Who Was Martin Guerre?

Martin Guerre was a peasant in 16th century France.  He left for the war, and was gone for many years—so long, in fact, that his family was certain he’d passed away.  Then, one summer evening, an exhausted man in tattered clothes stumbled into his dusty southern France village.  Guerre had returned!  His four sisters rejoiced, as did his wife Bertrande, who had remained faithful all these years.  The whole village welcomed the advent of its long-lost traveler.  The whole village, that is—except for one man.

Path Towards Town

Come home, Martin Guerre!

Pierre Guerre, Martin’s uncle, felt uneasy.  Sure, the newcomer looked like his nephew.  But his gait was just a little slower, or his mannerisms more emphatic, or his voice more husky.  Something was a little off.  Pierre brought up his suspicion to Bertrande; she, of course, responded with incredulity.  “Ten years have gone by!  Of course he’s changed a little bit.  We have no idea what he’s been through!”  For several years, though, Pierre remained unconvinced.  Just as he was beginning to question his own sanity, he met a travelling soldier who had fought in the same war as Martin, and, in fact, had fought alongside him.  Upon further questioning, Pierre learned that the real Martin Guerre had lost a leg in the war.  The current one was a fraud!

With his new evidence, a furious and vindicated Pierre, along with a few skeptical villagers, took Martin Guerre to trial in the nearby city of Toulouse.  Still, though, to most of the town, Pierre looked like a lunatic.  What did the opinion of one soldier matter?  It’s more likely that the soldier himself had mistaken Guerre’s identity, not an entire village.  Further, Guerre eloquently and effortlessly answered questions about his life before the war.  Finally, Bertrande stood by Guerre throughout the whole trial.  Shouldn’t she know best?  Guerre would certainly be acquitted.

That is, until a second newcomer climbed the Toulouse courthouse steps.  He claimed to be Martin Guerre.  He asked to see his family.  And he walked on a wooden leg.

Bertrande had been sure that, for the last three years, she had been living with her husband.  But upon seeing the new Martin Guerre, she testified with unequivocal certainty that this was the true Martin Guerre.  Her four sisters agreed, and so did the rest of the village.  Guerre’s impostor maintained his innocence, but he was sentenced to death.

The day of his execution, the false Guerre finally confessed.  His name was Arnaud du Tilh.  He came from a nearby town, and was once mistaken for his lookalike by two friends of Guerre’s.  He then saw an opportunity for impersonation, learned everything he could about the real Guerre, and approached Guerre’s village.  As he stood on the gallows, he apologized to Bertrande, and asked for her forgiveness.  He was hanged in front of Guerre’s house.

What defines identity?  Is it consensus?  If it weren’t for Pierre’s suspicion, Arnaud du Tilh would have been Martin Guerre.   If everyone believes it’s true, it’s true.  Right?  Well, our story certainly invalidates that theory.  Consensus establishes truth, but only until that truth becomes false.  We’re looking for an absolute here.  So what does define identity?

Appearance defines identity.  Sure, it was easy to mistake Arnaud for Guerre until Guerre arrived.  But when both stood side by side, the difference was clear, even for Bertrande, who until then had been the hardest to convince.  The senses solved the Martin Guerre case, and they could solve any other—if not by looks, then by the sound of one’s voice, or the touch of one’s skin.  But wait—as an identical twin, I know the senses to be a poor arbiter of identity.  Plenty of people mix up my brother and me, even if we’re standing side-by-side!  Conversely, what about an accident that leaves one disfigured, or unable to speak?  Sensory evaluations of people change, but their identities remain constant.  We need a better definition than this.

Personality defines identity.  Another way to put it might be that the brain defines identity.  My twin brother and I may look alike, but we act differently, and people can tell.  What’s more: it doesn’t matter who people think we are; we both know who we are.  I know that I’m Josh; it doesn’t matter if everyone thinks I look like Ben.  Similarly, Arnaud never was Martin Guerre, simply because he knew he wasn’t.  Our brains contain the entirety of our memories, our genetic tendencies toward behavior, our desires, our skills.  If identity’s not in the brain, where is it?  This definition has problems too, though.  What about an amnesic who doesn’t remember his own identity?  He’s still the same person, isn’t he?  Further: personality and one’s concept of the self is variable.  Drugs can certainly change personality, as can traumatic brain injury.  Just look at Phineas Gage, one of neuroscience’s most famous case studies.  After a six-foot rail shot through his prefrontal cortex, Gage changed from personable and friendly to hostile, impulsive and short-tempered.  As his wife said, “He wasn’t the same Gage.”  (3) Fine, maybe he wasn’t.  But does that mean that I’m not the same Diamond until after breakfast, since I’m cranky until I’ve had my morning coffee?  If personality defines identity, we’ve got a lot of gray area to consider.

Legacy defines identity?  A prominent (albeit somewhat fringe) group of historians known as the Anti-Stratfordians believes that Shakespeare didn’t actually author the plays we attribute to Shakespeare.  William Shakespeare of Stratford-upon-Avon was just a front to hide the true identity, or identities, of the authors.  Francis Bacon, Christopher Marlowe, and the 17th Earl of Oxford are among the many possible authorship candidates. (4)  My grandfather scoffed at this theory, not because it lacks evidence, but simply because it was trivial to him.  “The guy who wrote those plays that we attribute to Shakespeare?  That guy was Shakespeare. ” He took a practical stance on the question: identity refers less to the person himself, and more to the set of achievements and characteristics we ascribe to that person.  Martin Guerre was the man, married to Bertrande Guerre, who left for the war in 1548.  The man who returned in 1556? The man who followed several years later, with a wooden leg?  According to my grandfather’s definition, perhaps neither was Martin Guerre, since neither created his legacy.  Of course, this definition is even more nebulous than our previous ones.  I bring it up almost facetiously, just to demonstrate the elusiveness and perhaps the irrelevance of the whole identity question.

Nothing defines identity.  The truth is that identity, above all else, is a construct.  We associate our being with our looks, our personality, our accomplishments, and so on.  But these things change all the time—every day in fact!  As urban legend has it, it takes seven years for every cell in your body to be replaced (probably not completely true, but you get the point).  How can we claim a permanent identity, when most of the cells in our body are only a few years old?  Identity is a useful concept, but that’s all it is.  It’s difficult to ground in actual truth.

At the same time, though, there’s no need to be nihilistic.  Our concept of identity exists for a reason; let’s not be afraid to use it.  Next time you see a close friend or dear relative, don’t be afraid to hug them.  They’re almost certainly who you think they are.


  1. Martin Guerre Wikipedia page
  2. The Return of Martin Guerre
  3. Phineas Gage: Neuroscience’s Most Famous Patient
  4. Shakespeare authorship question

9 comments on “Who Was Martin Guerre?

  1. Ben says:

    Awesome article. Remember when people used to ask: “Do you ever wake up in the morning and forget which twin you are?” Haha.

    • Josh says:

      Yes, classic twin question.

      A related joke: “I was walking down the street last week…at least I think it was me…”

  2. Nancy Diamond says:

    Fabulous. I especially love the sentence “Arnaud never was Martin Guerre, simply because he knew he wasn’t.”

    But let’s clarify what your grandfather used to say about Shakespeare. He used to say “whoever wrote those plays is Shakespeare,” by which he meant that it does not matter who the actual flesh and blood man was — his biographical and demographic information is of no import. He did not care where Shakespeare was born or who his parents were. Because when we say “Shakespeare” what we mean by that label is the author of the plays, whoever he may have been.

    Similarly, Martin Guerre was Bertrand’s husband and the proprietor of his property and Pierre’s nephew. And as long as he functioned in that capacity, and played those roles, he continued to BE Martin Guerre. This is a functional view of identity. And it worked as long as Pierre accepted him in the role of nephew. A competing and, in this case, contradictory, definition of identity is one I will call “biological.” In the biological definition, what matters is who gave birth to Martin Guerre. Because it just so happens that the law recognizes this as the defining factor for purposes of inheritance law. So the circumstances of birth give rise to the legal definition of identity. The case against Arnaud started with his hubris. He was not content to step into the life Guerre vacated when he went to war; he also wanted Guerre’s inheritance. When the newly arrived “Martin Guerre” claimed Pierre’s land, that’s when Pierre questioned his authenticity.

    As for biological, legal, and functional definitions of identity, a great source of hypothetical scenarios comes from the legal and social treatment of non-traditional families. One’s adopted child is one’s true son or daughter, yes — but only after a formal adoption process has been completed. What is the identity of the father? Is it the person who acts like your father (raises you), making the biological father a mere sperm donor? Or is the biological father always the “real” father? With mothers, it gets even more complicated. Is the woman who gave birth to you your mother, even if she is a surrogate who was implanted with another woman’s egg? Or is it the woman whose genetic material you’re carrying? Or is it the woman who raised you? I would say the functional definition of parentage does not work well, because then aunts, uncles, grandparents, even mentors, could become parents, and that does not match our society’s view of what it means to be a parent.

  3. Richard says:

    The Problem of Personal Identity is touched upon here. As a species of identity, personal identity should be subject to whatever conceptual problems arise in the case of identity simpliciter. But some philosophers think that there are no problems for identity. Here’s David Lewis (one of the 20th century’s most influential metaphysicians) in his 1986 On the Plurality of Worlds:

    “Identity is utterly simple and unproblematic. Everything is identical to itself; nothing is ever identical to anything else except itself. There is never any problem about what makes something identical to itself; nothing can ever fail to be. And there is never any problem about what makes two things identical; two things never can be identical. There might be a problem about how to define identity to someone sufficiently lacking in conceptual resources — we note that it won’t suffice to teach him certain rules of inference — but since such unfortunates are rare, even among philosophers, we needn’t worry much if their condition is incurable. We do state plenty of genuine problems in terms of identity.” (192-193)

    What Lewis’s point is, is that, at most, there may be a problem about how we know, in specific in stances, that one thing is identical to another. Only if we challenge Lewis’s view can we say there is a problem of identity beyond that which arises for our ability to know certain things and instead claim that there is a problem with the nature of identity as it is in reality. Either way, if we say that Guerre is whoever has certain properties associated with Guerre, then unless that collection of properties is very extensive we’ll always run the risk of saying that there’s more than one such ‘Guerre’. In saying that Guerre is whoever has a certain biology and biological origin, we must be saying something more than that he is whoever has a body made of a particular collection of cells etc. Because time will replace those cells without, presumably, replacing Guerre. The structure of Guerre’s body and brain, rather than the exact bits of matter, might instead be posited as what defines him as himself. But structure is, by its very nature, multiply-realizable, i.e. it can be replicated in other bits of matter. But if this were done, would we want to say there was more than one Guerre? If the psychological emerges from the neurological, which I estimate it does, then the mind and memories of the replicated Guerre will be the same too. Furthermore, in the literature on these problems, one has so-called cases of ‘fission’ and ‘fusion’, where our definition of person allows one person to become split into two, or two fused into one. A Star Trek-like ‘teletransporter’ is commonly used in these thought experiments, to specify that the original Guerre would be vaporized. When another, entirely similar Guerre is produced with the same memories, biology etc. then we feel that this Guerre – he has just been teletransported. But if the machine accidentally makes two copies, we feel a little less secure.

    John Locke had a theory of personal identity according to which it was constituted by memory and psychology. His critic, Thomas Reid, said that this violated the requirement that identity be transitive (that if a=b and b=c, then a=c), because it might be that a young man remembers being a child and so is the same person as that child, but later, as an old man, although he remembers being that young man he no longer remembers being a child. So, by Locke’s criterion, the old man is not the same person as the child, which violates transitivity. For various reasons, that I will not got into here, the philosophical problems of identity remain, mostly, unsettled, though they are certainly much better understood than they used to be. The cartography is more detailed and sophisticated, as it were, though whether any true realm corresponds to the map is as yet contested.

    • Josh says:

      Interesting points. I agree that we should see if we can sort out identity as a whole before we seek to sort out personal identity.

      Lewis’s point does seem compelling. Things are those things; they are not other things. Are we done?

      I think this works best if said things are indivisible. One widget is one widget, of course. You mentioned fission and fusion, however. Is it still the same widget if it’s broken in half? What about once it’s put back together? I’m not sure where Lewis would stand here, but regardless of what he would say, I’m not sure we’ve reached any new understanding or made any progress. Perhaps the questions I’ve asked are undecidable or incoherent.

      However, if we can’t decide on identity, then surely we’re at a loss regarding personal identity. I think the points regarding fission and fusion are poignant, because, as we’ve mentioned, cells of the human body turn over quite frequently. I’m shedding skin cells as we speak, and I shed a few brain cells in my skateboarding/college drinking days. So, even though “fission of the widget” seems contrived, fission of the human is less so. We don’t even have to talk about reduplicative teletransporters.

      Theories on psychology and personality seem more promising. They might not suffice to give each person a unique identity in a general sense, but we might settle for a weaker version, in which each person has a unique personality. The Martin Guerre situation would pass this test.

      If someone had an irreversible brain injury, their personality would change. We can say this while remaining agnostic on whether or not their identity changed. Meanwhile, a Star Trek reduplicator could in theory produce two people with the same personality. However, again, we can allow this, so long as we don’t have to ask whether or not they have the same identity.

      Again, personality is easier to handle than identity. Identity itself, however, doesn’t actually seem too difficult (see Lewis) until we start introducing pathological scenarios: Martin Guerre, Star Trek, brain injury, etc.

      Then again, by introducing weird and variably contrived scenarios into our framework, we can turn almost every solid concept into an amorphous set of bad rules.

      I think the whole point I wanted to make in this article is that our concept of identity, while subject to problems, works most of the time. Perhaps we’d do best to not try digging any deeper.

      • Ben says:

        It seems like you’re opting to replace the relation “identity” on the set of people-times with a coarser equivalence relation, “personality”. I like this idea. The latter is less thorny to define and seems to suit us for most of our purposes. After all, until Where Am I becomes true, the latter might be not-strictly coarser.

        Of course, one consequence of the fact that it’s coarser is that if someone, upon sustaining a brain injury, developed a new personality, we’d be forced to concede also that they received a new identity.

        There are scope ambiguities in your sentences “each person has a unique personality”, etc. The words “unique” (or “the same”, or “different”) create terrible problems. I’d like to look into these some day. I see at least three readings:

        Each person has a unique personality.
        (1) For each person, there is only one personality that that person has. (One person can’t have two personalities.) Each person’s personality is unique in the set of personalities that that person has.
        (2) There exists a personality such that all people have that personality. (Everyone has the same personality). The personality that each person has is unique in the set of personalities that some (narrow scope) person has.
        (3) For each person, there is only one personality that that person has, and for each personality that some person has, there is only one person who has that personality. (No one personality is had by two people.) The person who has some particular (wide scope) personality is unique in the set of people who have that personality.

        More mathematically, the relation from people to personalities is (1) a function, (2) a constant function, (3) an injective function. The resulting equivalence relation on people is that given by taking the fibers of this map. Only (1) leads (in general) to an interesting equivalence relation. (In (2) we get the trivial relation; in (1) we get the equality relation.)

        I think it’s (1) that you meant. Is it?

      • Josh says:

        What I really meant was 1 person ←→ 1 personality. So, (3).

        If Star Trek duplicators are allowed, then I mean (1).

        Also note that, if personality change is allowed, such as in the case of Phineas Gage, then (1) is true across space but not time.

        Finally, I’m not making any claims about whether identity is a subset of personality, or vice versa. It’s conceivable that personality could change but identity would not. In fact a lot of people would probably say this is true of Phineas Gage. It depends on how you define identity, which we have deemed problematic.

    • Ben says:

      I agree with the things Josh has said. It seems to me that Lewis has effectively restated the definition of “identity”. “Everything is identical to itself; nothing is ever identical to anything else except itself.” This are true by definition, it seems. The hard part surely comes in when we have to decide what the “things” are. Are “Ben” and “an identical copy (not Josh!) of Ben which has been produced by a teleporter” the same thing, or different things? What exactly is Ben in the first place? Is he one thing, or multiple things? Are his brain/body and him the same thing, or different things?

      Neither is it true, I think, that these are merely empirical questions, as you (or perhaps Lewis) seem to suggest (e.g., “at most, there may be a problem about how we know, in specific instances, that one thing is identical to another”). These seem to me deeply conceptual questions. That is, I think that even if we don’t challenge Lewis’ view — which, again, I might just take to be a definition — the problems of identity we encounter will extend beyond the merely empirical.

      Of course, I think you too would admit so much, given your comments later. The questions you pose seem decidedly conceptual.

      We could contrast this with math, where typically the definitions of the concepts we’re interested in are sufficiently precise as to make the questions become once again “empirical” rather than conceptual. For example: On a smooth projective complex algebraic variety, do the filtrations on the cohomology given by the Hodge coniveau and geometric coniveau coincide? (This is the generalized Hodge conjecture.) This is a question about the identity of two things. Here, indeed, the (as it turns out, unfathomably) hard part is the work of figuring out whether the two concepts — whose definitions, again, we’ve precisely pinned down — happen to coincide. In the case of, say, Martin Guerre, the situation seems different.

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