Given that the argument was that humans couldn't continue to learn and grow after they're dead, maybe work isn't an option for them either. They didn't think Patty COULD learn more mathematics or philosophy after she was dead, so they told her she couldn't.

Oh, that's such an interesting thought! It would be so disheartening to have your passions taken away, as well as your loved ones and your entire previous life...

I really have to agree with your opium comparison, too.