The rule for all of us is perfectly simple. Do not waste time bothering whether you “love” your neighbour; act as if you did. As soon as we do this we find one of the great secrets. When you are behaving as if you loved someone, you will presently come to love him.

~ C.S Lewis, Charity, Mere Christianity

One interesting question is: What is the self? By that, we mean identity: what defines who you are. This question has interesting consequences depending on which model of identity you adopt. So, what models exist?

1. Identity as the Body

This is the first basic definition we might come up with: in this model, what makes you you is your body. In other words, person \(P_1\) at time \(t_1\) is identical to person \(P_2\) at time \(t_2\) if the body of \(P_1\) at \(t_1\) is the same as the body of \(P_2\) at \(t_2\).

• A superficial problem with this definition is that our bodies change constantly: cells die and are replaced, our hair turns gray, we go bald, we get wrinkles, etc.
• Perhaps we could define the body in a way that excludes such minor changes.
• A more serious issue arises with brain transplants. Suppose we switched the brains of two people. We would not say that your current body with someone else’s brain is still you. Instead, we would say that you are wherever your brain has been transplanted.
• Thus, this definition fails.

2. Identity as the Brain

Building on the previous point, we might say that identity is defined by the brain. That is, \(P_1\) at \(t_1\) is identical to \(P_2\) at \(t_2\) if the brain of \(P_1\) at \(t_1\) is the same as the brain of \(P_2\) at \(t_2\).

• Again, we face the superficial problem that our brains change over time: cells die, connections change, but let’s set that aside.
• The deeper problem is this: what if we copy your brain molecule for molecule, atom for atom? We build an exact replica of your brain and then copy all your brain signals into it. Functionally and physically, it is now identical to your original brain. But which one is you? Are you in the original brain or the copied one?
• Most people would say that the copied brain is not you, and that you still reside in the original. So, this definition also has serious flaws.

3. Identity as Psychological Continuity

What if we define identity not in terms of physical characteristics, but in terms of psychological continuity, i.e. a continuity in thoughts, beliefs, and mental states over time? In this case, \(P_1\) at \(t_1\) is identical to \(P_2\) at \(t_2\) if there is a continuous chain of psychological states from \(P_1\) to \(P_2\).

• As before, we encounter the problem that our psychological traits change drastically over a lifetime. Our desires, beliefs, morals, and even memories evolve or disappear.
• But again, perhaps we can assume that some core continuity remains.
• The deeper problem can be illustrated with teleportation: imagine a future where we’ve developed teleportation technology. Your body is scanned, atom by atom, destroyed, and reassembled elsewhere in identical form. Psychologically, the copy feels and thinks exactly like the original. According to this model, there is psychological continuity, so identity should persist. But intuitively, many feel the original has died, and the copy is just that: a copy.
• See Parfit’s Teleportation Paradox for more on this.
• Another example is someone with advanced dementia. Despite a total loss of psychological continuity, we often still regard them as the same person. This raises doubts about continuity as the defining factor of identity.

4. Identity as Consciousness

Another model of identity is based on consciousness: what makes you you is the unique way it feels to be you. That is, \(P_1\) at \(t_1\) is identical to \(P_2\) at \(t_2\) if the conscious experience (what it’s like to be) at both times is the same.

I tend to favor this fourth definition. Why?

One empirical reason comes from cases of split-brain patients. In rare, extreme cases (e.g., due to epilepsy), the connection between the brain’s hemispheres is severed. The result seems to be two separate centers of consciousness within one body. Consciousness, in other words, appears divisible. Similarly, if we connected two brains with a high-bandwidth interface, it’s plausible we could merge two consciousnesses into one.

In either case, splitting or merging, I would argue that a new consciousness emerges, with a fundamentally different experience of being. That means it is not you. (See Sam Harris’s account in Waking Up for more.)

However, there’s a problem with this model too: conscious experience is constantly shifting. How it feels to be you now is different from how it feels after a meal, or when waking up, or when falling asleep.

So what this model suggests is that there is no stable, continuous self. The “self” is always changing. Every shift in experience gives rise to a new self. There is no enduring identity.

Moral Implications

This fourth definition has fascinating moral implications.

If there is no continuous self, then the affection or concern we feel for our future self should be no stronger than the concern we feel for others. It’s plausible that the conscious experience of a 20-year-old man is closer to that of another 20-year-old than to his future 80-year-old self.

In this sense, you are more closely “your classmates” than “your older self.”

This undermines egoistic claims that we should prioritize our own future over others. If there is no continuous self, then stealing or hoarding money for your future self is no more justified than doing so for someone else. You should, by this logic, be equally willing to steal or save for your peers as for “yourself,” because your future self isn’t really you in any meaningful sense.

If the self doesn’t exist as a continuous, unified entity, then it cannot be treated with privilege.

Think of a country where people were admired for running away in battle, or where a man felt proud of double-crossing all the people who had been kindest to him. You might just as well try to imagine a country where two and two made five. Men have differed as regards what people you ought to be unselfish to—whether it was only your own family, or your fellow countrymen, or everyone. But they have always agreed that you ought not to put yourself first. Selfishness has never been admire.

~ C.S Lewis, The Law Of Human Nature, Mere Christianity

It follows a simple argument about what I think is a good idea to value (I’m deliberately avoiding the words should or ought):

1. From Heidegger, we learn that all purpose and meaning depend on Dasein: that is, our lived experience as human beings in the world.
2. From Sartre and Heidegger, we learn that Dasein expresses itself through authenticity: the degree to which a person’s actions align with their values and desires, despite external pressures.
3. I also believe in long-range voluntary control: the idea that we can shape our beliefs by deliberately exposing ourselves to certain ideas or values over a long period of time.
4. From the Stoic principle of control, we learn that the only thing truly in our control is how we respond to situations, that is our character or virtue. Everything else, health, wealth, reputation, is subject to luck and external forces.
5. From these points, the following conclusions emerge:
   • From (1), value is not objective but grounded in lived, subjective experience.
   • From (2), our values are made real through authenticity, by living in alignment with them.
   • From (3), some values can be intentionally chosen through long-term engagement.
   • From (4), virtue is the only value that lies fully within our control.
6. Therefore, if I want to live the best possible life, not one based on chance or unstable externals, I should value something I can reliably attain. Since virtue is the only thing entirely in my control (per (4)), it becomes the most stable foundation for living well. By choosing (per (1) and (3)) to value virtue, I maximize my chances of fulfillment and stability. This is expressed through authenticity: by living and embodying this value openly and without hiding (per (2)).

In light of recent articles — The Eiffel Tower is NOT in Paris! and Philosophical Ramblings #06: Heidegger, Beliefs and Choosing One’s Values — I want to add an addendum to What is a person? Or when is a person? and Killing Dream People!.

In the former article, I proposed a definition of personhood i.e. being a moral agent, where “personhood” or “moral agent” is shorthand for “something deserving moral consideration”, as the capability to deploy human consciousness. In the latter article, I critiqued alternative definitions of personhood and what it means to deserve moral consideration.

However, I now have two issues with my earlier understanding. The first is that I did not adequately engage with a rival theory proposed in All Animals Are Equal, which argues that something deserves moral consideration if it has the capacity for suffering. The second is my use of the qualifier human in the definition of consciousness, which I did not justify sufficiently.

Let’s start with the first point. I don’t believe that the mere capacity for suffering can serve as a solid criterion for personhood. This is because the things involved, pain and suffering, are themselves morally neutral. What do I mean by this?

A knife isn’t inherently morally bad. Its “badness” depends on how it’s used, for example to harm someone or to slice tomatoes. Similarly, it would be strange to say that sleep is intrinsically good or bad. Sleep itself doesn’t contain moral qualities. Of course, I can talk about “bad sleep”, maybe I didn’t sleep well, slept too long and feel groggy, or kept waking up, but this is not because sleep itself is bad. It’s because of how I, as a subject, experienced that sleep. I judge the experience based on how it feels to me.

The same goes for involuntary actions like sneezing or reflexes. If I sneeze and get into a car accident because of it, I might call that sneeze “bad”, but what I actually mean is that the consequences of that specific sneeze were bad for me. The act of sneezing, in general, isn’t bad or good.

Pain works the same way. When I go to the dentist and they drill into my tooth, I feel pain, but the act of drilling isn’t bad, nor is the pain itself inherently bad. Pain is just a physiological response. What matters is how I experience that pain, how it arises in my subjectivity. That’s what makes it bad.

So, I don’t think the capacity for suffering is a good definition. But if we modify it slightly to the capacity for experiencing suffering, it becomes much better. This aligns with the famous philosophical paper What Is It Like to Be a Bat?, which emphasizes the difference between a process happening and it being subjectively felt. The former is objective; the latter is phenomenal.

This brings us to the question of how this fits with my original definition of personhood as based on consciousness. For that, we need a working definition of consciousness. One I like is: Consciousness is having a subjective experience of being or consciousness is what it is like to be. Again, this is in line with the bat article.

When we compare this definition of consciousness with the modified definition of moral consideration as capacity for experiencing suffering, we find they converge. Both hinge on subjectivity and phenomenal experience, there must be a “someone” to whom things appear. If you can experience suffering, then there is a “you” who experiences it, a subject. And if there is subjectivity, there is consciousness. So I would now argue that these two definitions are essentially the same.

Now to the second issue, my use of the qualifier human in “human consciousness.” The key question is: why human consciousness and not other forms? This is a fair criticism.

My reasoning was that I arrived at the conclusion, personhood as the capacity to deploy human consciousness, by analyzing examples that only included humans. So it seemed natural to restrict the definition to humans. But upon reflection, I see that this is flawed. There’s no solid justification for limiting it to human consciousness. Other conscious beings (e.g., animals) should be included as well. So the “human” qualifier should be removed.

What does this mean practically? What implications does this have for how I treat animals?

It depends on whether animals are conscious or not, and this is a difficult question. The crux is that consciousness is entirely internal. I know I am conscious, but I cannot know whether someone else is conscious in the same way, because to know what it is like to be them, I’d have to be them. This problem applies to animals too. We don’t know whether there is something it is like to be a bat, i.e. whether bats have inner subjectivity.

(Programmers might think of this like trying to access a private attribute in another class: you simply can’t do it.)

So, how should we decide whether to treat a given being with moral consideration? The best we can do, in the absence of certainty, is to make an educated guess.

What would such an educated guess look like? It depends on our model of how consciousness arises.

If we believe consciousness emerges from a certain level of neural complexity, i.e. enough brain cells organized in a particular way, then we might conclude that insects are not conscious and thus don’t deserve moral consideration, whereas animals with more complex brains (like monkeys or dolphins) might qualify.

On the other hand, if we believe that consciousness can’t just emerge from complex matter, because how could something entirely subjective arise from something entirely objective?, then we might lean toward a theory like Panpsychism. Panpsychism argues that consciousness (or subjectivity) is a fundamental part of reality, like particles or fields in physics. Conscious humans are then just concentrated expressions of this underlying “subjectivity field.” This view also resonates with thinkers like Schopenhauer.

If you’re more aligned with the first position (consciousness as emergent from complexity), it might be safe to say insects aren’t conscious and thus don’t deserve moral consideration, whereas smarter animals pose a moral gray area. If you lean toward panpsychism, however, then you might believe that all animals are, to some extent, conscious and therefore all deserve some moral consideration.

Personally, I haven’t yet read enough about panpsychism to form a firm conclusion, but from what I’ve seen, I tend to lean in that direction as a model for how subjectivity arises.