In the television series Star Trek the crew of the spaceship Enterprise take their vacations on something called the “Holodeck”—a play on the words “holiday” and “holovision.” They are transported into a virtual world in every way as real-seeming as the one they live in on the Enterprise. Plus, that world can be anywhere and at any point in history, or pre-history for that matter. They can go back to the gun-slinging days of the American frontier or the time of the dinosaurs a hundred million years earlier. But whatever place and period they choose to visit, they exist there as real people vulnerable to the bullet of a six-shooter or the jaws of a tyranosaurus.
I don’t remember any members of the Enterprise explaining just how a Holodeck worked. Presumably, the virtual reality was generated algorithmically in the same way a virtual reality is produced for us today by putting on special goggles hooked up to a computer. Only, in Star Trek the “reality” is of a much more sophisticated kind. Science fiction is more about the present, in any case, than it is about the future, a matter of what-if added to what-is. Star Trek was entertainment, not epistemology. The play’s the thing, not its plausibility. The audience must believe, at least for as long as the show lasts, that the characters have been transported in space and time and exist there in as real a state as if they were still back on board the Enterprise. That’s no more a demand on an audience than to expect them to believe a spaceship can travel at “warp speed,” a catchy phrase for a phenomenon best not discussed in detail.
But that holodeck, a reality generated by machine, can be taken as a metaphor for the reality we earthbound folk actually live in, except our reality, the only one there is, is generated not by computers but by our imaginations, continuously, for as long as the organs we need to create that unimaginable imaginary are in good working order. But it is not just a reality we generate, it and we are that reality, the only reality there is….