An exploration of the philosophical concept of metaphysical identity, using numerous variations on the infamous Ship of Theseus thought experiment.
Video interview with Keith Wiley
Note: a separate text interview is below.Keith Wiley is the author of A Taxonomy and Metaphysics of Mind-Uploading, available on Amazon.
The ship of Theseus, also known as Theseus’ paradox, is a thought experiment that raises the question of whether an object that has had all of its components replaced remains fundamentally the same object. The paradox is most notably recorded by Plutarch in Life of Theseus from the late first century. Plutarch asked whether a ship that had been restored by replacing every single wooden part remained the same ship.
The paradox had been discussed by other ancient philosophers such as Heraclitus and Plato prior to Plutarch’s writings, and more recently by Thomas Hobbes and John Locke. Several variants are known, including the grandfather’s axe, which has had both head and handle replaced.
See more at Wikipedia…
Note this is not a transcription of the video/audio interview.
The Ship of Theseus Metaphor
Adam Ford: Firstly, what is the story or metaphor of the Ship of Theseus intended to convey?
Keith Wiley: Around the first century AD, Plutarch wrote several biographies, including one of the king Theseus entitled Life of Theseus, in which he wrote the following passage:
People sometimes erroneously believe that Plutarch presents the scenario (replacing a ship piecemeal style until all original material is absent) with a conclusion or judgment, i.e., that it makes some prescription of the “correct” way to interpret the scenario (as to, yes or no, is the ship’s identity preserved). However, as you see from the passage above, this is not the case. Plutarch left the question open. He mere poses the question and leaves it to the reader to ruminate on an actual answer.
The specific questions in that scenario are:
- Does identity require maintaining the same material components? Aka, is identity tied and indicated by specific sets of atoms?
- If not, then does preservation of identity require some sort of temporally overlapping sequence of closely connected parts?
The more general question being asked is: What is the nature of identity? What are its properties? What are its requirements (to claim preservation under various circumstances)? What traits specify identity and indicate the transformations under which identity may be preserved and under which it is necessarily lost?
Here is a video explainer by Keith Wiley (intended to inspire viewers to think about identity preservation)
Adam Ford: How does this story relate to mind uploading?
Keith Wiley: The identity of relatively static objects, and of objects not possessing minds or consciousness, is an introduction to the thornier question of metaphysical personal identity, i.e., the identity of persons. The goal in considering how various theories of identity describe what is happening in the Ship of Theseus is to prime our thinking about what happens to personal identity of people in analogous scenarios. For example, in a most straightforward manner, the Ship of Theseus asks us to consider how our identity would be affected if we replaced, piecemeal style, all the material in our own bodies. The funny thing is, this is already the case! It is colloquially estimated that our bodies turn over their material components approximately every seven years (whether this is precisely accurate is beside the point). The intent is not that a conclusion drawn from the Ship of Theseus definitively resolves the question concerning personal identity, because the former is a much simpler scenario. The critical distinction is that people are more obviously dynamic across time than static physical objects because our minds undergo constant psychological change. This raises the question of whether some sort of “temporal continuity” is at play in people that does not take effect in ships. There is also the question of whether consciousness somehow changes the discussion in radical ways. So the Ship of Theseus is not conclusive on personal identity. It is just a way to get us started in thinking about such issues.
Adam Ford: Fishing for clarification on how you use the term ‘identity’, Robin Hanson (scenario of uploads in the future in Age of Em) enquired about what kind of identity concept you are interested in. That is, what function do you intend this concept to serve?
Keith Wiley: Sure. First, and this might not be what Robin meant, there are different fundamental kinds of identity, two big ones being quantitative and numerical. Two things quantitatively identified possess the same properties, but are not necessarily “the same entity”. Two things numerically identical are somehow “the same thing”, which is problematic in its phrasing since they were admitted to be “two things” to begin with. The crucial distinction is in whether numerical identity makes any difference, or whether quantitative identity is all the fundamentally matters.
For me, I phrase the crucial question of personal identity relative to mind uploading in the following way: Do we grant equal primacy to claims to the original single identity to all minds (people) who psychologically descend from that common ancestral mind (person)? I always phrase it this way: granting primacy in claims to a historical identity. Do we tolerate the metaphysical interpretation that all descendant minds are equal in the primacy of their claim to the identity they perceive themselves to be? Alternatively, do we disregard such claims, dictating to others that they are not, in fact, who they believe themselves to be, and that they are not entitled to the rights of the people they claim to be? My concern is of:
bias (differing assignments of traits to various people),
prejudice (differing assignments of values, claims, or rights resulting from bias),
and discrimination (actions favoring and dismissing various people, resulting from prejudices).
Adam Ford: Is ‘identity’ the most appropriate word to be using here?
Keith Wiley: Well, identity certainly doesn’t seem to fully “work”. There’s always some boundary case or exception that undermines any identity theory we attempt to assign. My primary concern, such as it is on an entirely abstract philosophical musing (at this point in history when mind uploading isn’t remotely possible yet) is only secondarily the nature of identity. The primary concern, justified by those secondary aspects of identity, is whether we should regard uploads in some denigrated fashion. Should we dismiss their claims that they are the original person, that they should be perceived as the original person, that they should be treated and entitled and “enrighted” as the original person? I don’t just mean from a legal standpoint. We can pass all sorts of laws that force people to be respectful, but that’s an uninteresting question to me. I’m asking if it is fundamentally right or wrong to regard an upload in a denigrated way when judging its identity claims.
Ontology, Classification & Reality
Adam Ford: As we move forward the classification of identity will likely be fraught with struggle. We might need to invent new words to clarify the difference between distinct concepts. Do you have any ideas for new words?
Keith Wiley: The terminology I generally use is that of mind descendants and mind ancestors. In this way we can ask whether all minds descending from a common ancestral mind should be afforded equal primacy in their claim to the ancestral identity, or alternatively, whether there is a reasonable justification to exhibit biases, prejudices, and discriminations against some minds over such such questions. Personally, I don’t believe any such asymmetry in our judgment of persons and their identity claims can be grounded on physical or material traits (such as whose brain is composed of more matter from the ancestral brain, which comes up when debating nondestructive uploading scenarios).
Adam Ford: An appropriate definition for legal reasons?
Keith Wiley: I find legal distinctions to be uninteresting. It used to be illegal for whites and blacks to marry. Who cares what the law says from a moral, much less metaphysical, perspective. I’m interested in finding the most consistent, least arbitrary, and least paradoxical way to comprehend reality, including the aspect of reality that describes how minds relate to their mental ancestors.
Adam Ford: For scientific reasons?
Keith Wiley: I don’t believe this is a scientific question. How to procedurally accomplish uploading is a scientific question. Whether it can be done in a nondestructive way, leaving the original body and brain unharmed, is a scientific question. Whether multi-uploading (producing multiple uploads at once) is technically possible is a scientific question, say via an initial scan that can be multi-instantiated. I think those are crucial scientific endeavors that will be pursued in the future, and I participate in some of the discussions around that research. But at this point in history, when nothing like mind uploading is possible yet, I am pursuing other aspects, nonscientific aspects, namely the philosophical question of whether we have the correct metaphysical notion of identity in the first place, and whether we are applying identity theories in an irrational, or even discriminatory, fashion.
Implications for Brain Preservation
Adam Ford: Potential brain preservation (inc cryonics) customers may be interested in knowing the possible likely science of reanimation (which, it has been suggested, includes mind uploading) – and the type of preservation which will most likely achieve the best results. Even though we don’t have mind uploading yet – people are committing their brains to preservation strategies that are to some degree based on strategies for revival. Mummification? No – that probably won’t work. Immersion in saline based solution? Yeah for short periods of time. Plastination? Yes but only if it’s the connectome we are after… And then there is different methods of cryonic suspension that may be tailored to different intended outcomes – do you want to destructively scan the brain layer by layer and be uploaded in the future? Do you want to be able to fully revive the actual brain in the (potentially in a longer term future)?
Keith Wiley: People closer to the cryonics community than myself, such as some of my fellow BPF board members, claim that most current cryonics enthusiasts (and paying members or current subjects) are not of the mind uploading persuasion, preferring biological revival instead. Perhaps because they tend to be older (baby boomer generation) they have not bought into computerization of brains and minds. Their passion for cryonics is far more aligned with the prospect of future biological revival. I suspect there will be a shift toward those of a mind uploading persuasion as the newer generations, more comfortable with computers, enter the cryonics community.
As you described above, there are few categories of preservation and a few paths of potential revival. Preservation is primarily of two sorts: cryogenic and at least conceivably reversible, and room temperature and inconceivably reversible. The former is amenable to both biological revival and mind uploading. The latter is exclusively amenable to mind uploading. Why would one ever choose the latter option then? Simple: it might be the better method of preservation! It might preserve the connectome in greater detail for longer periods of time with lesser rates of decay — or it might simply be cheaper or otherwise easier to maintain over the long term. After all, cryonic storage requires cryonic facilities and constant nitrogen reintroduction as it boils off. Room temperature storage can be put on the shelf and forgotten about for millennia.
Adam Ford: What about for social (family) reasons?
Keith Wiley: This is closer to the area where I think and write, although not necessarily in a family-oriented way. But social in terms of whether our social contracts with one another should justify treating certain people in a discriminatory fashion and whether there is a rational basis for such prejudices. Not that any of this will be a real-world issue with which to tackle for quite some time. But perhaps some day…
Adam Ford: If the intended outcomes of BP are for subjective personal reasons?
Keith Wiley: I would admit that much of my personal interest here is to try to grind out the absolutely most logical way to comprehend minds and identity relative to brains, especially under the sorts of physical transformations that brains could hypothetically experience (Parfit’s hemispherical fission, teleportation, gradual nanobot replacement, freeze-slice-scan-and-emulate, etc.).
Adam Ford: In relation to appropriate definitions of ‘identity’ for scientific reasons – what are your thoughts on the whole map/territory ‘is science real’ debate? Where do you sit – scientific realism, anti-realism and structural realism (epistemic or ontic)? what’s your favorite?
Keith Wiley: I suppose I lean toward scientific realism (to my understanding: scientific claims and truths hold real truth value, not just current societal “perspective”, and further they can be applied to yet-to-be observed phenomena), although antirealism is a nifty idea (scientific truths are essentially those which we have yet to disprove, but expect to with some future overturning, or furthermore, unobserved phenomena are not reasonable subjects of scientific inquiry). The reason I don’t like the latter is it leads to antiintellectualism, which is a huge problem for our society. Rather than overturning or disregarding scientific theories, I prefer to interpret it as that we refine them, saying that new theories apply in corners where the old ones didn’t fit well (Newton’s laws are fine in many circumstances, but are best appended by quantum mechanics at the boundary’s of their applicability). Structural and ontic realism are currently vague to me. I’ve read about them but haven’t really grinded through their implications yet.
Adam Ford: If we are concerned about our future and the future of things we value we perhaps should ask a fundamental question: How do things actually persist? (Whether you’re a perdurantist or an endurantist – this is still a relevant question – see 5.2 ‘How Things Persist?’ in ‘Endurantism and Perdurantism’)
Keith Wiley: Perdurantism and Endurantism are not terms I have come across before. I do like the idea of conceptualizing objects as 4D temporal “worms”. I describe brains that way in my book for example. If this is the “right” way (or at least a good way) to conceive of the existence of physical objects, then it partially solves the persistence or preservation-of-identity problem: preservation of identity is the temporal stream of physical continuity. The problem is, I reject any physical requirement for explicitly *personal* identity of minds, because there appears to be no associated physical trait — plus that would leave open how to handle brain fission, ala Parfit, so worms just *can’*t solve the problem of personal identity, only of physical objects.
Adam Ford: Cybernetics – signal is more important than substrate – has cybernetics influenced your thinking? If so, how?
Keith Wiley: If by signal, you mean function, then I’ve always held that the functional traits of the brain are far more important (it not entirely more important) than mere material components.
Adam Ford: “signal is more important than substrate” – Yet the signal quality depends on the substrate – surely a ship’s substrate is not as tightly coupled to its function of moving across a body of water (wood, fiberglass, even steel will work) than a conscious human mind is to its biological brain. in terms of the granularity of replacement part – how much is needed?
Keith Wiley: Good question. I have no idea. I tend to presume the requisite level is action potential processing and generation, which is a pretty popular assumption I think. We should be open on this question at this time in history and current state of scientific knowledge.
Adam Ford: What level of functional representation is needed in order to be preserve ‘selfhood’?
Keith Wiley: Short answer: We don’t know yet. Long answer, it is widely presumed that the action-potential patterns of the connectome are where the crucial stuff is happening, but this is a supposition. We don’t know for sure.
Adam Ford: A Trolley Problem applied to Mind Uploaded Clones: As with the classic trolley problem, a trolley is hurtling down a track towards 5 people. As in the classic case, you can divert it onto a separate track by pulling a nearby leaver. However, suddenly 5 functionally equivalent carbon copies* of the original 5 people appear on the separate track. Would you pull the lever to save the originals but kill the copies? Or leave the originals to die, saving the copies? (*assume you just know the copies are functionally equivalent to the originals)
Keith Wiley: Much of my writing focuses on mind uploading and the related question of what minds are and what personal identity is. My primary claim is that uploads are wholly human in their psychological traits and human rights, and furthermore that they have equal primacy in their claim to the identity of the person who preceded an uploading procedure — even if the bio-original body and brain survive! The upload is still no less “the original person” than the person housed in the materially original body, precisely because bodies and material preservation are irrelevant to who we are, by my reckoning. If this is not the case, then how can we solve the fission paradox? Who gets to “be the original” if we split someone in two? The best solution is that only psychological traits matter and material traits are simply irrelevant.
So, for those reasons, I would rephrase your trolley scenario thusly: track one has five people, track two has five other people. Coincidentally, pairs of people from each track have very recently diverging memories, but the scenario is psychologically symmetrical between the two tracks even if there is some physical asymmetry in terms of how old the various material compositions (bodies) are. So we can disregard notions of asymmetry for the purpose of analyzing the moral or identity-preserving-killing implications of the trolley problem. It is simply “Five people on one track, five on another. Should you pull the lever, killing those on the diverted track to save those on the initial track?” That’s how I rephrase it.
Adam Ford: I wonder if the experiment would yield different results if there were 5 individuals on one track and 6 copies of 1 person on the other? (As some people suggest that copies are actually identical to the original – eg for voting purposes)
Keith Wiley: But they clearly aren’t identical in the scenario you described. The classic trolley problem has always implied that the subjects are reasonably alert and mentally dynamic (thinking). It isn’t carefully described so as to imply that the people involved are explicitly unconscious, to say nothing of the complexities involved in rendering them as physically static objects (preserved brains undergoing essentially no metabolic or signal-processing (action potentials) activity. The problem is never posed that way. Consequently, they are all awake and therefore divergent from one another, distinct individuals with all the rights of individual personhood. So it’s just five against six in your example. That’s all there is to it. People might suggest, as you said above, that copies are identical to each other (or to the original), but those people are just wrong.
So an interesting question then, is what if the various subjects involved actually are unconscious or even rigidly preserved? Can we say their psychological sequences have not diverged and that they therefore represent redundant physical instantiations of a given mind? I explore this exact question in my book by the way. I think a case could be made that until psychological divergence (until the brains are rolling forward through time, accumulating experiences and memories) we can say they are redundant in terms of identity and associated person-value. But to be clear, if the bio-original was statically preserved, then uploaded or duplicated, and then both people were put on the train tracks in their preserved state, physically identical, frozen with no ongoing psychological experience, then I would be clear to state that while it might not matter if we kill the upload, it *also* doesn’t matter if we choose the other way and kill the bio-original! That is the obvious implication of my reasoning here. And in your case above, if we have five distinct people on one track (let’s stay everyone involved is statically preserved) and six uploads of one of those people on the other track, then we could recast the problem as “five on one track and one on the other”. The funny thing is, if we save the six and revive them, then, after the fact, we have granted life to six distinct individuals, but we can only say that after we revive them, not at the time of the trolley experiment when they are statically preserved. So now we are speculating on the “tentative” split personhood of a set of identical but static minds based on a later time when they might be revived. Does that tentative individuality grant them individuality while they are still preserved? Does the mere potential to diverge and individualize grant them full-blown distinct identity before the divergence has occurred? I don’t know. Fascinating question. I guess the anti-abortion-choice and pro-abortion-choice debate has been trying to sort out the personhood of tentative, potential, or possible persons for a long time (and by extension, whether contraception is acceptable hits the same question). We don’t seem to have all agreed on a solution there yet, so we probably won’t agree in this case either.
Philosophy of identity
Adam Ford: Retention of structure across atomic change – is identity the structure, the atomic composition, the atomic or structural continuum through change, or a mixture?
Keith Wiley: Depends on one’s chosen theory of identity of course. Body theory, psychological theory, psychological branching theory, closest continuer theory, 4D spacetime “worm” theory. There’s several to choose from — but I find that some more paradox-prone than others, and I generally take that as an indication of a weak theory. I’m a branchest, although the distinction from worm theory is, on some accounts, virtually indistinguishable.
Adam Ford: Leibniz thought about the Identity of indiscernibles (principle in ontology that no two things can have all properties the same) – if objX and objY share all the same properties, are they the same thing? If KeithX and KeithY share the same functional characteristics are they the same person?
Keith Wiley: But do they really share the same properties to begin with, or is the premise unfounded? When people casually analyze these sorts of scenarios, the two people are standing there, conscious, wondering if someone is about to pass judgment on them and kill them. They are experiencing the world from slightly different sensorial vantage points (vision, sound, etc.) Their minds are almost certainly diverged in their psychological state mere fractions of a second upon regaining consciousness. So they aren’t functionally identical in the first place. Thus the question is flawed, right? The question can only be applied if they are unconscious and rigidly preserved (frozen perhaps). Although I believe a case could be made that mere lack of consciousness is sufficient to designate them *psychologically* identical even if they are not necessarily physically identical due to microscopic metabolic variations — but I leave that subtly as an open question for the time being.
Adam Ford: Here is a Symmetric Universe counterexample – Max Black – two distinct perfect spheres (or two Ship of Theseuses) are two separate objects even though they share all the same properties – but don’t share the same space-time. What are your thoughts?
Keith Wiley: This is very close to worm theory. It distinguishes seemingly identical entities by considering their spacetime worms, which squiggle their way through different spacetime paths and are therefore not identical in the first place. They never were. The reason they appeared to be identical is that we only considered 3D space projection of their truly 4D spacetime structure. You can easily alias pairs of distinct higher-dimensional entities by looking only at their projections onto lower dimensions and thereby wrongly conclude that they are identical when, in fact, they never were to begin with in their true higher dimensional structure. For example, consider two volumes, a sphere and a cylinder. They are 3D. But project them onto a 2D plane (at the right angle) and you get two circles. You might wrongly conclude they are identical, but they weren’t to begin with! You simply ignored an entire dimension of their nature. That’s what the 4D spacetime worm says about the identity of physical objects.
However, once we dismiss any relevance or importance of physical traits anyway (because I reject body identity on the matter of personal identity, favoring psychological identity), then the 4D worm becomes more convoluted. The question then becomes, what sort of “time worm” describes psychological changes over time instead of physical, structure, and material changes over time? I think it’s as simple as: take an information pattern instantiated in a physical system (a brain), produce a second physical instantiation, and now readily conclude that the psychological temporal worm (just a temporal sequence of psychological states frankly) has diverged.
Adam Ford: Nice answer! – I’m certainly interested in hearing more about worm theory – I think this wikipedia source is about the same thing: https://en.wikipedia.org/wiki/Perdurantism
Do you have any personal writings I can point at in the text form of the interview?
Keith Wiley: Ah, I hadn’t heard that term before. Thanks for the reference. Well, I always refer to my book of course, and more recently Randal Koene and I published a paper in the Journal of Consciousness Studies this past March.
Adam Ford: David Pearce is skeptical that our we as in our subjects of experience are actually enduring metaphysical egos – he seems more of a stage theorist – that each moment of subjective experience is fleeting – only persisting through one cycle of quantum cohesion delimited by decoherence.
Keith Wiley: Hmmm, I see the distinction in the link to stage theorist you provided above, and I do not believe I am committed to a position on that question. I go both ways in my own writing, sometimes describing things as true 4D entities (I describe brains that way in my book) but also writing quite frequently in terms of “mind descendants of mind ancestors”. That phrasing admits that perhaps identity does not span time in a temporal worm, but rather that it consists of instantaneous time slices of momentary identity connected in a temporal sequence. Like I said, I am uncommitted on this distinction, at least for now.
Identity: Accidental properties vs Essential properties
Adam Ford: Is the sense of an enduring metaphysical ego really an ‘accidental property’ (based on our intuitions of self) rather than an ‘essential property’ of identity?
Keith Wiley: It is possible we don’t yet know what a mind is in sufficient detail to answer such a question. I confess to not being entirely sure what the question is asking. That said, it is possible that conscious and cognitively rich aliens have come up with a fairly different way of comprehending what their minds actually are, and consequently may also have rather bizarre notions of what personal identity is.
Note that in the video, I sometimes offer an answer to the question “Did we preserve the ship in this scenario?” and I sometimes don’t, simply asking the viewer “So did we preserve it or not? What do you think?” This is because I’m certainly not sure of all the answers to this question in all the myriad scenarios yet.
Adam Ford: This argument is criticized by some modern philosophers on the grounds that it allegedly derives a conclusion about what is true from a premise about what people know. What people know or believe about an entity, they argue, is not really a characteristic of that entity.
There may be a problem in that what is true about a phenomenon or object (like identity) shouldn’t be derived from how we label or what we know about it – the label or description isn’t a characteristic of the identity (map not the territory etc).
Keith Wiley: I would essentially agree that identity shouldn’t merely be a convention of how we arbitrarily label things (i.e., that labeling grants or determines identity), but rather the reverse, that we are likely to label things so as to indicate how we perceive their identity. The question is, does our perception of identity indicate truth, which we then label, or does our perception determine or choose identity, which we then label? I would like to think reality is more objective than that, that there at least some aspects of identity that aren’t merely our choices, but rather traits of the world that we discover, observe, and finally label.
A Taxonomy and Metaphysics of Mind-Uploading https://www.amazon.com/dp/0692279849
The Fallacy of Favouring Gradual Replacement Mind Uploading Over Scan-and-Copy https://arxiv.org/abs/1504.06320 Research Gate: https://www.researchgate.net/publication/299820458_The_Fallacy_of_Favouring_Gradual_Replacement_Mind_Uploading_Over_Scan-and-Copy
The Endurance/Perdurance Distinction By Neil Mckinnon http://www.tandfonline.com/doi/pdf/10.1080/713659467
Endurantism and Perdurantism for a discussion on 3 different ways on what these terms have been taken to mean : http://www.nikkeffingham.com/resources/Endurantism+and+Perdurantism.pdf
Perdure – remain in existence throughout a substantial period of time; persisting in virtue of having both temporal and spatial parts (alternatively the thesis that objects are four dimensional and have temporal parts)
Endure – being wholly present at all times at which it exists (endurance distinct from perducance in that endurance has strict identity and perdurance has a looser unity relation (genidentity))
Genidentity – is an existential relationship underlying the genesis of an object from one moment to the next.
Gunk – In mereology, an area of philosophical logic, the term gunk applies to any whole whose parts all have further proper parts. That is, a gunky object is not made of indivisible atoms or simples. Because parthood is transitive, any part of gunk is itself gunk.
Keith Wiley has a Ph.D. in Computer Science from the University of New Mexico and was one of the original members of MURG, the Mind Uploading Research Group, an online community dating to the mid-90s that discussed issues of consciousness with an aim toward mind-uploading. He has written multiple book chapters, peer-reviewed journal articles, and magazine articles, in addition to several essays on a broad array of topics, available on his website. Keith is also an avid rock-climber and a prolific classical piano composer.
Also see Jennifer Wang’s (Stanford University) video as she introduces us to the Ship of Theseus puzzle that has bedeviled philosophy since the ancient Greeks. She tells the Ship of Theseus story, and draws out the more general question behind it: what does it take for an object to persist over time? She then breaks this ancient problem down with modern clarity and rigor.