When one normally thinks of reincarnation, one has in mind a caricature, the spirit of a Jane Doe coming to inhabit a frog, unbeknownst to anyone, except arguably Jane Doe herself. This, however, is an oversimplification. While reincarnation is often considered an idea lauded by Eastern mystics, modern-day science can be marshaled in to lend support to the idea of reincarnation—though in ways completely unexpected. For instance, one would usually hear the usual tripe: since matter and energy cannot be created or destroyed, one’s consciousness must live on after death. The argument that I want to consider is more intricate.
First, I want to begin from the finitude of brain states, an extension from the limits of phenomenal experience. I do not disagree that there is accompanying phenomenal experience for any interaction between an object and our senses. I do disagree that “what it is like” for me to smell roses is peculiar and markedly different from your experience of smelling a rose. I happen to think that our experiences are roughly equal. Whether or not you or I like the smell of roses involves more than just the phenomenal experience. In other words, there’s a lot of background noise that explains why you like the smell more than I do. Perhaps I associate the smell of roses with wakes and funerals rather than with candlelit dinners and weddings. The noise is not what I want to focus on.
Instead, I would like to focus on mental states themselves and argue that, though there are potentially innumerable brain states, they are finite. Even if we capture every brain state of every brained organism in the universe, and include also the correlate states of organisms that are conscious though lacking a brain, the total number of mental states do not stretch infinitely. Furthermore, the combinations of brain states, right down to the size and function of my brain or your brain, in particular, are finite. To put it another way, let us say that there is a limitation in the communication between one’s prefrontal cortex and cerebellum. This may result in autism or schizophrenia (Watson, 2014). With these particular disorders, there are a number of hallmark behavioral traits. This gives some credence to the idea that brain states are fundamentally finite and do not, as it were, stretch on forever.
Unfortunately, we are no longer so taken by behaviorists and know that human beings are a lot more than simply a finite set of behaviors. We have our preferences, things that we are repulsed by, our idiosyncrasies, and our personalities to speak of. Even then, I think that the combination of traits that make you you, no matter how multifarious, are finite. This implies that given a long enough time, some sentient being, whether Homo sapiens sapiens or something very similar to our own species, will come to believe in the same you that you believe constitutes you. This, to my mind, is how naturalism makes room for “reincarnation.”
Perhaps this will not happen in the next generation of life, or even in the next ten generations; but at some point, a sentient being will be born who believes, perhaps mistakenly, that s/he is me. In order to believe this, one need only believe that mental states, whether tied to a brain or to an intricate nervous system, are finite. If such states are finite, and the combination of such states and functions are finite, then there are only so many identities to go around. Given a long enough time, someone will come along and believe that they are exactly who Napoleon thought that he was.
The Reincarnationist’s Dilemma
This, in fact, falls on the horns of a dilemma that Buddhists face. Recall that Buddhists hold to the concept of anattā (no self). While I may have thrown around the word ‘identity’, this need not imply that I believe identity to be real and substantive. In fact, I think that it is entirely illusory and that if a person interacts with enough people, s/he will find that we have more in common than we would like to admit. Some of us have delusions of grandeur; we have god and savior complexes, see ourselves as fixers, and believe that there is no problem that we cannot solve. Others choose to mind their own business—to refrain from taking on a deep personal investment in the struggles that even loved ones go through—and instead choose to let the people around them work through their own problems. In one way or another, it is likely that my two brief sketches of identity resonate with readers. Either you are one who suffers from delusions of grandeur and base even your romantic relationships on a futile attempt to save everyone, or else you have no deep personal investment in the problems that even those closest to you have (this isn’t to say that you refuse to help when asked, but that you prefer to let people find their own way). If one of the two people that I have just described describes aspects of you, then you are further toward committing to the premise that mental states are finite and that, therefore, identities are limited.
Buddhists have long struggled to reconcile the idea of reincarnation with anattā, but a resolution isn’t difficult to come by. Before offering a solution, I defer to Wesley J. Wildman:
In fact, the anattā (no-substantive self) doctrine of most forms of Indian Buddhism means that there is no jīva (soul) that persists from life to life through death and reincarnation, as there is in most forms of Hinduism. The consequences for samsāra and nirvana of this view are complicated, and perhaps mind boggling, and Buddhists have spent enormous effort in debate over them, both with Hindus and among themselves. So it is not surprising that many Buddhists do not hesitate to picture life and death in rather Hindu terms, as re-enfleshment of an enduring soul, despite their characteristic no-self doctrine. Many Buddhist intellectuals will not do this, however, and their more subtle approach is not registered at all when the word reincarnation is used as the comparative category to comprehend both Hindu and Buddhist versions of the implications of samsāra for living beings. (Wildman, 2010, p. 133)
My resolution is that while there is no self—no concrete identity—what persists are the illusions of a self or an identity brought about by the limited combinations of mental states that humans experience. This is why so many of us come to have exactly the same ideas about ourselves, despite the fact that we are different people with vastly different past experiences. This is why mental and cognitive disorders feature an array of hallmark symptoms. To illustrate this even better, think of the way that genes encode phenotypic features. Straight thumbs, for instance, are expressed with a capital S in the representation of dominant or recessive traits, whereas hitchhiker thumbs are recessive alleles expressed with a lowercase s. This physical peculiarity, assuming that you have it, does not belong to you. There are other people who have hitchhiker thumb, and they have it because gene expression in their genomes have resulted in this phenotypic feature. Likewise, our mental states, the manner in which brain regions communicate with one another, and the way in which our particular neurons fire in our brains, create the same illusions of a static identity, packaged with a linear life narrative that we can literally draw a straight line through from our first memories in childhood through today.
There is no substantive self that persists—a soul, as it were. There is, however, a persistent illusion in all of us, and I do not put it past a being eons from now thinking that s/he is exactly who I think that I am. Furthermore, I do not discount the idea that s/he will feel, phenomenologically speaking, exactly as I do. There is this sense that I am. Whether or not identity is real, the illusion is powerful enough to lead me to believe that I am unique and that there will never be another exactly like me. This is folly. So while there is no substantive soul in either me or my cat, there are a number of mental states, resulting from brain and nerve interactions, that make both of us feel like we are unique individuals never to be replicated. I conclude that it is far likelier that since there are not infinite mental states to go around, there are not infinite illusions to go around, either. What we refer to as the soul or identity has its boundaries and limits. There will be another you, so in that sense even after death (should the universe persist) you will live again with no recollection of the you that you are right now.
This may seem particularly discomforting for some readers. Others may think that the idea is not developed enough. Now I’ll admit that the argument is very bare bones and could use more flesh. That, however, does not mean that the argument is unsound. I happen to be convinced, first and foremost, that mental states and what we call identities do not stretch to infinity, and that therefore there are only so many yous to go around. As such, you will live again or be reborn. This is how naturalism makes room for something as mystical as reincarnation. The lesson is that naturalists should shun the habit of dismissing an idea because it is religious or prima facie supernatural. There might be a kernel of truth to the idea of reincarnation. That remains to be seen, but my argument is certainly a good place to start.
Objections and Replies
It is standard procedure in philosophical practice to anticipate rebuttals. Perhaps my exploration of reincarnation within a naturalistic framework leans much too heavily on the nature aspect of who we are. Yes, if consciousness existed in a vacuum, and if the subject were sufficient to account for consciousness, then my argument would be quite forceful. A possible rebuttal takes the nurture angle, arguing that the subject is not sufficient to account for consciousness because the object is just as important, if not of greater importance, when attempting to explain consciousness.
If this is the case, then identity is not so elusive after all, and Buddhists and others who deny identity are wrong. How then do any of us answer the question: who are you? If you reply with “Sam,” then you have given us nothing but your name. As it turns out, your name is quite common. If your name gave us a full account of who you are, then anyone named Sam would also be you. Clearly, we both disagree with this conclusion, so your name is not enough. Exercises like this have been done ad nauseam, so I will spare you the runaround and just give you my answer: I am a particular experiencer. As are you.
Now, that requires some explaining, and this is where the object comes into focus. What makes me unique and other than you is that I have had an innumerable set of experiences that, when taken together, you have not had. Granted, it is very possible that we share at least one experience, even if we live a world apart. There are billions of people in China whom I have never met or interacted with, and I can say with all of the confidence in the world that they share experiences with me: being born, coming down with a cold, sweating, shivering, scrolling on a social media app, feeling a certain emotion like anger or sadness, and so on. I can also say that not one of them shares every single experience unique to me. If they are Chinese nationals, then they probably did not grow up in the Bronx. They do not identify as Puerto Rican or American. They do not check the Latino box when filling out a job application. These experiences, however, are overly simplistic.
Experiences are characterized by a given duration of time, an array of qualitative factors that produce in consciousness any number of qualia that go well beyond simply apprehending the color red or the smell of chocolate. It is also quite possible to have an experience too often and become numb to what makes it unique. One experience a lot of us have in common is that of going to a movie theater. There are certain sights, sounds, textures, and smells that are unique to the experience, but few of us can recall the buttery aroma of popcorn somehow mixing with the dull smell of a carpet that has been sullied and cleaned one too many times. There is the scent of leather seats (if you can count yourself fortunate enough to have the new reclining seats, that is) and other people. There is the texture of the seats, or of one’s footwear against the carpet, in addition to one’s eyes having to adjust in a very dim setting. So if any of my readers have ever pet a tiger in Thailand or jumped out of a plane to skydive, then they have a unique experience that, if described in full detail, does not align with anything that I have ever experienced.
The thing is that I, as a particular experiencer, have had a plethora of experiences in my life that are different from yours. The combination of these experiences is a huge part of what makes me me. The combination of your experiences plays a pivotal role in what makes you you. So it is not enough to say that mental states are inherently finite. While it may be the case that experiences are also finite, I need only convince you that the exact combination of my experiences and my distinctive mental states will never be replicated again and that therefore, naturalistic reincarnation is extremely improbable, and dare I say, impossible. The sheer improbability of something, however, does not make a thing impossible, so it is not enough to draw this conclusion and move on.
The improbability has to be crushingly discouraging to persuade you that it is simply more likely that naturalistic reincarnation is not the case. To show this, I am going to begin with a generous initial probability that someone else in the future will have any one of my experiences. I will list as many experiences as come to mind:
- Staying awake for 36 hours straight.
- Sleeping for 18 hours straight without waking up.
- Fasting for three days straight in a church in the Highbridge section of the Bronx.
- Eating Dole Whip at Disneyland about seven meters from the Indiana Jones attraction.
- Riding the Nitro at Six Flags in Jackson, New Jersey in the front row.
- Petting farm animals at Kira’s World Exotics Mini Zoo in Hatillo, Puerto Rico.
- Hearing the singing of coquis in Puerto Rico.
- Getting jumped on a school bus in the E. 161st Tunnel in the Bronx.
- Vomiting after too many drinks on the 6 train near Whitlock Avenue.
I can think of more experiences that are unique to me, but even when assigning a generous initial probability for any one of these events recurring, the likelihood of all of them recurring is extremely low. What’s more is that I have neglected a lot of variables. What was the weather like? What direction was the wind blowing, and at how many miles per hour? How old was I when all of these things happened? I only specified the event and its location because it is already very unlikely that you also vomited on the 6 train near Whitlock Avenue because you had one too many drinks. I did not mention that it was Cinco de Mayo in 2016 and after 8 PM. The more and more specific I get, the less likely it is that you will share this experience. If I were to include the people who were on the train and some of their reactions, which were surprisingly few given the amount of people on the train, the likelihood decreases even more.
In any case, if I were to assign an initial probably of 40% to each experience, we get the following: .40 * .40 * .40 * .40 * .40 * .40 * .40 * .40 * .40 = .000262144 or .026%. I listed just nine events in my life in scant detail and the probability of you experiencing all nine events, even starting with a very generous initial probability for each event of 40%, is very low (cf. Plantinga, 2000, p. 402). Now imagine if I were to be as detailed as possible about as many events as I can remember in my life; I am certain that this number will begin to approach at least one thousand. I can, for example, talk about my earliest memory: waking up in my crib, an infant, hungry and so delirious (probably having a hypnogogic hallucination) that I saw a bottle floating just out of my reach as a pendulum does, left and then right, left and then right; I reached for it and my hand went through it and I started wailing. My dad then gave me an actual bottle. Or I can talk about being seven or so years old and seeing a black and white striped insect fly into my room. It landed on my black toy chest and started to crawl like arthropods do. If I did, in fact, see a flying centipede or millipede that day, I saw a yet-to-be-discovered species, I might add. (I have scoured the Internet for this insect and have yet to come across anything like it.) This was before smartphones, so I could not snap a picture before it fluttered its wings and flew right back out. Hypothetically, though, if I did count a thousand experiences with an initial probability of 40%, we get .401,000—or about two thousand decimal places before you arrive at any nonzero integers. So you would get a percentage that is virtually zero.
Given how improbable it is that the combination of experiences that one has had will be replicated to the tee in a person that, more or less, has the same exact mental life that one does—i.e., is a one-to-one match to oneself with respect to nature—it is therefore extremely unlikely that another you or me will be born no matter how long the universe goes on. The universe can continue to exist for quadrillions of years, and I do not think that it is very probable that someone will have the combination of our respective experiences. I am a unique experiencer because of the combination of experiences that I have had, in addition to the admittedly finite mental states that occur in me. While those mental states very well do occur in other people, the probability that she and I have had the same exact set of experiences is extremely low, and it is that that makes us different. It is said that experiences mold us into who we are. Given my argument here, that is likely to be the case. If you are convinced that the unique set of experiences that you have had in your lifetime make you you, then I think you cannot be convinced of naturalistic reincarnation. What adds more force to this argument is that I have confined it to experiences I can remember, despite the fact that experiences I currently do not recall factor into the person that I am. There are so many subconscious joys and traumas that explain a great deal about us. This starts to venture into psychology, which for our current purposes is unnecessary.
Ultimately, reincarnation is incompatible with naturalism, not because it is too mystical, but because even if we were to imagine a version of reincarnation that is consistent with naturalism—i.e., steel man the notion of reincarnation—one’s full set of experiences is very unlikely to recur in the life of another person. Even twins, though sharing a lot of the same childhood experiences, end up having different experiences that, in turn, ensure that they are different from one another. As I have shown, it is extremely improbable, despite a generous initial probability, for another person to have just nine of the experiences that I have had, let alone a thousand or the actual and innumerable number of experiences that I have had in my life. Moreover, the longer one lives, the less likely it becomes that someone else will have one’s experiences. It is even more improbable still that someone in the far future will have the same exact set of experiences and have the same mental life as a centenarian in Japan (such as those of 119-year-old Tanaka Kane of Fukuoka City, who died in April). You are already at a disadvantage since it is impossible for you to be born in 1903, at the time that she was born, and to the same parents. It is virtually guaranteed that your set of experiences will differ from hers. Therein lies identity: you are a particular experiencer with a unique set of experiences. As Dave Chappelle said when remembering his late friend Daphne Dorman: “I am someone having a human experience.” At bottom, this is who we all are, but as with most philosophical topics, the Devil is in the details, specifically within the details of our distinct set of experiences.
Plantinga, Alvin. (2000). Warranted Christian Belief. Oxford, UK: Oxford University Press.
Watson, Thomas, Becker, Nadine, Apps, Richard, and Matthew W. Jones. (2014). “Back to Front: Cerebellar Connections and Interactions with the Prefrontal Cortex.” Frontiers in System Neuroscience, Vol. 8, No. 4 (February 4).
Wildman, Wesley J. (2010). Religious Philosophy as Multidisciplinary Comparative Inquiry: Envisioning a Future For The Philosophy of Religion. Albany, NY: State University of New York Press.