In the real world most employees would never fire themselves and HR would update things like payroll which the employee isn't allowed to change. Your example makes more sense as a justification for keeping a service layer.
In this case, I'm slightly gobsmacked that no-one pointed out that an employee is not their job. The contract of employment is a separate domain concept. So is the invocation of the clauses of that contract. Termination involves invoking a particular contract clause.
The job is to model a) the contract, b) the invocation of a specific clause, c) the record of that invocation (including its authorisations and so forth), and d) the consequential processing in other systems.
Whether you're working in FP, or Kay-style OOP, or Java-style OOP or, heck, SQL stored procedures, these are separate concerns, separate concepts, separate units of code, separate records, hopefully loosely coupled by whatever idiomatic form is at hand.
Yes, I agree in theory. What I meant to say is that many concepts don't map to physical objects.
> In this case, I'm slightly gobsmacked that no-one pointed out that an employee is not their job. The contract of employment is a separate domain concept.
This is what I mean by flamewars. Your solution sounds good, but there are other people on this same thread still arguing that it makes perfect sense for an employee to fire itself.
Employee object is not a representation of the will of the employee. It is an interface with operations that are best naturally acting on an Employee object -- changing its state.
Anyway, this is why I stay far, far away from OOP when I can - vast amounts of time spent on these questions which generate zero insight (at least the mathematical obsession with some parts of FP can be fun)