The basic game in Buddhism consists of a very large number of players called sentient beings, each of whom has a score called karma. It gets tricky though: while most of the time we can track a sentient being because it is attached to a physical body, those physical bodies are subject to gross impermanence, a.k.a. birth and death. How does the associated sentient being come to have whatever karma they do at the time they become associated with a newly born body? What happens to the karma of a sentient being when their body dies?
There is a similar problem in particle physics. There the players are elementary particles such as electrons and quarks. Each particle has a score which includes components such as position and momentum. Curiously, elementary particles are also subject to gross impermanence. What happens to the momentum of a particle when the particle ceases to exist? In physics, particles decay into other particles. Two particles might collide and both cease to exist as a result of the collision, but in their place new particles will appear. These newly appearing particles will carry the scores of the particles that have ceased to exist. In physics, quantities such as momentum are conserved. Momentum can be transferred from one particle to another but it cannot be created or destroyed. These conservation principles are the cornerstones of modern physics. The details of what kinds of particles there are and how they are created and destroyed, these details are constantly being reworked and refined through advances in theory and experiment. But a principle like the conservation of momentum is accepted more or less as an axiom. Of course every principle in science is subject to revision based on evidence. But conservation of momentum is so fundamental that some rather fanciful interpretations of the data will be allowed in order to maintain the conservation principle.
The understanding of beta decay is an example of such fanciful interpretation. Atomic nuclei are composed mainly of protons and neutrons, two types of particles. The simplest atomic nucleus is that of hydrogen, which consists of a solitary proton. This solitary proton is quite stable. Left to itself it will not manifest any sort of gross impermanence but will continue its existence indefinitely. Solitary neutrons, on the other hand, are quite unstable. They can be ejected from a complex nucleus through radioactive decay or through collisions, but they do not last very long outside a nucleus. What one observes is that the neutron decays into a proton and an electron. However, if the momenta of these new particles are added up, the sum will not be equal to the momentum of the neutron that disappeared. The great physicist Enrico Fermi posited a rather fanciful interpretation in order to preserve the principle of the conservation of momentum: there must be a third, invisible, particle also created alongside the proton and the electron. This third particle carries the missing momentum. Further physical principles showed that this third particle could only have tiny mass and would have no electrical charge, so Fermi called it a neutrino: like a very small neutron. These tiny particles were actually detected some years after Fermi’s prediction, one of the great successes of modern physics.
Karma is about as fundamental to Buddhism as momentum is to physics. Cultivate virtue and avoid evil: why? In order to improve one’s situation in the future. If the karma accumulated through one’s actions does not actually lead to future consequences, if karma can come or go independent of one’s actions, then the argument for cultivating virtue falls apart. For the most part it is not too difficult to see how karma might be accumulated and stored in association with a physical body. For example, it is not easy to see how memories are accumulated in a physical body, but it is clear that somehow they are. Karma is much like a habit, which is a kind of memory. The challenge comes when a body manifests gross impermanence, i.e. birth and/or death. We do not generally observe any kind of subtle body which could carry the karma to a newly born body or from a newly deceased body. But the situation is quite similar to beta decay in particle physics. We can maintain the principle of karma by hypothesizing the existence of such subtle bodies. And when expert observers use advanced methods that can actually detect such subtle bodies, we can have confidence in the accuracy of their reports.
The analogy with particle physics, where sentient beings are like particles and karma is like momentum, can be explored in other ways. Emmy Noether proved a mathematical theorem that provides some of the deepest structure in modern physics. She showed that conservation principles are associated with symmetries. For example, conservation of linear momentum is associated with the translational symmetry of space. The interchange symmetry of sentient beings seems like a natural reflection of the conservation principle of karma. After all, a modern paraphrase of the law of karma is: what goes around, comes around. What we do to others, we ultimately do to ourselves.
There is another perspective on the world, another way of seeing the world as a game, another system of accounting: economics. The players are economic agents such as individuals and corporations. Their scores are their property, which can be reduced to the single dimension of monetary value. The analogy between money and karma can shine a little light on the nature of money. Money, like karma, is relational. Karma is a pattern that relates sentient beings. Money is a pattern that relates economic agents. Henry Ford manifested this insight when he understood that the workers in his factories were also his customers. Naively he would maximize his wealth by raising the prices of the cars he was selling, and lowering the wages of the workers who made those cars. But in fact that naïve formula misses the fact that money lives by flowing in a network. Stationary money is dead money.
Particle physics can provide some further insights to challenge our understanding in Buddhism and economics. The wild thing about particles is that they don’t exactly exist or not exist at any particular time. This is very much in line with the argument of the Buddhist sage Nagarjuna, who showed that atoms cannot exist. One of the fascinating manifestations of this kind of quasi existence of particles is associated with the physics of crystals. Particles such as holes and phonons exist in crystals but not in empty space. Particles exist as collective behaviors of other particles. Particles become a way of understanding a system rather than parts whose existence is prior to the system.
This kind of shifting perspective can be seen in another game, in biology. At one level, biology is about organisms and their interactions. At another level, it is about species. Species can compete with other species much like organisms can compete with other organisms. At yet another level, biology is about genes. The evolution of a species can be viewed as a competition among the genes in the gene pool of the species.
This shifting perspective creates some of the great challenges of our time. Climate change is a consequence we all experience of actions we all perform. Individual persons can act, municipalities can act, corporations can act, nations can act, international organizations can act: these are not separate actions, but different perspectives on actions. The fact that we can see a situation as actions by, and consequences for, different sorts of beings, depending on the perspective we choose to take: this does not imply that these actions and consequences are not real. On the contrary, it is just this resilient play, this presentation of fresh appearance to every perspective, that makes the system real, that makes the world real. There is always more to learn.