> Immutability is a very useful tool since you have have any kind of dependency -- direct, indirect, implied, etc) -- and there's no worry. But you still need a

> Immutability is a very useful tool since you have have any kind of dependency -- direct, indirect, implied, etc) -- and there's no worry. But you still need a mechanism to manage mutating data. I agree. For me it feels like immutable data is a tool, not a universal principle. For example, in low-level C programming or direct control of a register in an embedded context, immutable data isn't a principle, it's just another approach. What I mean by "universal" is something like SOLID. [1] (Most people only use SOLID for OOP, but Uncle Bob makes it clear in Clean Architecture that he thinks SOLID is universal, and not limited to OOP.) That said: it does feel like immutable data should be the _default_ approach in many situations. But that's really hard to do in most languages. [1] https://www.amazon.com/Clean-Architecture-Craftsmans-Software-Structure/dp/0134494164 https://www.amazon.com/Clean-Architecture-Craftsmans-Softwar...