Is it beyond our grasp, even in principle?

Illustration: María Elena (Mani) Hinojosa

In his paper “What Is It Like to Be a Bat?”, American philosopher Thomas Nagel argues that humans can’t know what it’s like to be a bat, to experience its conscious mental states. This assumes that bats have a conscious experience beyond mere sensory perception (a reasonable assumption, as they’re mammals). Nagel says that even if we could somehow directly sense the behavior and perceptions of a bat, without modifying our brain structure our subjective experiences would not resemble the bat’s experiences at all.

I think Nagel is right. We could further point out that even if we knew everything there is to know about the functioning of a bat, to the point where we could predict unfailingly and exactly how it would react to different stimuli and behave under any and all circumstances, we wouldn’t really know everything about it without experiencing its subjective mind ourselves.

This is related to the thought experiment known as “Mary’s room”. In a simplified formulation, Mary is a brilliant scientist that specializes in the perception of color. She learns absolutely everything there is to know about it, but she herself lacks the ability to perceive color. Then one day she acquires this ability for the first time. What are the implications?

Some think this thought experiment shows that consciousness can’t be part of the physical world, because, even though Mary knew all about color and color perception, the corresponding subjective experience remained beyond her grasp before she gained the ability to perceive color. Others, perhaps fearing such a conclusion, deny that any new knowledge was acquired by Mary. I don’t agree with either position:

I think this thought experiment simply illustrates that no one can fully understand another being without having its subjective experiences. A fundamental aspect would be missing regardless of how much else was known.

At any rate, is it really the case that, even in principle, we can’t ever experience what it’s like to be a bat? Could we not in the future expand our brain capabilities and structure to incorporate those of a bat?

Bats are an apt choice for thinking about this because they have a sensory system, called echolocation or bio sonar, which is different from any of ours. Bats produce sounds that create echoes from surrounding objects, which allows them to navigate and hunt in the dark. But this system is not completely removed from our capabilities, as people trained to orient by echolocation can interpret the sound waves reflected by nearby objects, accurately identifying their location and size.

So a better choice still would be an animal capable of electrolocation, which is the ability to detect other animals through bioelectric fields. This would be even harder for us to imagine than a bat’s sonar.

If we wanted to at least approximate the subjective experience that, say, a fish may have of electrolocation, it wouldn’t be enough to attach sensors to our body for detecting electric fields. We’d need an area in the brain designed to receive, process and interpret this novel input, an area that, naturally, we lack. We might perhaps, through training, learn to generate mental images from the input, but this would not replicate the “visualization” of the fish, if indeed the fish generates any kind of mental visualization at all. We’d have to connect the input to a totally new brain-like structure that would process and interpret the input exactly as the fish would.

Let’s suppose that we manage to create such a structure. Then we connect it to the electric-field sensors and to our own brain through a sort of brain-computer interface provided by Elon Musk’s Neuralink. Or maybe we manage to connect our brain to the fish’s brain itself! Anyway, it would be like expanding our brain. While thus connected, we might be able to experience electrolocation as the fish would (we could never aspire to experience the totality of the fish’s consciousness, as for that we’d just have to become the fish…). The question is: what happens when we disconnect from the brain interface? Would we be able to remember the experience? Probably not, or at best only dimly. When we imagine or recall a sensory perception, we engage the same neural circuitry that is activated when the actual perception takes place. Inputs from different sensory organs are processed in different parts of the brain, and we’d no longer have access to the external brain where the electric field input was processed, nor anything remotely similar in our own brain. It follows that we’d be unable to remember what it was like to be partially a fish.

In sum, the most we could hope for through future technology would be to roughly feel some of the subjective experiences of certain animals, but it seems that the more we expanded our consciousness to encompass theirs, the less we’d be able to retain afterwards, unless we decided to remain in a sort of cyborg state.

Interested in natural selection, evolutionary psychology, neuroscience, science in general, human nature, consciousness, philosophy and ethics.

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