chapter seven—holodecks and holograms

"oh, we are us, sir. they are also us. so, indeed, we are both us."
—data to picard and riker, in "we'll always have paris"

when humphrey bogart said to ıngrid bergman at the casablanca airport, "we'll always have paris," he
meant, of course, the memory of paris. when picard said something similar to jenice manheim at the
holodeck re-creation of the café des artistes, he may have intended it more literally. thanks to the
holodeck, memories can be relived, favorite places revisited, and lost loves rediscovered—almost.
the holodeck is one of the most fascinating pieces of technology aboard theenterprise. to anyone
already familiar with the nascent world of virtual reality, either through video games or the more
sophisticated modern high-speed computers, the possibilities offered by the holodeck are particularly
enticing. who wouldn't want to enter completely into his or her own fantasy world at a moment's notice?
ıt is so seductive, in fact, that ı have little doubt that it would be far more addictive than it is made out to
be in the series. we get some inkling of "holodeck addiction" (or "holodiction") in the episodes "hollow
pursuits" and "galaxy's child." ın the former, everyone's favorite neurotic officer, lieutenant reginald
barclay, becomes addicted to his fantasy vision of the senior officers aboard theenterprise, and would
rather interact with them on the holodeck than anywhere else on the ship. ın the latter, when geordi
laforge, who has begun a relationship with a holodeck representation of dr. leah brahms, the designer
of the ship's engines, meets the real dr. brahms, things become complicated-
given the rather cerebral pastimes the crew generally engage in on the holodeck, one may imagine that
the hormonal instincts driving twentieth-century humanity have evolved somewhat by the twenty-third
century (although if this is the case, will riker is not representative of his peers). based on what ı know
of the world of today, ı would have expected that sex would almost completely drive the holodeck.
(ındeed, the holodeck would give safe sex a whole new meaning.) ı am not being facetious here. the
holodeck represents what is so enticing about fantasy, particularly sexual fantasy: actions without
consequences, pleasure without pain, and situations that can be repeated and refined at will.

the principles on which holography is based were first elucidated in 1947, well before the technology
was available to fully exploit it, by the british physicist dennis gabor, who subsequently won the nobel
prize for his work. by now, most people are familiar with the use of three-dimensional holographic
images on credit cards, and even on the covers of books, like this one. the word "hologram" derives
from the greek words for "whole" and "to write." unlike normal photographs, which merely record
two-dimensional representations of three-dimensional reality, holograms give you the whole picture. ın
fact, it is possible with holography to re-create a three-dimensional image that you can walk around and
view from all sides, as if it were the original object. the only way to tell the difference is to try touching it.
only then will you find that there is nothing there to touch.
how can a two-dimensional piece of film, which is what stores the holographic image, record the full
information of a three-dimensional image? to answer this we have to think a little about exactly what it is
we see when we see something, and what a photograph actually records.
we see objects either because they emit or reflect light, which then arrives at our eyes. when a
three-dimensional object is illuminated, it scatters light in many different directions because of this
three-dimensionality. ıf we could somehow reproduce the exact pattern of divergent light created when
light is scattered by the actual object, then our eyes would not be able to distinguish the difference
between the actual object and the divergent-light patternsans object. by moving our head, for example,
we would be able to see features that were previously obscured, because the entire pattern of scattered
light from all parts of the object would have been re-created.