Meditation for Happiness, Health, and Self-knowing: Now (Amazon Kindle) has an addendum loaded with koans. Solutions to these conundrums will be posted on this blog.
If you have not yet read it or thought of a solution, do so prior to reading each solution. The following is an acceptable solution to the fifteenth koan.
Roshi: Nothing. Into this bowl place some beginning, self, darkness, cold, ignorance, depression, and slowness. Into the other bowl place some, ending, non-self, light, heat, wisdom, bliss, and speed.
Things appear to be unique. By using an electron microscope and other measuring instruments one may see that no two things are exactly alike. The perception that each thing has a unique quality that is independent from all other things is an illusion.
We can verify this by analyzing, testing, and dissecting each thing into its components. What remains when each constituent is identified? Nothing. Each thing is empty of a unique intrinsic identity that holds together and organizes the pieces.
And science has demonstrated that all phenomena are interdependent. When 2 or more people are interacting, the feelings of one affect the feelings of others. This concept is referred to as the fluttering butterfly being one of the contributing causes to a hurricane thousands of kilometers away. In physics, it is referred to as action at a distance.
Instead of focusing on appearances, the roshi is referring to essence. That essence is more than existence. Being is empty of a unique organizing identity and it is interdependent.
Though the temperature today and yesterday was 73 F, to one individual it felt warmer and to another it felt colder. When various witnesses to an accident convey their understanding to the jury, their perceptions often vary significantly. When hearing the teachings of religion H and religion Q, one individual may label one as good and the other as bad. These examples show that our conditioning/subjective states influence our perception of things.
Because things are not essentially unique and independent, they all have the properties of emptiness of uniqueness and independence. Being of one is the same as the being of another. The being of the many is the same as the being of one.
Do humans have the above characteristics of things? Indeed. That implies that the sense of self, to which each of us cling firmly, is valid in the world of appearances. Yet, it indicates that there is no essential identity that may be found within the mind/body/personality/personal memories. Think of the implications of this. What affect does it have on your meditation practice and relationships?
Hundreds of books have been written about this for over 20 centuries. These may help you to sort it out.