramatic event horizons: an observer falling into a black hole sees a previously inaccessible universe ahead at the instant she permanently loses the ability to signal friends left outside.

Visiting offbeat worlds, where the dependable predictability of the common-sense no longer holds, is probably much too tricky for crude techniques like the last paragraph's. It must be far more likely that mechanical fluctuations or other effects persistently frustrate attempts to retune a body than for physical constants to actually change. Yet once our descendants achieve fine-grain mastery of extensive regions of the universe, they may be able to orchestrate the delicate adjustments needed to navigate deliberately among the possibilities, perhaps into difficult but potent regions shaped by interrelationships richer than those of matter, space and time. Time travel, a technology well beyond our reach but faintly visible on the horizon, may hint at a few of the issues.