WandaVision: The Ship of Theseus and Identity Metaphysics

Endurantism holds that objects are three-dimensional entities that exist wholly at each moment of their existence. Perdurantism holds that objects are four-dimensional entities that exist as extended through time, with different temporal parts at different times. These are the two main competing theories about how objects persist through time. Perdurantism resolves the problem of persistence by treating objects as four-dimensional 'space-time worms' composed of temporal parts. When we say 'this car is blue,' we are referring to a temporal part of the car. When the car changes color, it's not the same object changing properties but rather different temporal parts having different properties. Endurantism resolves the problem by treating properties as temporally indexed—'the car is blue on Tuesday' and 'the car is red on Wednesday' are different properties, so there is no contradiction. The coincidence paradox involves two objects occupying the same space at the same time, such as a lump of clay and a statue made from that clay. Perdurantism resolves this by treating the clay and statue as different four-dimensional objects. Personal identity can be understood as a special case of composition over time. Memory is often proposed as a criterion for personal identity, but this criterion faces problems: memory can fade, and we may lose connection to our past selves. Alzheimer's disease raises questions about personal identity because it involves the loss of memories and personality. Derek Parfit's teletransportation thought experiment involves a machine that scans a person, destroys the original, and reconstructs an identical copy at another location. The question is whether the copy is the same person as the original. One philosophical position holds that identity is not a real metaphysical fact but merely an illusion of consciousness. The metaphysics of time (presentism, eternalism, growing block theory) has important implications for the metaphysics of persistence. For example, perdurantism is compatible with eternalism but incompatible with presentism.

Persistence through time combines discussions of time (A-series and B-series, McTaggart's argument) with physical objects and their constitution. Endurance is the intuitive view that objects exist entirely at each moment—a person as a baby, university student, and adult are all the same entity that existed wholly at each time. Perdurance is the four-dimensionalist view that objects persist through time by having temporal parts, like a spacetime worm with slices at each moment. Exdurance is a newer view where objects have counterparts rather than being identical to their temporal parts. These theories address how objects persist through time and set up debates about personal identity.

Perdurantism (the view that objects persist through time as four-dimensional worms composed of temporal parts) provides a more coherent account of time travel than endurantism (the view that objects are wholly present at each moment), because endurantism leads to logical contradictions when applied to time travel scenarios where a person would be literally identical to their younger self yet possess different properties (like having a beard versus not having a beard); additionally, presentism (the view that only the present moment exists) can accommodate time travel by understanding that present actions make it the case that one existed in the past, rather than traveling to a non-existent past.

In metaphysics, the debate between perdurantism and endurantism concerns how objects persist through time: perdurantism (worm theory) holds that objects are four-dimensional entities composed of temporal parts, while endurantism holds that objects are wholly present at every moment of their existence. Armstrong argues that ordinary particulars exhibit loose identity (continuity of existence, resemblance, and causality) rather than strict philosophical identity, and he presents this as a fundamental question about whether objects have temporal parts or are entirely present at each moment.

This section examines two competing views on how objects persist through time. Substantialism (endurantism) holds that objects are fully present at each moment, like beads on a timeline string, without temporal parts. Perdurantism (four-dimensionalism) treats time as a dimension alongside space, meaning objects have temporal parts and we only ever encounter segments of them. These views address how we remain numerically identical despite constant physical changes, such as losing fingernails or aging.

Mereological essentialism is the view that composite objects are conceptually prior to their parts. Under this theory, composite objects exist necessarily, and their parts are merely concrete instantiations of abstract objects that encode all the properties of the composite. The concrete object is made when the requisite parts come together.

Essentialism is a philosophical view within mereology that objects exist not just through the organization of their parts, but through their essential parts. These are the parts without which the object would cease to exist or lose its identity. For the Ship of Theseus, essentialists might argue that structural components are essential, and their removal would destroy the ship's identity. This view suggests identity is tied to specific physical components rather than mere continuity.

Roderick Chisholm, a prominent 20th-century metaphysician, argues that persons are not identical with their physical bodies (which constantly replace all their parts over time, with every atom renewed approximately every seven years), but rather with tiny physical particles within the brain that never change parts; this view, called mereological essentialism, holds that a person persists only if they maintain the same minimal physical component throughout their existence, distinguishing between the physical organ (brain) that enables consciousness and the conscious subject (the tiny particle) that constitutes personal identity.

Essentialism is the philosophical view that everything has an inherent essence—a set of necessary properties that define what something is. Plato and Aristotle believed that for any object or concept, there exists a core set of essential properties that must be present for it to be classified as that thing. For example, a knife's essential property is its blade; changing the handle to plastic doesn't change its nature, but changing the blade would transform it into something entirely different. This concept was considered nearly irrefutable until the end of the 19th century and remains common in everyday thinking today.

Roderick Chisholm distinguishes between loose identity (the common-sense notion where we say objects like ships or computers remain 'the same' despite part replacements) and strict identity (which requires adherence to the Indiscernibility of Identicals principle, meaning identical objects must share all properties including parts). Chisholm argues that strict identity always involves intact persistence—objects that never undergo part replacement—making him a mereological essentialist. While conventions can resolve practical questions about which ship or computer is 'the same,' strict identity presupposes the existence of genuinely persisting objects. This framework creates puzzles for persons, as demonstrated by cases involving fission and memory loss, which Chisholm acknowledges require additional philosophical analysis.

The mind transfer process involves copying consciousness from one body to another using cortex chips. The process requires looping back the activity manifested by the current cortex chip, running it through an amplifier, feeding it into a new chip, and syncing it. This creates a situation where the original person is not destroyed but rather copied, resulting in two versions of the same person. The sleeping Simon in the seat was copied, and now the consciousness exists in the new body. This raises profound philosophical questions about identity, continuity of self, and what constitutes the 'real' person. The original body remains, but the consciousness has been duplicated, creating an ethical dilemma about whether to kill the original body or leave it alive. A significant ethical dilemma arises when consciousness is transferred between bodies. The decision involves whether to kill the original body (which would be suicide or murder) or leave it alive (which would result in the original person being left behind alone). The dilemma is that the person who was copied may continue to exist in the original body, while the consciousness that was transferred now exists in the new body. The question of whether to kill the original body or leave it alive represents a profound moral choice about the value of the original self versus the new existence. When consciousness is transferred to digital copies, several existential questions arise. The person who was copied may wonder if they are truly alive or just a digital copy. They may question whether there is a heaven full of redundant copies of the same people. They may wonder if someone up there would call them an imposter. The question of whether the digital copy is truly the same person or just a copy raises profound questions about identity, consciousness, and what makes us human. The uncertainty about whether the digital copy is truly alive or just a simulation creates an existential crisis. The person who was copied may feel like an imposter, questioning whether they truly exist or are merely a simulation of consciousness.

A fundamental philosophical question arises from transhumanist consciousness uploading: if consciousness is digitized and transferred to a machine, is the resulting digital entity truly the original person? The speaker argues that consciousness is not localized in the brain but distributed throughout every cell and even every particle of the body. Quantum physics, particularly the double-slit experiment, demonstrates that particles exhibit wave-particle duality depending on whether they are observed, suggesting an underlying consciousness connecting all matter. Since humans are composed of particles, consciousness should be distributed throughout the entire body rather than confined to the brain, making brain-only consciousness extraction impossible. The ego (self-identity) is fragile and constantly changing, shaped by external influences and prone to collapse. Descartes' famous statement 'I think, therefore I am' identifies the ego as the root of identity, but this is merely a constructed self rather than the true self.

If consciousness can be uploaded to a computer, would that still be you or just an AI-powered simulation of you? Every human who has ever lived has faced death as an unstoppable force, but what if death is just another problem to be solved? Scientists are already working on mind uploading, brain emulation, and consciousness transfer. If your mind exists in a computer, is it really you or is it just a copy—a ghost in the machine? Could we live in a digital paradise free from disease, pain, and aging, or would we become prisoners of a virtual existence with no escape? And if AI has control over our very identity, who controls us? Some believe transhumanism is the next step in human evolution—a path to ultimate knowledge, power, and immortality. Others fear it is a dangerous experiment that could strip away what makes us human. If we merge with AI, become machines, and transcend biology, are we still human anymore?

Many transhumanists are invested in mind uploading—extracting individual consciousness and putting it onto software. Some envision living as robots, others as Mars rovers, and some as free-floating consciousness extending infinitely through time and space. The philosophical question raised is whether such a state constitutes existence as a god or as nothing at all.

A key transhumanist goal is uploading the informational content of human brains or minds into massive computing systems or digital clouds. On this materialist view of human beings, this would eliminate the need for physical bodies, which inevitably fail and return to dust. Living forever in digital form constitutes the transhumanist eschatology or ultimate salvation.