FP solves some issues but simultaneously introduces a new set of issues which creates new 'No true Scotsman' debates around ways to address those new issues...

FP solves some issues but simultaneously introduces a new set of issues which creates new 'No true Scotsman' debates around ways to address those new issues... It's like the joke that there were too many competing standards and so somebody decided to invent a new standard to make all the other standards redundant... The net result of this is that we end up with n + 1 competing standards. IMO, the biggest problem I often see with FP code bases is poor separations of concerns which leads to spaghetti code which is hard to read and maintain. When some state is not co-located the logic which is supposed to be operating on it, you're already throwing high cohesion out the window... And when you do that, it makes is harder to separate the responsibilities of different components because there is no clear ownership relationship between the logic and various bits of state... With FP state can end up being mutated all over the place and it's hard to know who did what.