To be strictly consistent, the philosopher who discovered this truth should forthwith stop eating, drinking, or preaching his discovery, and should simply lie immobile until dead. Since few philosophers take this course of action, it must be assumed that few of them really believe their own doctrines. Monists and dualists. Another distinction is between monistic and dualistic pantheisms. Dualists believe that there are two types of substance or principle in the universe.
Most dualists see some tension between the two principles.
By contrast, monists believe that there is only a single type of substance in the universe. Idealists like Mahayana Buddhists or Greek Eleatics are often termed monists. Certainly they believe that there is only one substance in the universe, and that substance is essentially mental in character. However, they cannot ignore the world of phenomena which everyone, including them, has to deal with every day. Indeed they have to spend a great deal of effort explaining to a healthily sceptical audeince why the unreal real world appears to exist, why it is the same for all of us, and so on.