Emergence is the phenomenon, where a complex entity displays properties that are absent from its constituent parts. Aristotle had realised that “… the totality is not, as it were, a mere heap, but the whole is something besides the parts …” (Book Η 1045a 8–10). Many more scientist and philosophers have analysed this phenomenon [1, 2]. The complex fractal shapes of snowflakes are a nice example of an emergent property that arises when many water molecules freeze (Figure 1A).
Now, I am going to take you through a hypothetical situation, which is going to be slightly far-fetched, in an effort to describe emergence. Imagine that an alien civilisation gets somehow, a sample of all the types of human cells. The cells are growing in liquid media and each type is isolated from the others. By studying these cells, the “alien” scientists, could never predict that when all these cell types are organised in a specific way, give rise to a multicellular organism, the human. Furthermore, it would be impossible for them to predict that humans can give rise to Parthenon, or leave the planet to go to the moon (Figure 1B). All these are emergent properties that appear after a critical number of entities come together and cooperate in specific ways.
Figure 1. A, B, Examples of emergence of novel properties, when “simpler” entities organise to a higher-order “meta-entity”.
Sources
[1] Mill, J.S., On the Composition of Causes, A system of Logic, Ratiocinative and Inductive. 1843: p. 371.
[2] Huxley, J.S. and T.H. Huxley, Evolution and Ethics. 1947: p. 120.