There is a legend in ancient Greek mythology about the Ship of Theseus, a godly ship kept in a harbor as a monument. When its timbers decayed, they were replaced with new ones, which were precise duplicates of the previous ones. It was such a routine maintenance job that it presented a philosophical conundrum that had stood the test of time for millennia: if every single component of the ship is eventually replaced, is it still the same Ship of Theseus? Consider, now, what it would be like to gather all the soggy, rejected planks and reconstruct them into a second ship. Which one of the two—the perpetually preserved vessel or the reconstructed relic—is the actual article? This paradox, initially a philosophical conundrum in material objects and identity, has discovered a potent new habitat in our cyberspace lifestyle, in which it compels us to rethink our very notion of self, property, and reality. At the crux of the paradox is the issue of identity through time.
What constitutes an object, the thing itself? Is it its original substance, its single configuration, its use, or its uninterrupted chain? The world of substance is durable, to a point; a piece of wood will have some longevity, though ultimately it will rot. But the world of the digital is not. It is a world of pristine information, of bits and bytes that are inherently fluid, transient, and duplicable. Here, the Ship of Theseus isn't just a philosophical exercise; it is the operating principle behind all that functions, and its stakes are vast and startling. Think about the applications you use daily.
An operating system, such as Windows, or software, such as Microsoft Word, is constantly changing. With each patch, security update, or feature update, small bits of the original code are deleted and rewritten. With five years and hundreds of updates, there is possibly not a line of the original code that you first installed. Is it still the same program? We would say so because its name and purpose have continued in a stream. But the paradox requests that we consider challenging this assumption. The software's "identity" appears not to be linked to its physical form (there is none), but to its name, its purpose, and its constant string of upgrades. It is the Ship of Theseus, floating across a sea of constant, unseen renewal. It only becomes more complicated when we consider our own data and digital identity.
The human form has its own Ship of Theseus paradox, as it has its cells replaced. But our digital self—the photographs, posts, emails, and interests that make us up online—is evolving as well. We change our profile photos, covering up the previous ones. We revise our posts. We update our listed activities and employers. In a decade, every piece of information that originally formed your social networking profile can be altered or erased. Is the profile today the same "you" who was established ten years ago? Its function—to be you—has not changed, but its whole content has. We intuitively know it is the same profile due to its continuous history, yet our digital legacy from our past self does not, and has been replaced piecemeal by new information. The paradox comes to its most frustrating expression with the idea of the replica and the backup.
In the ancient myth, the rebuilt boat using the original timbers is a rival claimant to the title of "true ship." In cyberspace, it is not a dream; it is standard procedure. When you replicate your computer, you make an exact, bit-by-bit replica of your files—a digital replica of your Ship of Theseus at some particular moment. If your source machine is burned to ashes in a fire and you reload everything from the backup onto a brand new machine, is it your computer? The vast majority would sense that it is. Their files, their configuration, and their online life have been reloaded. The identity has been duplicated, the same way a soul is duplicated in reincarnation tales. The machinery may be new, but the line of information is preserved. But picture every boat being able to sail.
Picture a high-tech teleportation machine that scans you, kills you, and teleports back a replica to Mars. The fellow on Mars has your memories and thinks he is you. But is he? This is the Ship of Theseus paradox in insurance form and has the terrifying potential of whether our identity is inextricably linked to a particular bodily form or to the pattern of information that we possess. If you could make a perfect simulation of your mind on a computer, would you be it, or merely a good simulation? Virtual age compels this science fiction question to philosophical mandates as we start wrestling with things such as mind uploading and digital immortality. And, too, the paradox dissolves the concept of ownership in the digital world.
When you "purchase" a digital film or an e-book, you do not own something. You have the right to access some set of data. The firm that sold it to you can, and does, modify that document. They may trim content for purposes of licensing, rephrase it for contemporary sensibilities, or trim the layout. The electronic appliance you "possess" today is not the same as the one you bought yesterday. Its planks have been swapped out. Do you still possess the same? The philosophy and jurisprudence for so doing are tenuous, observing that our traditional intuitions about property, built around long-term physical objects, disintegrate in an information world. So what's left for us?
The digital world does not reduce the Ship of Theseus paradox; it amplifies it and brings it into our daily lives. It means that in a world of information, identity is not in the content, but in the pattern, form, and continuing story. The new software is the "true" software because its history is intact. The rebuilt backup is "your" computer because the structure of the information was retained and rebuilt. This is a functionalist conception of identity: the thing is determined by what it is for and what its history is, not by what it is constituted of. Nevertheless, the rebuilt ship—the clone, the duplicate—gives us pause.
It breaks a profound human instinct that there is something unique about the first case, that very specific, historical sequence of cause and effect, which can never be exactly replicated. The virtual world, with its exact replicas and pitiless updates, puts this instinct in question at every turn. It makes us confront what we most prize: material content, informational form, or ongoing record of transformation. The more of our life that we live in virtual worlds, accumulating virtual property and even virtual lives, the Ship of Theseus's old conundrum is not a philosophical thought experiment anymore, but a necessary traveling companion on the path through the dizzying map of identity, continuity, and soul in a world where anything can be replicated, replaced, and reconstituted by the press of a button.