Genetic Purity Fallacy

There is a theory that a coin is strongest when validation is performed by a common implementation. According to this theory the complexity of consensus rule implementation implies a likelihood that multiple implementations will diverge, resulting an inadvertent chain split. The split implies financial loss by people on the weaker side of the split.

Based on the assumption of high complexity, each update to the "one true client" produces the same likelihood of divergence. Similarly, dependency on external independently updated libraries has the same effect. In the case of the initial Bitcoin implementation both upgrade of the client and upgrade of an external dependency have resulted in unintended chain splits and material financial loss.

A single implementation produces a weakness directly analogous to that of a living species with genetic uniformity. In the case of a single implementation, both internal and external updates penetrate the economy quickly and deeply. The financial impact of a split is therefore more significant than that caused by a less widely-deployed implementation. In a scenario where ten implementations each supporting an even fraction of the economy there would be risk to at most 10% of the economy for any given update, whereas the update of a single universally-deployed implementation reaches the maximum split risk of 50%. The theory is therefore not only invalid but expresses the opposite of actual behavior.