午夜剧场

"Once upon a time, Zhuang Zhou dreamed he was a butterfly, a butterfly flitting and fluttering around."

This is the opening of the Chinese fable (from the State of Song during the Warring States period) commonly known as the "Butterfly Dream." In the dream, Zhuangzi (Zhuang Zhou), who had become a butterfly, was dancing through the air, oblivious to his true self. However, when he suddenly awoke, he returned to being Zhuangzi. Was Zhuangzi dreaming of being a butterfly, or is the form of Zhuangzi itself a dream being seen by a butterfly?

Zhuangzi's philosophy aside, this problem is extremely interesting when considering the role played by the brain. In fact, the rich world we experience is nothing more than the true world—once broken down into sensory information—reassembled within the brain. If information constituting the true world cannot be acquired, 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 no small extent, and it is possible that every phenomenon we can know is 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 a glimpse of these fragments. For example, although we do not perceive a time lag in the ever-changing world, a delay of several 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 several tenths of a second is its current state. Furthermore, in reassembling the fragmented 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 one were to externally manipulate brain information processing 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 itself be a "Butterfly Dream"?