A Metaverse definition using Grounded Theory


  • In 2003, Second Life was one of the first virtual worlds to be called a "metaverse", fulfilling the books description;
  • I argue that interoperability "is the determining factor for individuals as to how close we are to obtaining the Metaverse";
  • The majority (at least 13 of 20 responders) provide a definition of the Metaverse that is encompassed by the existing scientific definition;
  • No need (yet) to advance the currently accepted scientific definition, in order to combine the Metaverse with other technologies
  • And yes, the Metaverse might be the behind the scenes resource, for spatial computing, for all in the future.

The definition for the Metaverse has been a topic of discussion lately. Many people have provided a Metaverse definition, but few have been able to explain the relationship of all the tech terms with the greater Metaverse. In order to shed some light on how these definitions relate and perhaps why they are relative, this article will distill the Metaverse definitions using Grounded Theory. As an exploratory piece, Cathy Hackl (2021) surveyed professionals and provides 20 different definitions for the Metaverse. In her article, she asks if the currently accepted Wikipedia definitions, which are based on scientific publications, "really reflect what many in the technology and business world refer to when they use the word metaverse?" (Hackl 2021)

Before we can discuss what the Metaverse is, we must first know what a virtual world is.

Virtual World defined

To be able define "Virtual World" from a technical perspective, I used grounded theory (Johannesson and Perjons 2014) allowing words/concepts to be added to a candidate definition; if an added word/concept did not advance the candidate definition, the word/concept was superfluous. The technical definition by myself (Nevelsteen 2018) states a virtual world to be:

"A simulated environment where MANY agents can virtually interact with each other, act and react to things, phenomena and the environment; agents can be ZERO or MANY human(s), each represented by MANY entities called a virtual self (an avatar), or MANY software agents; all action/reaction/interaction must happen in a real-time shared spatiotemporal nonpausable virtual environment; the environment may consist of many data spaces, but the collection of data spaces should constitute a shared data space, ONE persistent shard."

Bartle provides another iteration of his definition of "Virtual World" in his book MMOs from the Inside Out. Bartle’s (2015) definition states "a virtual world is something with the following characteristics:

  • It operates using an underlying automated rule set-its physics.
  • Each player represents an individual "in" the virtual world-that player’s character.
  • Interaction with the world takes place in real time-if you do something, it happens pretty much when you do it.
  • The world is shared-other people can play in the same world at the same time as you.
  • The world is persistent-it’s still there when you’re not.
  • It’s not the real world."

The two definitions are essentially equal.

The Metaverse described by Snow Crash

As an exercise, let us apply Grounded Theory towards a Metaverse definition.

In the book Snow Crash (Stephenson 1992), the protagonist Hiro enters the Metaverse, which has physics and allows people to react in real-time in the shared virtual space, "people are pieces of software called avatars", and the Metaverse continues to exist when Hiro exits to "Reality" (i.e., the physical world). At this point we can start our grounded theory equating the Metaverse to a virtual world. If the words/concepts added to the definition don’t advance the definition, we can safely drop the added word/concept.

The professionals surveyed by Hackl (2021) characterized the Metaverse to be: persistent, live digital, have a sense of agency, social presence, and shared spatial awareness (Piers Kicks); a sensory leap as ‘place’, motion and presence, support our belief in that shared illusion as a space, be more closely aligned with stereoscopic perception (Kenneth Mayfield); a digital space, enabling humanity to experience the things that make us human, provide hyper social co-experiences, allow people to connect in authentic ways (Samuel Jordan); support non-fungible and infinite items and personas, be not bound by conventional physics and limitations (Luke Shabro); have voice interaction (Neil Redding); be interactive and real-time rendered (Rafael Brown). Hackl herself adds (Bhaduri 2021) that the Metaverse should allow people to "share virtual experiences" and should include Cloud Computing technologies. All these characteristics are superfluous, because these characteristics are captured by the concept "virtual world". Piers Kicks adds the Metaverse should enable the "the ability to participate in an extensive virtual economy with profound societal impact"; the economy of some virtual worlds already surpasses that of some nations (Diaz 2018). Luke Shabro’s "non-fungible and infinite items and personas" have existed in virtual worlds, just not across many virtual worlds. Neil Redding adds that there should be "effectively infinite space"; one can imagine that they mean the Metaverse to be truly expansive, but the criteria is satisfied by the virtual world in Minecraft. JB Grasset provides the criteria of "a social network based on gaming", but both "social worlds" and "game-like worlds" (Bartle 2015) exist as virtual worlds and the social networks inside those worlds are no less technically expansive then, for example, Facebook. Samuel Jordan adds people should be able to "create memories that rival physical experiences", but this is already the case for virtual worlds as observed by Pearce and Artemesia (2009). Lucas Rizotto specifies the Metaverse should be "a mass delusion", to which MMOs cater, a subset of virtual worlds.

It could be argued that virtual worlds on flat desktop or mobile screen do not provide the "hyper social" experiences and the "stereoscopic perception" specified above. To remedy this, we add Virtual Reality (VR) to the candidate Metaverse definition. Hiro enters the Metaverse through his goggles and earphones, a head-mounted display providing a VR interface to the Metaverse. Hackl and Kenneth Mayfield mention VR specifically, with others mentioning VR, in combination with Augmented Reality (AR) or in the superset XR. Our candidate definition is then: a virtual world with VR.

We have not completely satisfied the vision of the Metaverse described in Snow Crash. Initial virtual worlds were run on a single centralized server by one organization, but the book describes the Metaverse as "the graphic representation ... of a myriad different pieces of software that have been engineered by major corporations ... the money these corporations pay ... pays for developing and expanding the machinery enabling the [Metaverse] to exist" (Stephenson 1992). Second Life by Linden Labs set out to build the Metaverse in 2003; they allowed anyone to buy land/servers that would link into their virtual world. The owners of land could build whatever they desired and the Second Life platform provided the tools for content generation, including the scripting of behaviors. Second Life earned the title of "metaverse" by some, but is still only a virtual world with "no interworld transit capabilities" (Dionisio, Burns III, and Gilbert 2013). VR technology was not in the hands of many consumers, so Second Life could not entirely provide the interaction with the Metaverse described in the book. To my recollection, the book doesn’t specify any more technological aspects that would disqualify Second Life. I don’t recall if Snow Crash mentions "spatial audio" or "tactile feedback" as Neil Redding mentions (Hackl 2021). At this point it is no longer the book, but modern technological advances that are pushing the candidate definition.

A myriad pieces of software

The "myriad different pieces of software" above can be interpreted differently. Someone wanting to architect the Metaverse could try and provide a common platform which everyone would adopt, allowing various "major corporations" to setup their own virtual world and add it to the would-be Metaverse. This is what Dionisio, Burns III, and Gilbert (2013) describes as a MetaGalaxy, "multiple virtual worlds clustered together as perceived collectives under a single authority"; the someone creating the Metaverse platform being that authority. This is the dystopian future Stephenson described in Snow Crash, i.e., major corporations had "to get approval from the Global Multimedia Protocol Group". At this point, we can expand the candidate Metaverse definition to be: a MetaGalaxy with VR.

Without providing a reference, I think it is safe to say that the number of virtual worlds exploded in the last decade and we have many MetaGalaxies (subverses of the Metaverse today). The reason, the current status of the Metaverse isn’t the dystopian future described in the book is because there are already many of these virtual worlds and MetaGalaxies/subverses to choose from today. People are also calling for an "open" Metaverse in order to explicitly avoid a single authority. In Snow Crash, the Metaverse was "made available to the public over the world-wide fiber-optics network"; this would be the Internet. To avoid a single regulating organization, the candidate Metaverse definition can be specified as: a collection of many virtual worlds and MetaGalaxies/subverses with VR, linked together through the Internet. Returning to the various Metaverse definitions provided by Hackl (2021), the Metaverse is further characterized as: decentralized (Ryan Gill); a universe (Piers Kicks); where people can create their own world (Tom Allen); millions of digital galaxies (Claire Kimber); and, the next iteration of the Internet (Elena Piech). Hackl (Bhaduri 2021) corroborates the latter characteristic as "the future of Internet". Given the current candidate Metaverse, these characteristics are incorporated. Tom Allen further adds that the Metaverse should be an "exponentially growing virtual universe"; I don’t think the Internet has exponential growth and the Metaverse might achieve exponential growth initially, but doubtfully be sustained. Bosco Bellinghausen states the Metaverse should be "a true technological democracy"; I do not think the modern Internet can be considered a democracy and although there might be democracy technologies in the works, it is still each nation that determines the democracy for its people or not.

In my publication (Nevelsteen 2018), I argue that "Because the Internet is already mixed reality ... the Metaverse will be necessarily mixed as well". By including Mixed Reality (MR), the candidate definition becomes: a collection of many virtual worlds and subverses in XR, linked together through the Internet; with XR being the super set of VR/AR/MR. XR is mentioned several times, as a characteristic for the Metaverse, by the professionals (Hackl 2021) as: accessing the real in the digital and vice versa (Kenneth Mayfield); for the good of the real and virtual world (Esther O’Callaghan OBE); crossing the physical/digital divide between actual and virtual realities (Eric Redmond); a digitally mixed reality (Luke Shabro); the gradual convergence of the digital world with the physical world (Elena Piech); gateway between the real and the virtual reality (Bosco Bellinghausen); and, closer to reality (Ryan Gill). Richard Ward states that XR "is just in the development stages" for a would-be Metaverse. Tom Allen specifies "adapting experiences and knowledge from the physical world"; if a Mirror World is meant, this is handled below, otherwise the criteria is satisfied. Neil Redding requires "location-independent presence"; it is not entirely clear what is meant by this, but current candidate definition certainly allows a user to be in multiple places at once, but being independent of physical location will be difficult. Kenneth Mayfield says the Metaverse will be "a reconfiguring of our assumptions regarding sensory input, definitions of space, and points of access to information"; sight, sound and touch are definitely being reconfigured, but taste and smell are still research topics. Neil Redding similarly mentions, "everything we do in physical space but in a multisensory stimulation". Claire Kimber states the Metaverse is where "all digital experience sits". Hackl specifies the Metaverse will connect people, places and things, which virtual worlds already do, but with the addition of XR it is possible to connect the physical with the virtual i.e., the "convergence of physical and digital" (Bhaduri 2021).

We are HERE.

Michael Robbins considers that the word Metaverse "literally says that in the future we will live in separate universes" (Hackl 2021); I would argue that Michael Robbins’ Metaverse is here today. The candidate definition describes well the current status of the Metaverse today; little to no interoperability and limited ubiquity. I would argue that the desired level of interoperability (technical interoperability also caters to ubiquity) is the determining factor for individuals as to how close we are to obtaining the Metaverse. Richard Ward and Kenneth Mayfield consider the Metaverse to already exist (Hackl 2021). Surprisingly, no one mentioned ubiquity as an attribute of the Metaverse i.e., access via desktop, phone, head-mounted display, or other low powered devices. To incorporate ubiquity, requires tweaking the definition to: a collection of many virtual worlds and subverses, intersecting with XR, linked together through the Internet. Not all access to the Metaverse will be the same. Before mobile phones gained sufficient power to run MMO clients, World of Warcraft created a Mobile Armory app which tied low-powered mobile flat screen experiences to the immersive virtual world e.g., with chat, character profiles, monster and item lists.

Lucas Rizotto states that the Metaverse should "look like Ready Player One" (Hackl 2021); this means that just linking virtual worlds and subverses together is not sufficient. There needs to be some level of interoperability to link virtual spaces into a single perceived virtual universe e.g., in the movie Parzival could move seamlessly between the worlds of Minecraft and Doom, as demonstrated via the portal between the main universe and The Race. When a web server is setup on the World Wide Web, the server is immediate readable and links can be created to and from the web server, "teleporting" the user to another web server. Teleporting between virtual worlds today mostly involves installing specialized client software that is walled-off from other virtual worlds. In this regard, the Metaverse has not be attained. Having interoperability with respect to social networking would answer Karinna Nobbs’s (Hackl 2021) criteria for the Metaverse to be "the anchor of community life and where you meet with old and new friends", with a capability reaching beyond what Facebook currently supports. Blockchain promises various aspects of interoperability, but the existence of multiple Blockchains runs the risk of having fragmentation; there is also no guarantee that world/subverse owners will want to support Blockchain-based technology at all.

The Metaverse in Science

There are actually widely cited definitions of the Metaverse in science. In 2012, the IEEE Virtual World Standard Working Group had the following entry in their glossary.

"Multiple MetaGalaxy & Metaworld systems linked into a perceived virtual universe, although not existing purely by a central server or authority. Originally coined by Neil Stephenson in the book Snow Crash as a single Metaworld known as "The Street", the Metaverse today describes a collection of Metaworlds that are seamless and interconnected but largely decentralized which comprise the perceived virtual universe (metadata universe, metaverse) but follows closer to the overall persistence of a Metaverse from the roots of Cyberpunk genre in which systems much like the Metaverse existed but within the scope of many worlds and uses, foreshadowing a decentralized system of operation and scope. Theoretical Example: Interoperability between such systems as ActiveWorlds, SecondLife, BlueMars, and others by which a stan- dardized protocol and set of abilities exist within a common interface which can traverse among virtual world spaces seamlessly regardless of controlling entity." (P1828 2012)

A more distilled version was published in the comprehensive Metaverse publication by Dionisio, Burns III, and Gilbert (2013). And, Wikipedia editors have consolidated this into what Hackl noted as "a collection virtual shared space, created by the convergence of virtually enhanced physical reality and physically persistent virtual space, including the sum of all virtual worlds, augmented reality, and the Internet ... typically used to describe the concept of a future iteration of the internet, made up of persistent, shared, 3D virtual spaces linked into a perceived virtual universe". The candidate definition coincides to the scientific definitions of the Metaverse.

The definitions (Hackl 2021) by Claire Kimber, Eric Redmond, Esther O’Callaghan OBE, Luke Shabro, Piers Kicks, Karinna Nobbs, Tom Allen, Ryan Gill, Richard Ward, Kenneth Mayfield, Samuel Jordan, JB Grasset and Lucas Rizotto have now been reconciled. To answer Hackl’s question "But do those definitions really reflect what many in the technology and business world refer to when they use the word metaverse?" (Hackl 2021). Yes, if thirteen of Hackl’s responders would refer to the current scientific definition of the Metaverse, it would encompass their own definition.

The definition by Neil Redding highlights the shortcomings of current technology to provide a sufficiently immersive experience. We’ve seen hints of this in other definitions e.g., the one provided by Kenneth Mayfield. Dionisio, Burns III, and Gilbert (2013) name four central components to a viable Metaverse. One of those components is Realism. I argue above that interoperability "is the determining factor for individuals as to how close we are to obtaining the Metaverse"; for some realism seems to be the determining factor e.g., Neil Redding’s criteria includes: 3D photo-real immersive visuals, spatial audio and tactile feedback. Extreme examples of realism include the concepts of Digital Twins and Mirror Worlds; digital twins replicating physical world humans and mirror worlds replicating the physical world, respectively. If multiple mirror worlds exist, will there be interoperability between them? I categorized Brain-Computer Interfaces and Smart Lenses (Elena Piech) as part of the "Wearables" suggested by Hackl (Bhaduri 2021); input/output devices closest to the body to aid in achieving interaction realism. To deem realism the determining factor is entirely fine, but begs the first question: is a low-fi Metaverse allowed, before the level of realism is increased? I would argue yes, if interoperability between worlds/subverses can be achieved. Even Snow Crash describes the usage of cheap low-fi public terminals to access the Metaverse. When Dionisio, Burns III, and Gilbert (2013) refer to realism, they are referring to ‘immersive realism’, "believability rather than devotion to detail" i.e., text virtual world MUDs could satisfy that criteria. Second, we can question if the opposite is true: If there was one world/subverse that provided extreme realism, but that world/subverse was a closed system, siloed off from other worlds, would it be the Metaverse? I would argue no, since it would not constitute a universe.

Spatial Computing and beyond

Greenhalgh et al. (2001) exploited "the coextensive virtual world as a ‘behind the scenes’ resource for coordinating and managing devices and interaction in the physical space" i.e., using the ability of a virtual world for "spatial computing" (Shekhar, Feiner, and Aref 2016) in physical world. In 2012, I extended their work by successfully combining a virtual world with Internet of Things (IoT) (Nevelsteen 2016). To extend even further, it is by no means a stretch of imagination to, instead of using a virtual world, combine the interoperable Metaverse with IoT instead (Nevelsteen 2016); many virtual worlds controlling many IoT ecosystems. This coincides with the work by Rehm, Goel, and Crespi (2015) and is currently part of Cyber Physical Systems. The Metaverse would become the interconnection of, the more general, virtual environments or collections thereof, instead of virtual worlds and subverses. The ability for the Metaverse to be a behind the scenes resource for spatial computing is applicable to Robotics, Autonomous Vehicles and ultimately Smart Cities. I imagine this is what Hackl meant by "the next wave of computing" (Bhaduri 2021). Combining increased realism with the uses of spatial computing, Elena Piech’s criteria for the Metaverse to be "the next iteration of life" (Hackl 2021) can be achieved and possibly Emma-Jane MacKinnon-Lee’s "everything we have always dreamed of" (Hackl 2021).

The only criteria which remains unaddressed is that of Artificial Intelligence (AI) offered by Hackl (Bhaduri 2021). Robotics, Autonomous Vehicles and Smart Cities all require at least some level of AI so its relevance to the Metaverse is obvious. What is interesting is that Rafael Brown (Hackl 2021) has seemingly applied Larry Tesler’s Theorem (ca. 1970) that, AI is whatever machines have not done yet, to the Metaverse. Perhaps that the Metaverse will be combined with AI and AI is such a futuristic term, means the Metaverse becomes a futuristic term as well.

It should be noted that there was no need to advance the candidate definition, beyond the currently accepted scientific one, in order to combine the Metaverse with other technologies. Yes, the Metaverse might be the behind the scenes resource, for spatial computing, for all the in the future. If, for every new technology connected to the Metaverse, we change the definition of the Metaverse, then the term will indeed be as futuristic as Larry Tesler’s Theorem about AI. Nevertheless, the question that remains is, what must be resolved today so that the Metaverse can exist, as soon as possible, as an interconnected whole, in contrast to fragments.


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