The Metaphysics of the Metaverse
How does one represent the Ship of Theseus paradox (also known as the Grandfather's Axe paradox) with NFTs in the Metaverse? If one replaces the axe blade and the axe handle, is it still the same NFT?
The Ship of Theseus paradox is a foundational principle of the metaphysics of identity that dates back to Heraclitus and Plato circa 500 BCE. If one replaces the boards in a ship (or the axe blade and axe handle of an axe) is it still the same ship (or axe)? If the Metaverse cannot represent the paradox, it cannot represent and emulate reality.
"Lead us from the unreal to the real"
The Metaverse digitally represents both real and virtual objects on a Blockchain. Paradoxes that exist in the real world must be equally representable through NFTs and operations on NFTs. An object represented in the Metaverse must be arbitrarily and dynamically divisible or fusible with other objects on demand, as determined by the "laws of nature" in which the object exists in the respective Metaverse. While NFTs are immutable, the objects that they represent are not immutable and the NFTs must reflect the transformations that occur to the real object or are permitted by objects in the Metaverse.
Consider a shirt in the Metaverse for which the owner chooses to move a button to another shirt in the Metaverse, or a thread, or a speck of dust, or the impurity in one silk thread. Or consider a container of Himalayan salt for which the owner wants to separate the sodium chloride from the 84 other trace minerals. It's not practical nor scalable to divide space in the Metaverse to the Planck length volumes or to track the all of the components of objects at the subatomic level. And it's also unnecessary. Instead of tracking the composable objects at arbitrarily fine and/or limited granularity, an operation associated with the NFT must provide the ability to respond to a request for an arbitrary transformation.
If the rules for permissible actions were associated with, encoded in or calculated by NFT Smart Contracts, NFT Smart Contracts would permit fusion or fission of an object on demand, when queried, and at the granularity requested. The Smart Contract would allow the Blockchain network and validators to divide, combine or copy the NFT, as allowed by the contract, to represent the transformation of the corresponding object, and to generate a new object or objects representing the final disposition of the transformation, ideally at the coarsest granularity that can accurately represent the final state. For example, an NFT representing a quantity of Himalayan salt would be transformed to an NFT representing a chemically appropriate quantity of sodium chloride and an NFT representing an equally appropriate quantity of trace minerals, not N mole NFTs of NaCl and M mole NFTs of KCl, Q mole NFTs of Mg, etc.[1]
The Smart Contract program (possibly in conjunction with an external "oracle") would determine if an object transition is allowed using a combination of predefined decision tree, predefined allowed transitions, predefined rejected transitions, predefined transitions based on the identities of the entities in the transaction (principals and agents), transitions based on cached information from recent, previous transitions, transitions based on cached transitions from other, similar objects handled by the Blockchain miner or validator, transitions based on cached transitions from other, similar objects handled by the Blockchain network, transitions based on artificial intelligence (AI) inference, and transitions based on an external, central authority. The Blockchain network would agree, through consensus of multiple miners or validators achieving the same result, that the transformation is valid.
On a private Blockchain network, the decision making authority is clearer and the decision making process for permitted transformations is simpler (e.g., consensus unnecessary), but the scalability issues driving a more efficient solution remain. It is not practical for the Metaverse to represent and track the finest granularity of every object. Video games follow the same principle to only generate what can be seen when it is observed. The Metaverse must follow the same principle of object representation: NFTs should be created and correspond to the coarsest granularity that represents the object and its ownership necessary for the required, observable action.
The current NFT ecosystem provides the concept of fractional ownership or fractional value, but that corresponds to portions the NFT representing the object or a quantity of an unchanging object, not characteristics or components of the object itself mutating. The ecosystem also has been extended to composability of NFTs, but applied in a predefined, large granularity sense. Operations on NFTs (Smart Contracts) must intermediate and arbitrate these operations on demand.[2,3,4,5]
An object in the Metaverse has properties that can be bought, sold, rented, lent, transferred, loaned, moved, or copied to one or more other objects based on the rules defined for the object. If the property is not shareable, then the object loses that component. If the property is shareable, then the entity receives a copy with a subset of the permitted, shareable properties. The allowed sub-properties of the object can be determined by the creator of the class of objects, by the owner of the object, or by consensus among the NFT and/or Blockchain market (Metaverse) in which the object exists.
Components that are shareable allow NFTs to represent non-exclusive behaviors. A work of art can be loaned to a museum, giving the museum the limited rights to exhibit the work of art, and everyone who enters the exhibition gallery of the piece of art is granted the limited rights to interact with the artwork without the other rights of ownership. A hotel guest is granted the limited rights to use the contents of a hotel room represented by an NFT, which is a fraction of the hotel, without owning a fraction of the hotel and all of the devolved benefits, liabilities, and responsibilities.
The NFTs on the Blockchain represent the state of ownership of objects or components of objects. The Blockchain is updated when a transition of ownership occurs, but the arbitrarily complex object represented by the NFT can be acted upon in ways that don't change ownership and without an action that triggers an event on the Blockchain. An agent or entity can inquire of the Metaverse to materialize an arbitrary view of the object, and multiple agents can observe different aspects, characteristics, and granulatiries of the object simultaneously. For example, one person in an art gallery can view an entire painting while another person examines a specific brush stroke of the same painting.
This behavior of multiple views that hypothetically could result in a transition can be expanded as a method of optimization where the Metaverse can proactively allow multiple agents to propose an action on an object that would cause a change in ownership of the object. If the actions are not mutually-exclusive, any or all eventually can complete. If any of the actions are mutually-exclusive, then the object must conform to the "laws of nature" for that Metaverse and only one action succeeds. In a large, distributed Metaverse environment, this permits speculative actions concurrently proposed by many agents with the hope of non-conflicting success instead of serializing the activities of the agents, which makes the entire Metaverse less scalable and less responsive. Examples of this include an e-commerce purchase where the online vendor speculates that an item with limited supply remains in stock and available until the moment of purchase, when database ACID properties must be applied so that the transactions are self-consistent in the ledger.
The human perception of the environment requires an observer. Computer vision needs an embodied observer to interpret its input. Some optical illusions rely on human assumptions about the geometry and composition of the real world mapped to our visual perception. Each person applies his or her own attention and focus to perceive the world differently, from his or her own perspective. The Metaverse similarly needs a mechanism to integrate and record the multitude of individual perceptions of objects. The objective reality is one representation of the object, but each individual may need to perceive and interact with a unique, private aspect of the same object, with more or less granularity, depending on his or her attention, biases, and actions. The Blockchain for the Metaverse is providing the underlying information (objective truth) for a multi-agent simulation where each agent may require a different view or aspect, i.e., a different granularity of the data. Some agent inquiries and actions refer to the composited object and some agent inquiries and actions require the individual components of the object or a composite of multiple objects.
Even when the object cannot or should not be reconstituted, the Metaverse and Blockchain network can maintain a cache of the lower-granularity view constructed while proactively scanning for fragments of objects that could be merged. The presentation to the user may correspond to a different configuration and composition than the object or objects represented by the NFTs. The implementation of a Metaverse as NFTs on a Blockchain must continually balance the amount of granularity of an object represented on the Blockchain versus the amount of granularity encapsulated within the object. A single object in the Multiverse could be represented as a composite of multiple NFTs or an internally granular and complicated object could be represented as a single NFT. Depending on the actions or transformations on the object, the ownership, the history of the object, and any proactive scavenging, each object can have an arbitrarily complicated relationship with the NFTs associated with it. The relationship between the representation or materialization of objects and the NFTs on the Blockchain must dynamically adapt to the ownership and the actions being performed; it's not always a one-to-one mapping.
With the ability to exchange and/or replace tokens based on the mutability of the underlying object (fusion and fission), it is computationally more efficient for the Metaverse to proactively scavenge and/or reap objects whose underlying representation is fragmented (individual components unlikely to be used individually in the near future or separate ownership no longer relevant). Each NFT should correspond to the maximal complete subgraph of the components of the object that is necessary and sufficient for the operation to be performed on the object and the ownership of the components.
This capability of the Metaverse provides an important motivation to incorporate AI into the Blockchain, NFTs, Smart Contracts and the Metaverse. It is impractical to predefine all transitions and equally impractical to request the intervention of a human expert for all transition. The mechanism for determining the outcome of the NFT Smart Contracts needs to scale with the number of objects while providing "answers" in a timely manner to maintain the transaction velocity of the Metaverse. This can be an important use case for Neuro-symbolic AI that is able to reason about the objects in the Metaverse, their behaviors and the requested transitions. It needs both the knowledge base of "common sense" about the objects in the Metaverse and also needs to understand the transitions that are attempted so that it may successfully navigate the requests without damaging the value and consistency of the particular Metaverse in which the objects are represented.
The Blockchain will track the history and origins of the components, but the linear ledger nature of the Blockchain introduces some challenges. Incrementally appending and merging each component scales with the number of components, which is expensive at fine granularity. Building up a complicated object by hierarchically merging pairs of objects remains expensive and is expensive to search if the history must be analyzed. An efficient representation requires an NFT token that can represent a hierarchical merge that is equivalent to the hierarchical graph of the components of the object itself.
As NFTs and the Metaverse confront the complexities of representing real world objects and the inherent philosophical paradoxes of reality, NFTs must incorporate transformations that mediate between NFTs and the metamorphosing objects that they represent. Smart Contracts or other algorithms and characteristics associated with the NFT that allow an NFT to be replaced by another NFT representing the fission or fusion result of such a transformation on demand, when the object is required to mutate in a manner, is an efficient and scalable solution. This approach will allow NFTs to efficiently represent the hierarchical graph of components of an object and the complex set of operations and transformations that can be performed on the object at any level of granularity permitted by the Metaverse in which it is embedded.
The complicated relationship between composited objects in the Metaverse and the NFTs representing the objects on the Blockchain opens significant and exciting opportunities for additional innovation in this ecosystem. Let's build some ships!
[1] 1 mole = 6.022 x 10**23 elementary entities.
[2] ETH EIP 864 Divisible non-fungible tokens.
[3] ETH EIP 998 Composable non-fungible tokens.
[4] ETH EIP 1634 Re-fungible tokens.
[5] Chainlink 2.0: Next Steps in the Evolution of Decentralized Oracle Networks. Chainlink Labs. https://chainlinklabs.com/