Atsushi Aoyama: Seeing "The Butterfly Dream" in the Brain

2018/07/17

"Once, Zhuang Zhou dreamed he was a butterfly. A butterfly flitting and fluttering about."

This is the opening of a Chinese fable (from the State of Song during the Warring States period) commonly known as "The Butterfly Dream." In the dream, Zhuangzi (Zhuang Zhou) became a butterfly and flew about, losing himself. But when he suddenly woke up, he returned to being Zhuangzi. Was Zhuangzi dreaming of being a butterfly, or is the figure of Zhuangzi itself a dream being seen by a butterfly?

Setting aside Zhuangzi's philosophy, this problem is extremely interesting when considering the role the brain plays. In fact, the rich world we experience is nothing more than a reconstruction within the brain of the true world, which has been temporarily broken down into sensory information. If information constituting the true world cannot be obtained, contradicts other information, or is ignored for some reason, the brain interprets the world in a way that is convenient for itself. Therefore, the true world and the reconstructed world differ to some extent, and all events we can know may be a "Butterfly Dream" created by the brain.

Conventionally, it was technically quite difficult to approach the mechanisms of such brain functions. However, with the development of technology to precisely measure brain activity from outside the head, it has become possible to catch glimpses of these fragments. For example, although we do not perceive a time lag in the ever-changing world, a delay of a few tenths of a second exists within the brain until the reconstruction process is complete. In other words, we are under the illusion that a world delayed by up to a few tenths of a second is its current state. Furthermore, when reconstructing the disassembled world, the brain understands which pieces of information should be linked together. Even if a human is exposed to an unknown environment where these linking rules cannot be applied, they will acquire new rules through long-term learning and adapt flexibly to the environment.

As described above, sophisticated brain information processing exists as an intermediate process between the true world and the reconstructed world. Therefore, if brain information processing could be manipulated externally, as in science fiction works, a "Butterfly Dream" in the true sense could be realized... and as I write this, I suddenly wonder: could the very act of writing this text also be a "Butterfly Dream"?