I'm still waiting to read of even a single example of a full-time employee who is working on (not preparing for) a business of their own while collecting a full-time salary. If it's such an awesome thing, there must be dozens of examples to choose from, right?
Why the silence? Because that employment arrangement does not work, and any person running their own full-time business would know why.
Working as a contractor while getting your business up and running? Great! That'll work fine.
Working as a full-time employee while starting a business? Doesn't work.
If you walk the talk and start your own company, you'll understand why you wouldn't want to be paying a person out of your own pocket while they're going through that process.
Quit worrying about what this employee can or can't do. Pay attention to what he does or doesn't do.
You're an entrepreneur or you're an employee. You cannot mix the two, and if you find the pills to start a business yourself you'll understand why.
Fuck. That. Shit.
Everyone is a contractor. There is no loyalty on either side of the employer-employee relationship. It is a hurtful delusion to harbor fantasies otherwise.
Judge an employee on their performance. Nothing more, nothing less.
What happens off the clock is none of your business. Literally.