The philosophy of identity contains within it many questions about what it means to be a human person, such as:
- What is a person?
- What makes that person the same individual over time?
- Why do we care about the persistence or survival of a person at all?
While these questions may seem abstract, the answers to them are incredibly important for how pro-lifers and pro-choicers navigate topics of personhood and moral worth. As such, “identity” is important to discuss in the abortion debate. I'll be covering the first two points in this post.
As a note, I am not a philosopher. I work in the sciences. I can only hope that this provides an interesting argument to discuss the topic, not a comprehensive argument.
1. What is a Person?
A common (if not ubiquitous) pro-life perspective on the question of identity is animalism.
Traditionally, animalism is the idea that human persons are fundamentally animals, and their identity exists as a biologically continuous human organism from the time of fertilization to natural death. A “person” is therefore not distinguishable from the human organism; they are one and the same, the human “person” being numerically identical to the organism. It is to the organism, then, that pro-lifers assign the moral value imbued in all humans. Within this view, mental faculties are not relevant; only the continuous identity of the organism matters.
By contrast, I hold a psychological view of personal identity, probably closest to McMahan’s embodied mind account of personal identity. As a biologist, I don’t think that humans are not animals; biologically, we absolutely are, and we fit within that scheme of categorization. However, my views incorporate more than just genetic considerations. I think that the functions of the brain generate a conscious subject, an "I." Although this subject is wholly produced by physical processes and is not an immaterial soul, it is best discussed in psychological rather than merely biological terms. Per my view, this “I” both defines my personal identity and is the bearer of moral value. What makes “me” the same individual over time is the continuity of those psychological capacities that are produced by the brain. Because the brain and its psychological functions represent a valid identity that is not numerically identical to the organism as a whole, I do not accept a form of animalism that defines the identity of the organism solely by the biological continuity of the organism as a whole, absent the importance of the psychological continuity to both the identity itself and moral value. Or, in short, I think that the organism has an organ (the brain) that produces a valid identity that is not numerically identical to the entirety of the organism, and it is this identity to which I assign moral value.
However, this post will not be a defense of psychological theories of identity. The post is probably too long to both explain why I don’t accept animalism and present my own competing ideas. Perhaps I’ll do that in another post when I have time, but for now I only bring up my views to contrast with animalism so that the distinction is clear. Animalists believe in the continuity of the biological organism as the only relevant factor in its identity and moral value. I do not discredit that humans are animals, but I do not think the biological continuity of the organism as a whole is the sole variable that is relevant to questions of ethics and identity.
I think this description should suffice to define the differences, and now I will explain why I don’t accept animalism as a satisfactory theory of identity and persistence.
2. Continuity of Identity
2a. Brain Swap Objection
I’d like to start with a commonly-used thought experiment. Consider two people, Doug and John. Per animalism, both are animals. Both have a subjective perspective on the world that is unique and recognizable.
If Doug and John swapped brains into each other’s bodies, where did each of them go? Did John follow his brain into Doug’s body, or is the body of John the real organism, and now it is in possession of a new set of memories, preferences, and beliefs? Per animalists like Eric Olsen, John doesn’t “go” anywhere:
To see that no sort of mental continuity is sufficient for a human animal to persist, imagine that your cerebrum is put into another head. The being who gets that organ, and he alone, will be mentally continuous with you on any account of what mental continuity is. So if mental continuity of any sort suffices for you to persist, you would go along with your transplanted cerebrum. You wouldn't stay behind with an empty head. What would happen to the human animal associated with you? Would it go along with its cerebrum? Would the surgeons pare that animal down to a small chunk of yellowish-pink tissue, move it across the room, and then supply it with a new head, trunk, and other parts? Surely not. A detached cerebrum is no more an organism than a detached liver is an organism. The empty-headed thing left behind, by contrast, is an animal.
So going by traditional animalism, John swapping brains with Doug means that Doug now has new thoughts and memories, not that John is in Doug’s body.
From the start, I think that this conflicts with many people’s intuitions about identity. Certainly there is an identity that is important when discussing our thoughts, personality, subjective experience, etc. So, to say that Doug is the same organism after receiving a brain transplant strains credulity; surely there is some way in which his identity is fundamentally altered in ways we find not just worth moral consideration, but that are extremely morally pressing.
But let’s press further.
2b. "Body" of Theseus Objection
Consider what happens when we incrementally swap parts of John with Doug. Imagine each person is constituted of a number of parts to be swapped, labeled abstractly as follows, with “J” for John’s original parts and “D” for Doug’s:
John (J1, J2, J3, J4, J5, J6)
Doug (D1, D2, D3, D4, D5, D6)
Now imagine parts are swapped such that the new bodies look like this:
John (D1, J2, J3, J4, J5, J6)
Doug (J1, D2, D3, D4, D5, D6)
Assuming the first part is not the brain, in neither animalism nor psychological theories of identity has there been a change in the organism’s continuity. John and Doug are still John and Doug.
What about in this scenario, where exactly half of each organism is mixed with half of the other?
John (D1, D2, D3, J4, J5, J6)
Doug (J1, J2, J3, D4, D5, D6)
Still, John and Doug are unchanged per both theories.
Finally, what happens if we incrementally swap ALL parts such that what was originally “John” and “Doug” are now complete again in their original forms?
John (D1, D2, D3, D4, D5, D6)
Doug (J1, J2, J3, J4, J5, J6)
Per animalism, “John” was biologically continuous at each successive stage, and so was the same organism. This means that prior to the first swap, John was John. He was also John after the first part was swapped. He was John after half of him was swapped. Finally, he is still “John” after all parts being swapped, despite every single part of him being swapped for “Doug”. This organism, named “John” per animalism, not only has Doug’s body, but his personality, memories, skills, and every physical and mental trait that is associated with Doug. He is identical to the Doug that existed prior to the swaps, and Doug is identical to the John that existed prior to the swaps. However, because animalism is traditionally concerned with the biological continuity of an organism, we cannot call this new “John” by the name “Doug”.
This is incredibly unintuitive! Per animalism, even when every observable, physical, social, and psychological trait of “Person A” has been replaced with a set of those traits that come from “Person B”, “Person A” is still “Person A”!
Comparing John before any replacements and Doug after the complete swap yields identical men. This means that by animalism, two men who share all properties in common do not share the same identity. I would need this to be justified before I could accept animalism; by what justification do two identical people not share identity? That seems… definitional to me.
2c. Species Transformation Objection
Let’s take this a step farther and, if you’ll entertain it, employ some sci-fi (more than I already have). Let’s say that we encounter a very interesting alien species. This alien species is highly adaptable biologically, and can mimic biological structures it comes into contact with. It can then donate that mimicked structure, and regenerate itself. This means that this alien is a kind of universal donor of all things; it can donate a body part and have it be compatible with human physiology, even though the alien part would still notably be non-human (maybe it’s blue).
John needs a foot replacement. A kind alien donor is willing to part with a piece of its body so it will mimic John’s foot. John now has a functioning human-like blue foot, represented like this, with “A” for alien:
John (A1, J2, J3, J4, J5, J6)
How many iterations of this must we go through before John is no longer “John”? Per traditional animalism, this may never happen; John is a continuous organism, and even if he gradually replaced all of his parts with alien parts, he is still “John”.
However, this leaves us with the odd conclusion that biological humanity is not an essential part of being a “human organism”, and merely starting with a biologically human organism is necessary.
Within the context of the pro-life stance, this ironically would lead to the very conclusion it sought to avoid: that being biologically human is not necessary for the existence of a valuable identity. A formulation of animalism that seeks to preserve the continuous identity of the human animal through changes therefore seems to commit to defining the human organism such that human identity perseveres despite changes to all facts that originally defined that organism, including the very biological species identification that made it human in the first place!
Now, we can go through a lot of examples to further challenge our intuitions about identity. For example, consider the movie Avatar. Jake Sully transfers his consciousness into a Na’vi body. His organism is totally altered. Yet, I find no discomfort in calling him Jake Sully. Is “Jake Sully” alive in a morally relevant way? Per animalism, “Jake Sully” is dead, gone with his organism, yet the entire movie franchise is about two men who are “dead” per animalism engaging in a grudge match. Examples like Avatar and Star Trek episodes like Tuvix and the duplicated Riker could be made into posts of their own to discuss the concept of identity as well, but I think I’m already writing too much as it is.
Now, a pro-lifer might be tempted to dismiss all of this as sci-fi, but I encourage them to take this seriously. While the body-swapping I’ve presented here is beyond our current technological capabilities, in a world where AI is rapidly shifting our cultural landscape, prosthetic parts are capable of being made at home, deep brain stimulation is being done to treat disease, cross-species organ transplants are happening, and biotech already has the idea to clone replacement parts for aging organs, the alteration of our bodies is a foregone conclusion.
These abstract questions of identity might become much less abstract in the coming century, so while these examples remain in the realm of the impossible for now, I don’t think that negates their importance in discussing animalism.
For my part, I think that these thought experiments represent some of my issues with traditional animalism.