The 2 generals problem illustrates the problems with this. You can’t just call a function over an unreliable communication channel and expect it to work the sam

The 2 generals problem illustrates the problems with this. You can’t just call a function over an unreliable communication channel and expect it to work the same way. Solving this in the general case for every function call is difficult. Pure functions are idempotent, so you can retry everything until nothing fails. But once you add side effects and distributed state, we don’t know how to solve this in a completely generalized and performant way.