> whereas languages with static typing are not easy to 'downgrade' to behave dynamically (?). That's not true. It's trivial to represent Python's "type system

> whereas languages with static typing are not easy to 'downgrade' to behave dynamically (?). That's not true. It's trivial to represent Python's "type system" in Haskell. An incomplete example of what that might look like: data Value = None | String Text | Dict (HashMap Text Value) | List [Value] Also, consider things like the very useful Data.Dynamic: https://hackage.haskell.org/package/base-4.3.1.0/docs/Data-Dynamic.html https://hackage.haskell.org/package/base-4.3.1.0/docs/Data-D... On the importance of early agility: I'm actually 100% in agreement that early agility is critical. In fact, I directly cite Bruce Eckel's arguments to that effect. However, if a business is going to remain agile in the long term, it should probably invest in "correctness tooling" sooner rather than later.