The Need for Religion in Our Future Lives
How do we know that there is an after-life? According to Buddhism, although the nature of Cause and Effect may be different, they must have the same essential properties, they must have a definite connection; otherwise the same cause cannot result in the same effect. For example, the human body can be perceived—it has form and colour—and therefore, its immediate source or cause must also be formless. In analogy, the properties of the seeds of medicinal plants create medicine, and the seeds of poisonous plants create poison.
Most beings have physical bodies (though in some regions of existence beings have only minds). Both mind and body must have immediate sources. At the very moment of conception, both mind and body are formed and begin to function. The immediate source of a body is that of its parents. But physical matter cannot produce mind, nor mind matter. The immediate source of a mind must, therefore, be a mind which existed before the conception took place; the mind must have continuity from a previous mind. This we hold is proof of the existence of a past life. This has been demonstrated by the accounts of adults and children who remember their past lives—a phenomenon found not only in historical records but also observed today. We can conclude from this that past life existed, and hence that life in future will exist. If belief in after-life is accepted, religious practice is necessary as nothing else can supplant it, the preparation for one's future existence.
By H. H. the Dalai Lama of Tibet