Twins Prime


I don’t believe in having body doubles. — Nicole Mary Kidman, AC[1]


In the theatre section of my bookcase rest two copies of The Complete Works of William Shakespeare, side by side. Each contains the same 38 plays by the same author, which is why we can call them two copies of the same book. In a sense these books are twins, and from the description so far they are identical.

Still, these twins are not identical in the least. One is a heavy Oxford edition, pristine in its original slipcover; the other is an early 20th-century edition bound in crumbling blue leather. The pages of the former are crisp and white where those of the latter are yellowed and threadbare (with foxing around the edges). Content-wise, their chosen orderings of the plays differ, as do their introductions, spellings, and even their selected sources for the texts themselves. While on some Platonic formal plane they may be identical, there are uncountably many details that render them distinct, distinguishable entities: individuals.

Distinct identity is blurry for information objects. A piece of digital data can be copied exactly, down to the bit; the only distinction possible to make between the copies is the location within the file system (and then, via the file system, metadata such as modification date). If two copies of an e-book edition of old Billy’s Complete Works were to switch places while our backs were turned, we would have no way of knowing. Any notion of intrinsic, metaphysical identity evaporates in the realm of information.

Which brings us to macroscopic teleportation. As opposed to traditional (or as certain folks would term them “real life”) transportation methods, which involve continuous displacement achievable through purely physical means, teleportation (in most forms) involves the treatment of the passenger as information. The arrangement of particles in the passenger’s body is analyzed and transmitted to the destination, where the data is used to reconstruct the body.

Generally, the original body is destroyed in the process, which is a handy plot device for sidestepping metaphysical questions, protecting traditionalist sensibilities, and encroaching on Shane Carruth’s territory. Countless science fiction writers (including my teenage self) have asked the following question: “Does teleportation actually move a person, or does it just kill them and make a copy of the deceased?” The distinction feels important, particularly to those readers who hope to teleport themselves one day. The key concern seems to be that the individual survive the process with their identity unscathed.

In grappling with the interface between science and philosophy, I often recall Bertrand Russell’s famous remark[2]: “Every philosophical problem, when it is subjected to the necessary analysis and justification, is found either to be not really philosophical at all, or else to be, in the sense in which we are using the word, logical.” In this context, that means ‘define your terms!’ What do we mean by “person,” “kill,” or “copy”?

Given an information theoretic notion of copying (duplication of each element), the question of whether or not such a process is “killing” comes down to the definition of “person.” If the person is killed by teleportation, then the person stepping out the other end cannot be the person who stepped in. But they’re identical, right down to the chirality of each fermion. This points to some extraphysical property from which identity is derived—a “soul” or (more metaphysically neutrally) a ghost in the shell.[3]

Without that ghost, the shell is the person, and every detail of identity and personality are data—able to be copied without loss of identity, or to be duplicated without differentiability. In that case, the “original” who steps into the teleportation booth (or teleportation pod or teleportation leotard or whatever) and the “copy” who step out of the destination’s leotard have equal claim to that identity. “Identity” as a property of uniqueness falls apart without a ghost in the shell, and becomes instead a sort of biological algorithm, physically encoded in our brain and central nervous system.

Beside the immediate implications of duplication (for a low low price, YOUR company can have 1000 copies of its most productive employee!), this brings up lots of fun potential for the treatment of that identity-data as data. Mind-swapping, brain backups, and such are relatively straightforward to imagine (particularly with such procedures as the firmware-style “active architecture” used in the sci-fi television series Dollhouse).

One way or the other, the ability to fully model the workings of a human brain is not far off. Initiatives such as the Blue Brain Project are making bold strides toward synthetic brain systems. If we keep the greenhouse effect at bay, the ability to duplicate a person is likely to develop at some point in our future.

This will not be the first time that the advancement of technology settles what has previously been a metaphysical or ideological debate into a concrete feature of our shared reality, but it will be on of the first times that this process applies to such a fundamental, ageless question as “who am I?”



{C}[1]{C} Interview, “Nicole Kidman, in control of her career and love life”, USA Today, 24 Dec 2003

{C}[2]{C} Russell, Bertrand, Our Knowledge of the External World (1914), p. 33

{C}[3]{C} After the excellent seinen manga series by 士郎 正宗 Masamune Shirow.