Science can explain how we see, hear, and smell, and why we feel hunger. Increasingly, in the nearly 50 years since Thomas Nagel’s paper, “What is it like to be a bat?,” was published, science can even explain more complex aspects of human life, like fear, pain, and some emotions, by “reduc[ing]” them to physical elements like nerves in the eye, or chemicals in the brain. Even though it can be interesting and useful to describe human experiences that way, something gets lost in the process. When I’m in pain, I don’t feel nerves firing in some part of my body. I feel a sharp unpleasant sensation, or a dull ache, that demands my attention. How do we move from the scientific, physical description of pain to the way it feels to me? Or, more generally, what do we do about the gap between reality and the way we experience it?
The problem is essentially that physical events and conscious experiences are so different that it is very difficult to understand one as the other. We’re so used to having conscious experiences of life that it’s easy to forget two important things about them. For one thing, although they’re real to us, they aren’t the same as reality. We know, for example, that feeling a pain in your stomach doesn’t necessarily mean it’s your stomach that’s hurting— the pain could be coming from an organ in a very different part of your chest. Secondly, all of our experiences are determined, or framed, by our particular perspective, so that two people can have very different experiences of the same event.
To highlight the difficulty this creates, Nagel invites us to consider the experience of a creature that is very different from humans, but still has a conscious experience of its own: a bat. Physical facts about bats are easy for us to find out through science. We know, for example, that bats use a system of echolocation, where they shriek and use the way the sound echoes off of the objects around them to determine how far away the objects are, as well as their size, shape, movement, and texture. We can identify that the kind of information bats get from echolocation is similar to the information we get from our vision. None of this, however, tells us what it feels like to be a bat, and experience the world through echolocation. In fact, Nagel argues that there is nothing we can do that would let us understand the conscious experience of a bat. We could imagine behaving as a bat behaves, having webbed wings and poor vision, flying at night and sleeping upside down, but at best, that will only tell us what it would be like if our human mind was in a bat’s body, not what it is like for a bat to be a bat. We know that the bat is experiencing the same objective reality we are, and we can determine facts about it. However, even with those facts, we will never approach understanding the bat’s experience of that reality, because we can never get past the limitations of our own perspective.
This applies to our understanding of other human experiences as well, although it plays out differently. Using science, we can identify nerves firing in a bat, or in another person, that match the nerves that fire when we experience pain. And, unlike a bat, another person can also describe how the pain feels, so we can feel relatively certain that our experiences are similar. However, we will still never be able to imagine their pain without starting from our own experience of it. Putting ourselves in their shoes won’t tell us what their shoes feel like to them— we can never actually feel what they feel. This problem has real consequences. Faced with conflicts between a patient’s account of what they’re feeling, scientific evidence, and their own point of view, doctors often discount the patient’s experience and make incorrect assumptions about what they need. For example, doctors consistently underestimate the amount of painkillers needed by Black women because ingrained racism leads them to distrust the women’s descriptions of their experiences and fall back on stereotypes.
What does this mean for human understanding in general? Potentially, it means that there are some facts about other beings, like bats, that we’ll never be able to understand because of limits built in to our individual perspective, what Nagel calls “our nature.” And even with other humans, our imagination may not be as successful as we think at understanding the experiences of others. Like a frame we see the world through, the limits of our perspective define the boundaries of what we understand, leaving room for dangerous assumptions about how other people feel.
“What Is It like to Be a Bat?” was published in 1974 by Thomas Nagel in The Philosophical Review