Glossary Terms
he study of simulated reality crosses philosophy, computer science, artificial intelligence, consciousness studies, virtual reality, and speculative technology. This glossary establishes a common vocabulary for discussing these subjects.
Some entries describe established philosophical or technological concepts. Others, identified as Society Terms or Society Models, are terminology used by the Simulation Theory Society to organize questions and possible simulation scenarios. They should not be interpreted as evidence that our reality is simulated.
Allegory of the Cave
A thought experiment presented by Plato in The Republic in which prisoners understand reality only through the shadows visible from their confined perspective. The allegory explores the difference between appearance and underlying reality and has become a useful analogy for discussions of simulated worlds.
Within simulation studies, it poses a simple question: If everything you had ever experienced were only a representation of something beyond your perception, what would cause you to turn around?
Stanford Encyclopedia of Philosophy — Plato
Ancestor Simulation
A simulation containing detailed representations of an earlier civilization or its inhabitants.
Ancestor simulations are central to Nick Bostrom’s 2003 Simulation Argument. Bostrom considers whether technologically mature civilizations might possess sufficient computing power to run large numbers of simulations of their evolutionary history containing simulated conscious observers.
See also: Simulation Argument, Posthuman Civilization, Substrate Independence.
Architect
The individual, intelligence, organization, or system responsible for designing and building a simulated environment.
Within the Society’s terminology, the Architect is distinct from the Creator. An Architect writes or constructs the rules and infrastructure of the world; a Creator initiates or instantiates a particular simulation using that architecture.
A simulation could theoretically have many Architects and many Creators.
Artificial Intelligence (AI)
A broad category of machine-based systems that infer from inputs how to generate outputs such as predictions, content, recommendations, or decisions that can affect physical or virtual environments.
AI is relevant to simulation studies because increasingly sophisticated artificial agents demonstrate that complex behavior can be generated computationally. This does not, by itself, demonstrate that current AI possesses consciousness.
Avatar
A representation through which a Player interacts with a simulated or virtual environment.
An avatar does not necessarily resemble the Player controlling it. Its appearance, abilities, memories, physical characteristics, and limitations could theoretically be determined entirely by the simulated environment.
Base Reality
The hypothetical fundamental level of reality that is not itself simulated.
If our universe were simulated, the environment containing the system responsible for our simulation would be one level above ours—but it would not necessarily be base reality. That environment could itself be simulated.
This creates one of the central problems of nested simulation:
How would we know when we had reached the bottom?
Brain in a Vat
A philosophical thought experiment in which a brain receives artificially generated sensory information and consequently experiences a world that does not correspond to its physical surroundings.
Modern versions are strongly associated with philosopher Hilary Putnam, although they belong to a much longer tradition of skeptical thought experiments. The scenario also became a major conceptual precursor to The Matrix.
Internet Encyclopedia of Philosophy — Brain in a Vat
Consciousness
The capacity for subjective awareness or experience.
Consciousness represents one of the largest unresolved questions surrounding simulated people. A computer may reproduce behavior without establishing that the entity producing that behavior has an internal subjective experience.
The possibility of simulated conscious observers therefore depends partly upon unresolved questions in philosophy of mind and cognitive science.
Creator
The person, civilization, intelligence, organization, or system responsible for initiating a particular simulation.
The Society distinguishes a Creator from an Architect:
The Architect builds the program. The Creator runs it.
For example, an advanced civilization might inherit simulation technology designed centuries earlier. The civilization initiating a new world would be its Creator without necessarily being the Architect of the underlying system.
Neither term implies supernatural creation.
Digital Twin
A digital representation of a physical object, process, environment, or system designed to reproduce relevant characteristics or behaviors of its physical counterpart.
Digital twins demonstrate one practical reason for creating increasingly sophisticated simulations: rather than experimenting directly on the real system, researchers can model possible conditions and outcomes computationally.
Emergent Behavior
Complex behavior or patterns that arise from interactions among simpler components rather than being individually predetermined by a designer.
Emergence raises an important question for simulated reality: Would an Architect actually need to program everything that happens?
A sufficiently complex system might instead operate from fundamental rules while civilizations, economies, relationships, conflicts, and other phenomena emerge from interactions among its inhabitants.
Framework
The Society’s structured method for investigating questions surrounding reality and the Simulation Hypothesis.
Rather than establishing what members must believe, The Framework provides a common method of inquiry organized around four areas:
Observation — Consciousness — Inquiry — Continuity
Its purpose is to separate observation from assumption and encourage continued investigation rather than predetermined conclusions.
Consciousness Begins Discovery.
Free Will
The capacity of an individual to make choices that are meaningfully their own rather than entirely determined by prior causes or external control.
Simulation scenarios add another dimension to the traditional problem of free will. If an environment operates according to programmed rules, its inhabitants could still potentially make independent decisions within those constraints.
The existence of rules does not automatically establish the absence of agency—just as the physical laws of our observable universe do not by themselves settle the philosophical debate over free will.
The Interface
The hypothetical mechanism through which information passes between a simulated environment and something outside it.
An Interface might allow a Player to enter the simulation, an Observer to collect information, or an external system to alter conditions inside the simulated world.
The term does not require a literal screen, headset, or physical device. It describes the boundary through which two levels of reality exchange information.
Matrix
A popular shorthand for a completely immersive artificial reality, derived primarily from the 1999 film The Matrix.
Its central premise resembles the philosophical Brain-in-a-Vat problem: human beings experience a convincing environment while their physical bodies exist somewhere entirely different.
Within the Society, Matrix should remain a cultural reference rather than a technical term.
Metaverse
A broad term used to describe persistent digital environments in which people interact through virtual identities or avatars.
Metaverse technologies are relevant to simulation studies because they demonstrate humanity’s growing interest in constructing persistent alternative environments for socialization, entertainment, commerce, creativity, and work.
A metaverse should not be confused with the Simulation Hypothesis: one is a technology humans are attempting to create; the other proposes that our experienced reality itself could be simulated.
Nested Simulation
A hypothetical simulation existing inside another simulation.
Suppose Civilization A creates Simulation B. The inhabitants of B eventually develop sufficient technology to create Simulation C. The inhabitants of C then create Simulation D.
Each population might regard its own environment as ordinary reality.
Nested simulations therefore complicate the meaning of base reality. Discovering that our world was simulated would establish only that another level exists—not that the newly discovered level is fundamental.
Non-Player Character (NPC)
Originally a video-game term describing a character that is not controlled by a human player.
Within simulation discussions, NPC is sometimes used speculatively to describe an artificial inhabitant of a simulated environment.
The Society uses NPC strictly as a thought experiment concerning artificial agency and consciousness. It should not be used to claim that particular real people are unconscious, artificial, or somehow less human.
Observer
A hypothetical entity that monitors events occurring within a simulation without necessarily directly controlling them.
An Observer could be a researcher studying an ancestor simulation, an automated system collecting information, or an audience watching events for entertainment.
This should not be confused with the technical meaning of observation in quantum mechanics. Quantum measurement does not establish that conscious beings are watching our universe from outside it.
Player
An entity originating outside a simulated environment that temporarily controls, inhabits, or interacts through a representation inside it.
The distinction between a Player and an NPC is therefore based on origin:
Player → consciousness or control originates outside the simulation.
NPC → entity originates within the simulation.
A Player’s representation inside the simulation could be called an avatar.
Posthuman Civilization
In Bostrom’s Simulation Argument, a civilization that has reached a sufficiently advanced technological stage to possess enormous computing capabilities.
Bostrom’s argument considers whether such civilizations might use a fraction of those resources to run large numbers of simulations containing observers like their ancestors.
Preservation Simulation
A speculative model in which simulated reality exists primarily to preserve conscious human life or civilization after conditions outside the simulation have become dangerous or uninhabitable.
Rather than recreating deceased ancestors, its participants could theoretically be surviving biological humans connected to an artificial environment.
Different governments, corporations, communities, or other groups might maintain independent simulations, potentially producing hundreds or thousands of isolated artificial worlds.
There is currently no evidence that humanity inhabits a Preservation Simulation.
Reality
The world or state of affairs that actually exists, independent of whether our understanding of it is complete.
Simulation studies complicate the everyday distinction between “real” and “fake.” If conscious beings genuinely experience relationships, pain, pleasure, memory, and time inside a simulated environment, their environment could still constitute their lived reality even if it is not base reality.
This makes reality and base reality importantly different terms.
Sandbox Simulation / Video Game Simulation
A speculative model in which a simulated world exists primarily for experimentation, entertainment, creativity, or play rather than historical research or preservation.
An external Player might control a specific character, manipulate the environment, introduce events, or simply observe what emerges.
The model raises questions including whether the simulation has an objective, whether time operates at the same rate inside and outside it, whether its inhabitants are conscious, and whether Players can enter and leave the environment.
I would officially use Sandbox Simulation throughout the Resources section and list Video Game Simulation as an alternate name. It sounds considerably more credible while describing the same idea.
Simulation
A representation of a system that reproduces selected properties or behaviors of that system.
A simulation does not necessarily reproduce every detail of what it represents. Weather models, flight simulators, economic models, virtual environments, and video games all simulate different aspects of systems at dramatically different levels of complexity.
Simulation Argument
The philosophical argument introduced by Nick Bostrom in his 2003 paper Are You Living in a Computer Simulation?
Bostrom argues that at least one of three propositions is true: humanity is very unlikely to reach a technologically mature posthuman stage; posthuman civilizations are extremely unlikely to run significant numbers of ancestor simulations; or observers like us are very likely simulated.
The Simulation Argument is not a claim that scientists have discovered evidence proving our universe is simulated.
Read Nick Bostrom’s original paper
Simulation Creationism
A contemporary creator-centered interpretation of simulated reality associated with Nir Ziso.
It attempts to connect simulation concepts with questions traditionally addressed by creationism and theology. It is distinct from Bostrom’s probabilistic Simulation Argument and should not be presented as an established scientific theory.
For your site, I would categorize this under Alternative Models & Interpretations rather than alongside established scientific concepts.
Simulation Hypothesis
The proposition that the reality experienced by humans could be generated by an artificial or computational system rather than constituting the fundamental level of existence.
The term should be distinguished from Bostrom’s Simulation Argument, which is a specific philosophical argument concerning the probability of simulated observers under particular assumptions.
Simulation Theory
A popular umbrella term for ideas proposing that experienced reality may be simulated.
The Society uses Simulation Theory as the broader cultural category and Simulation Hypothesis when discussing the proposition more precisely.
This distinction is useful because “simulation theory” also has unrelated technical meanings in areas of philosophy and psychology.
Simulator
The system or infrastructure that actually runs a simulation.
Within the Society’s vocabulary:
Architect → designs it.
Creator → initiates it.
Simulator → runs it.
Interface → connects to it.
Player → enters or controls something within it.
Observer → watches it.
I think this little hierarchy should actually appear as a diagram elsewhere on the Resources page. It makes your terminology unusually easy to understand.
Substrate Independence
The hypothesis that mental processes do not necessarily depend upon a particular physical material, such as biological neurons, and could theoretically be implemented on another suitable substrate.
Bostrom identifies substrate independence as an assumption underlying the possibility of simulated minds. His Simulation Argument therefore depends on assumptions about consciousness that have not been experimentally established.
Virtual Reality (VR)
Technology designed to produce an immersive computer-generated environment experienced from a user’s perspective.
VR is not evidence for the Simulation Hypothesis. Its relevance is technological: it demonstrates that humans are already attempting to create increasingly immersive artificial environments that can be experienced from within rather than merely observed on a screen.
Virtual World
A computer-generated environment in which users or artificial agents can interact with one another and their surroundings.
Unlike a conventional video game, a virtual world may be persistent—continuing to exist and change while individual users are absent—and may emphasize social interaction, creation, commerce, or community rather than a specific objective.