When doctors vaccinate a patient, their intention is to expose him or her to a weakened form of a disease-causing pathogen and thus to make the patient better able to resist the pathogen and less likely to develop a severe form of that disease later.
Doctor's Goal
Help a patient to avoid a severe form of a disease.
Doctor's Method
Give the patient a vaccine with a weakened form of that disease, so that the patient will be better able to resist that pathogen later.
Implicit Principle
We want something like, .
i.e.