I think it is correct to say that, in the functional paradigm, you effect change by making something new (and forgetting some older things.) Regardless of the paradigm (other than self-modifying code, perhaps) programs just are, but they must be evaluated if they are to do something useful.

I will leave that last sentence as I wrote it, but it immediately leads me to wonder if functions that write functions have wandered into the self-modifying code realm?