This was a topic introduction I shared at an event called Ideas and Questions Cafe held in Tokyo. These events are intended to promote discussion and exchange of diverse perspectives among participants. They also typically introduce a Christian perspective which is nearly always novel for most participants. You can also view this content in Japanese here.
All of us here are human beings. And many of us would say that being human confers special rights, and has inherent value. But it’s not so easy to define what makes one human. The question we’re exploring tonight in short form, which people have considered for millennia, is “Are humans different from animals?” But I’d also add, “Are we different from (as of now, hypothetical) advanced human-like AI?” In other words, is there any practical and meaningful way to draw a line between a human being and a non-human?
There are a few ways to answer this question that jump out immediately. Let’s look at a couple of very intuitive criteria before ending with an interesting but less intuitive idea.
Criterion 1: Characteristics and Capabilities
In other words, things that a human can do that an animal (or advanced AI) cannot, or attributes a human has that a non-human doesn’t have. Let me just list off a few things that often come up:
- Physical characteristics (including genetic makeup)
- Reason
- Language
- Altruism
- Morality
- Consciousness
- Soul/spirit
Drawing the line between human and non-human based on something we can do or some attribute we have is attractive because it seems objective and positive. Critics note, however, that firstly this raises serious questions about how the disabled or otherwise impaired are treated. If being human is defined by our abilities, what about when someone lacks those abilities? And secondly, what if these abilities are not binary—things you can or can’t do—and instead are on a continuum, where it’s just a question of degree? How do we draw the line then?
There’s a funny story which illustrates this. The ancient Greek philosopher Plato had defined a human as a “two-footed, featherless animal”. A rival philosopher named Diogenes sees people praise this definition but he feels it’s not that great. So (according to the story) he takes a chicken, plucks its feathers out, and goes to Plato’s school. Then in the school he holds out the chicken and says, “Look, a man!” And apparently the result of this incident was that Plato added to his definition. “A two-footed, featherless animal… with broad, flat nails.”
The point is that any definition of humanity that includes some kind of characteristic or capability has to deal with the dividing line between human and non-human being arbitrary. Because first, as the story illustrates, a line that’s basically arbitrary is not intellectually satisfying. And second, an arbitrary line is subject to being redefined in ways that could result in others being treated as subhuman.
Let’s look at the next very intuitive way to draw the line:
Criterion 2: Origins and Lineage
Up until relatively recently in human history, this was perhaps the most straightforward way to define a human. Does it descend from a human? If so, it’s human. That immediately causes one to wonder if there was a first human ancestor. So in addition to biological lineage, virtually all cultures have a mythical story of human origins in part to answer the question of where the first humans came from.
In the present day, based on the criterion of biological lineage, one would conclude that humans are not significantly different from other animals. The current understanding of available scientific evidence also flies in the face of the mythical origin stories, indicating instead that the gradually compounding effects of natural processes over a long period of time account for how humans came to exist.
Evaluating human and non-human based on lineage therefore, is both attractive and not attractive. Attractive, because it seems objective and less arbitrary than choosing specific traits to define humanity. Unattractive, because the conclusion that humans are more or less equivalent to animals opens up a host of important questions. Should human life and animal life (or for that matter, plant life, fungal life, or bacterial life) be treated equally? Should we all have the same legal rights? Furthermore, some religious traditions interpret their stories of human origins along non-material lines. So in other words these immaterial origin stories, which touch on immaterial things like spirits, are able to be read in parallel with biological, material origin stories. Trying to judge what is or isn’t human based on something basically imperceptible is not practically useful.
So let me discuss a final way to draw the human/non-human line which, though less intuitive, may be an interesting alternative:
Criterion 3: External Designation
Instead of drawing a line between human and non-human (or arguing there is no line) based on characteristics, capabilities, or origins, what if being human is externally defined? Take, for example, a boundary stone. On an atomic level there is nothing significantly different about these stones than others around them. They all come from the earth’s crust. Yet because at some point a human being designated the stone as being not just any rock, but a boundary-marking stone, it gained a new significance.
Or imagine someone adopting a pet. On a biological level, there is nothing remarkably different between a fish in your house and a fish at the pet store. They’ve been born in the same way. But because of the action of choosing the fish and designating it as your pet, the pet fish has gained a new identity.
One proponent of the idea that humanity is a status given by external designation is the Hebrew Bible, used in Judaism and Christianity. In the opening lines of the book of Genesis, we read the following:
Then God said, “Let us make humankind in our image, after our likeness, so they may rule over the fish of the sea and the birds of the air, over the cattle, and over all the earth, and over all the creatures that move on the earth.” …God blessed them and said to them, “Be fruitful and multiply! Fill the earth and subdue it!” (Genesis 1:26, 28)
The phrase “image and likeness” is an important Ancient Near East term. In this context it implies not only that humankind is similar to their divine Maker, but also 1) that humanity would hold an elevated role in the world as God’s representatives, 2) that they would therefore have commensurate responsibilities to God, and 3) that they would enjoy a special and close relationship with God. Then instead of their special characteristics or lineage defining their identity, according to this idea, God provides them with unique capabilities and an ongoing lineage so that they can carry out their identity. This perspective not only draws a line between human and non-human, but also proposes a vision for what humanity ought to be.
Christianity then takes this a step further by arguing that though humanity has actually failed to live up to their elevated identity, God has graciously begun re-making individual human beings in the image of Jesus Christ to be a kind of artistic masterwork.
Of course, the obvious issue with defining humanity based on an external designation is that it assumes the existence of an External Designator, and it’s unclear how we would verify the existence of such a being. But what do you think? We’ll now enter our time of discussion.
Ben Shimomura 