Question: Are there circumstances in which it is right to use force to defend oneself?
In order to tell if it is right - pay attention to your consciousness. If the mind is in equilibrium, then always your actions will be for a larger cause. It may sometimes appear difficult. The first two dharmas - looking after the physical body and then looking after the mind are easy, but always I say that the third dharma - moral action - is the most difficult. But if the mind is controlled, then you will know if your action is moral.