Before moving on to some more philosophical reading on emergence, I want to articulate a view of the concept. My purpose is to try to lay out my ideas in relatively precise language, and then engage with some of the previous work on the subject to see where, if anywhere, my view fits in. That engagement can then help ground any use of the concept moving forward.
My view starts with a claim. Consider a system that is said to exhibit emergent behavior, where the admittedly slippery concept of emergence is taken to be consistent with the conception I’ve already outlined. Assume that you have complete knowledge of the dynamics (rules, laws, etc.) at the microscopic level. Assume also that you have access to truly unlimited computational resources. Question – could you predict the macroscopic, emergent behavior? My claim is yes, you could. I’ll expand on some terms/phrases to better clarify the claim:
- Complete knowledge of microscopic dynamics: I mean truly complete, as if you yourself had written the rules or laws that pertain. Think Conway’s Game of Life – the rules can be listed in 3 simple bullet points. Also included here is a complete knowledge of the relevant initial conditions to arbitrary accuracy.
- Unlimited computational resources: This means unlimited even in practice. If prediction of emergent behavior would require more particles than exist in the known universe and more time than the present age of the universe, so be it.
- Predict: This means predict by simulating and observing the results of the simulation, not predict by understanding the microscopic dynamics, reflecting on their effects, and articulating some set of likely outcomes.
These claims lead me to a kind of epistemological view of emergence. A given system may exhibit some striking emergent macroscopic behavior. This behavior may be impossible for us, in practice, to predict, for a variety of reasons: uncertainty in empirical parameters of microscopic rules/laws, uncertainty in initial conditions, limits on computational resources, etc. However, if we understand the microscopic dynamics, we can say that our inability to predict the emergent behavior in practice is just that – only in practice. In principle, in the senses above, prediction is possible. The striking nature of the emergent behavior is then only striking in an epistemological sense – only because of the real-world limits on our knowledge.
Time to dig into some philosophical conceptions of emergence and find how this view might fit in.