Over a few weeks, I came to comprehend that the sound of one hand clapping is an illusion. The hand’s movement mimics clapping, but the only way to make the illusion a reality is to add a second hand. The sound of one hand clapping can be imagined, but the clap doesn’t exist until another hand is present. With that realization, I recognized the koan’s question as a way to understand the Buddhist doctrine of emptiness (śūnyavāda in Sanskrit), which says that no individual thing or person has any intrinsic existence, but exists only relationally, dependent on everything else. The concept of an individual nature is, like one hand clapping, an illusion.