What makes you, you?
That’s one of those big questions that’s so big it deserves all caps—a BIG question. It might even be a BIIIIG question.
You’re complex. You contain multitudes, as American poet Walt Whitman said. There are an infinite number of things that can have an impact on your identity. Your culture, language, family, geography, race, gender, education, income, travel experience—they can all play a role.
With so many factors, it’s no wonder that scientists, philosophers, sociologists, psychologists, and others have been debating questions of personal identity since before the written record. And with so many different perspectives, they’re not even close to agreeing on how identities are formed.
Here are a few of the big debates in different fields to give you a sense of what people are studying today.
One common way of describing yourself is through your ancestry. If someone asks who you are, you might tell them that you have Belgian heritage—or Mongolian, or Venezuelan, or Native American, or whatever the case may be.
But how much can you really know about your genetic past? New services like 23andme claim to test your DNA and tell you where your ancestors are from. But the science behind it is much more complicated.
On the one side, scientists claim that new technology breakthroughs allow us to use the DNA in ancient bones to learn about how different cultures were formed. The field is called paleogenomics. By using genetics—the study of your genes—scientists can say exactly where your ancestors came from, when different groups of humans moved from Africa to Europe, and more.
“Ancient DNA and the genome revolution,” one of these scientists wrote, “can now answer a previously unresolvable question about the deep past: the question of what happened.”
“There’s no particularly good reason to believe that the past was significantly simpler than the present, and archaeologists have come to believe that the more digging they do, the more complexity they uncover,” the story’s author wrote.
As a result, paleogenomics is a source of controversy. Whether it’s possible for your DNA to tell you that your great-great-great-great-grandmother was from Spain or West Africa or the Yucatan Peninsula—that’s still up for debate.
You ancestry is one thing. Living in a culture and speaking its language is another. That is clearly meaningful.
Try to imagine that you grew up among Brazil’s Pirahã people.
According to the German newspaper Der Spiegel, they are a small tribe of a few hundred, and they have a very special language. It doesn’t have a past tense. They barely have any words about time at all. There are no numbers. And they don’t use the subordinate clause, which means, “Instead of saying, ‘When I have finished eating, I would like to speak with you,’ the Pirahãs say, ‘I finish eating, I speak with you.'”
Now, here’s the tricky question: if your language doesn’t have numbers in it, would it be possible for you to understand what a number is? Could you ever learn algebra or dream of being a mathematician?
What makes you who you are has a lot to do with what you think. But languages like the Pirahã’s make many scientists believe that what you’re able to think is limited by your language.
In fact, one famous theory called the Sapir-Whorff Hypothesis says that your language determines what you can think. As Der Spiegel explains, the theory says “people are only capable of constructing thoughts for which they possess actual words.” Since the Pirahã don’t have words for numbers, “they can’t even begin to understand the concept of numbers and arithmetic”—not because they’re not smart enough, but because of their language.
But the Sapir-Whorff Hypothesis isn’t necessarily true. It’s another controversial topic that linguists and other scientists continue to debate.
There’s a more obvious thing that affects what you think, too: your brain. A very famous case makes that clear.
As Smithsonian explains, Phineas Gage was working on a railway when an explosion sent a long metal rod through his brain. But Gage didn’t die. In fact, it’s reported that he never even lost consciousness—he was awake when he went to the doctor.
But that doesn’t mean Gage wasn’t hurt. Aside from the inconvenient hole in his head, his personality changed completely. Here’s how Smithsonian explains it:
Gage’s initial survival would have ensured him a measure of celebrity, but his name was etched into history by observations made by John Martyn Harlow, the doctor who treated him for a few months afterward. Gage’s friends found him “no longer Gage,” Harlow wrote. The balance between his “intellectual faculties and animal propensities” seemed gone. He could not stick to plans, uttered “the grossest profanity” and showed “little deference for his fellows.”
Or did he?
Writing for the Guardian, Mo Costandi explained that Gage’s story has been wildly exaggerated. “Ultimately,” he wrote, “it is impossible to separate the facts of this extraordinary story from the fictions.”
The reason Gage’s story has become so popular is that scientists and writers are able to use it as evidence for many different competing theories. “Gage’s was the first – and arguably the most important – case to reveal that some faculties can be associated with specific regions of the brain,” Costandi wrote.
For instance, we do know, according to Costandi, that “complex functions such as decision-making and social cognition are largely dependent upon the frontal lobes”—the part of the brain behind your forehead. But a lot of the specifics about which parts of the brain do what are myths, half-tested theories, or exaggerations that scientists are still studying.
Cases like Gage’s bring up philosophical issues about personal identity as well. For instance: assume that it’s true that Gage’s personality completely changed after his accident. Is it correct to say that Gage after the accident is the same person he was before the accident?
That can seem like a silly question, but it’s one philosophers take very seriously—and one that has tremendous implications for ethical questions. Say Gage was mean to you before his accident. If he’s a different person afterward, can you still hold “him” accountable for his bad behavior?
One of the most famous philosophers asking these questions was Derek Parfit, a British thinker who died in 2017. Parfit famously made the argument that personal identity doesn’t actually matter.
To make his case, Parfit used a thought experiment about your brain being transplanted. The Stanford Encylopedia of Philosophy explains it like this:
Suppose both of my brain hemispheres are functional duplicates of the other, and that each of my other two triplet brothers has suffered irreversible brain damage. A brilliant neurosurgeon can transplant one of my brain hemispheres into each brother, and so each survivor (we will stipulate) will be fully psychologically continuous with me upon waking up. [That is, they wake up with all your memories and experiences, just as you would.] What has happened to me? […W]e are forced to say that, because both brothers are psychologically continuous with me, they are both me. But then […] both survivors would also have to be identical to each other, which seems obviously false…
Parfit argues cases like this show we shouldn’t care about personal identity. Instead, we should think about connectedness, which is a matter of degree. Here’s how he explains it in a famous paper from 1971:
On this way of thinking, the word “I” can be used to imply the greatest degree of psychological connectedness. When the connections are reduced, when there has been any marked change of character or style of life, or any marked loss of memory, [we] would say, “It was not I who did that, but an earlier self.” [We] could then describe in what ways, and in what degree, [we] are related to this earlier self.
Gage might say he feels very distant from who he was before the accident, and so not feel responsible for whatever actions that former self took. But that’s obviously a controversial idea—we certainly don’t recommend telling your teacher that it wasn’t you who forgot your homework, but an earlier self!
But as developments in genetics, neuroscience, and linguistics continue, their findings help each of those fields, and they may make philosophies like Parfit’s seem more natural. One thing we’re pretty certain of, though, is that these debates won’t be ending anytime soon.