Could you ever know what it’s like to be someone else?
Inner lives are probably unreachable, but we should still reach
My podcast this week deals with a question I’ve been chewing on since I was a kid: Can you ever really know what it’s like to be another person?
We generally assume the answer is yes, and we commonly say things like, “I know exactly how you feel.” But how close do we actually get?
Let’s start by asking this question about non-humans. Consider a bat, flitting through caverns in pitch darkness, sending out high-pitched clicks and interpreting the echoes that bounce back. Bats construct their picture of the world entirely through echolocation. That’s how they know where the cave walls are, where the stalactites are, and how to snag an insect out of midair in complete darkness. How much can we understand about their internal experience?
This example was leveraged by philosopher Thomas Nagel in 1974 in an essay titled What Is It Like to Be a Bat? He argued that we could study a bat down to the last detail (its brain, its behavior, its evolutionary history), but we still wouldn’t have any idea what it’s like to be a bat. We wouldn’t know its experience, its inner world. The subjective experience of being a bat is closed to us.
Nagel picked a bat because its sensory world is so alien to ours that it throws our assumptions into stark relief. We can imagine ourselves behaving like bats (hanging upside down, eating insects, using sonar) but that’s not the same as being one. And this, Nagel argued, reveals something important: subjective experience can’t be fully accessed from the outside.
That idea might apply not just to animal consciousness, but to a closer question for us: can we ever really know what it’s like to be another person?
When we’re kids, we assume everyone’s minds are just like ours. But as we age, we begin to understand that people can be wildly different from one another on the inside. Not just in terms of beliefs or preferences, but instead the deeper architecture of how we process the world.
Take synesthesia, in which a fraction of the population has cross-sensory experiences — like letters triggering color experience, sounds inducing visual shapes, or tastes provoking a feeling of touch. (For more on synesthesia, check out this episode, read my book on synesthesia, or take the tests yourself at my Synesthesia Battery).
And that’s just one of many examples of internal differences. Here’s another: Imagine an ant crawling on a checkered tablecloth towards a jar of purple jelly. When picturing that, some people will see every detail in high resolution, like a vivid inner movie (this is called hyperphantasia), while others will “see” nothing at all (aphantasia). (For more, listen to this episode or see our paper on measuring the phantasia spectrum in the brain scanner.)
Or consider word aversion, in which some people hear words like moist or tissue or panties… and feel genuine, visceral discomfort — while to most people the words are nothing but vocabulary. (For more on word aversion, check out this episode or our paper).
These kinds of individual differences are being increasingly discovered and studied in neuroscience, and what they surface is that our internal experiences are not universal. They vary wildly across the population.
This is where empathy enters the conversation.
Empathy is one of our greatest evolutionary tools. It allows us to simulate the emotions of others.
Or at least we think it does. The catch is that your brain is simulating your version of their world. It’s not necessarily what they’re actually feeling, and it may not even be close. Empathy isn’t a magical bridge connecting brains; all it can ever be is an internal simulation and a projection.
Just think about our reactions to fictional characters in books and movies. You know they’re not real—but when something bad happens to them, you feel it. You weep. You laugh. You tense up. You care. That’s your brain imposing emotions on a person who doesn’t exist.
Or take as another example the Boston Dynamics robots that people kick to demonstrate stability. Often people flinch when they see the robot get abused like this. They know it’s just a machine, but our brains fill in the blanks. We assume a mind and we feel the empathic sting. That tells us more about us than about the robot. It tells us that we always project our models, even when they are not accurate.
But we can still try
But empathy is still worth cultivating. Because although we can never truly know another person, we can stretch our imagination in their direction. And some tools help us do that better than others.
Literature, for example, is one of the most powerful empathy technologies we’ve ever invented. A 2013 study in Science found that people who read literary fiction—especially nuanced, character-driven stories—scored higher on tests of theory of mind, the ability to understand others’ beliefs and feelings. Reading literary fiction forces us to inhabit unfamiliar minds, decode subtle emotions, and simulate social complexity. Barack Obama said in an interview that reading fiction always helped him to imagine what other people were going through.
Virtual reality takes this further. In one Stanford study, participants put on VR headsets and experienced what it was like to become homeless. Viscerally. They watched their belongings being taken. They wandered without direction. And afterward, they showed more concern for homelessness—and were more likely to sign housing petitions. VR taps into your sensory perspective and temporarily rewires it.
The tools of fiction and VR don’t grant perfect access to other minds — but they train us to try. They’re empathy gyms. And in a world where understanding each other is harder than ever, that training matters.
So let’s return to the question we started with: Could you ever truly know what it’s like to be someone else?
I think the answer is no, at least not completely, and perhaps not even closely. The interior of another person is fundamentally private.
But that doesn’t mean the attempt is pointless. The act of trying, of reaching toward other minds with humility can be enough. Instead of saying “I know exactly how you feel,” we can say, “I’m here with you and I’m listening.” Even when we can’t step into someone’s skin, we can walk next to them.
But that’s not the end of the story. In next week’s Inner Cosmos podcast I’m going to dive into a deeper question: could future technology change our ability to empathize? Could we use brain-computer interfaces, neural implants, or nanorobots to directly experience someone else’s thoughts or memories? Could we synchronize brain activity and create a shared consciousness? Could we simulate not just behavior, but actual experience? Why or why not?
To find out more, please listen to Inner Cosmos on Apple, Spotify, iHeart, or wherever you get your podcasts.
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Let me know your thoughts on this week’s episode in the chat.
