Ethics Explainer: What is it like to be a bat?

“What is it like to be a bat?” is the intriguing question philosopher Thomas Nagel asks in his 1974 article, first published in The Philosophical Review.

Nagel’s argument goes something like this:

“We can imagine what it might be like to be nocturnal, to have webbing on our arms, to be able to fly, to have poor vision and perceive the world through high frequency sound signals, and to spend our time hanging upside down.”

“But even if we can imagine all of these things, it only tells us what it is like for me to be a bat, or for me to behave as a bat behaves. It does not tell us what it is like for a bat to be a bat.”

More than meets the eye

Is Nagel correct?

Nagel is pointing out that there is a subjective character of conscious experience that is not captured by physical descriptions of the brain or observable behaviours. He is taking issue with the reductive materialist or physicalist account that denies the so called gap between ‘mind’ and brain in the mind-body problem.

The mind-body problem comes about because we often subjectively feel as though our mind, with which we often identify the most, is somehow so much more than just our physical brain. Our mind sometimes also feels separable (even if not detached) from our body!

For example, we may forget that we are sitting on a bus, riding to work, and instead be transported back to an earlier time through the use of our memory. There is also the sense that my experiences are truly unique to me, and no one else can understand them in quite the same way.

The materialist denies the gap between mind and brain by arguing that the mind and consciousness is explainable entirely by physical processes. This position they defend is known as monism, and stands in contrast to dualism.

Note that René Descartes was a Dualist, due to his account of mind and body as two different substances. He equated the mind with the soul – an immaterial substance.

Mind over matter?

While Nagel is not committed to dualism, he claims that physicalism, if it is to be convincing, needs to account for both objective and subjective experience. Both are required to understand the mind-body problem. He contends, “Without consciousness the mind-body problem would be much less interesting. With consciousness it seems hopeless’”!

Nagel doesn’t think we can easily explain consciousness by simply describing a person or animal’s experience or set of behaviours.

This raises the troubling question: if I cannot embody a particular perspective, for instance, I cannot actually be anyone other than myself, then how can I truly understand it?

How can I ever know what it is like to be a bat, a dog, a cat, a horse, or even another person? Can I only ever truly understand what it is like to be me?

Nagel highlights the fact that there’s something mysterious about consciousness that cannot simply be explained away.

Nagel’s argument has been met with criticism. Daniel Dennett is one such critic, even while acknowledging this paper as “The most widely cited and influential thought experiment about consciousness”.

Dennett denies Nagel’s claim that the bat’s consciousness is inaccessible. He says the most important features of a bat’s consciousness would be accessible in some way to third person (that is, ‘objective’ or empirical) observation. In this way, information about what it is like to be a bat could be gleaned using scientific experiments.


Does it feel the same to you?

Yet this thought experiment still captures the imagination and plays on our fears of existing in a solipsistic universe. With our desire to be understood, we want to know that others understand what it is like for us, and, similarly, we them.

Plus, we can go further. With the development of artificial intelligence (AI), how can we know when a computer becomes conscious? And if it is conscious, could we understand what that is like?

Isn’t this important if we develop conscious robots who could be harmed by what we require of them (for example, to fight in wars)?

More simply, if you have ever wondered whether the sky you see as blue is the same experience had by your friend (assuming they are not colour blind), or whether the sweet strawberry tastes the same to your partner, then you are playing with this idea of subjective conscious experience.

Can we ever truly know what it is like for someone or something else?

Join the conversation

How much can you really know what it’s like to be someone else?