Disease

After David’s first year of college he comes home and visits with his 95 year old bubbe. During his visit, she asks him, "So my lovely bubbeleh, vhat are you going to be vhen you grow up?"

David replies, "I'm going to be a doctor of philosophy, bubbe."

"Oy, oy, that's vunderful, David," says his bubbe, "but vhat kind of disease is philosophy?