Do you have to believe in reincarnation to be a Buddhist?
Reincarnation means there is a soul that goes out of your body and enters another body. That is a very popular, very wrong notion of continuation in Buddhism. If you think that there is a soul, a self, that inhabits a body, and that goes out when the body disintegrates and takes another form, that is not Buddhism.
When you look into a person, you see five skandhas, or elements: form, feelings, perceptions, mental formations, and consciousness. There is no soul, no self, outside of these five, so when the five elements go to dissolution, the karma, the actions, that you have performed in your lifetime is your continuation. What you have done and thought is still there as energy. You don’t need a soul, or a self, in order to continue.
You are more than just this body because the five skandhas are always producing energy.
It’s like a cloud. Even when the cloud is not there, it continues always as snow or rain. The cloud does not need to have a soul in order to continue. There’s no beginning and no end. You don’t need to wait until the total dissolution of this body to continue—you continue in every moment. Suppose I transmit my energy to hundreds of people; then they continue me. If you look at them and you see me, well, you have seen me. If you think that I am only this [points to himself], then you have not seen me. But when you see me in my speech and my actions, you see that they continue me. When you look at my disciples, my students, my books, and my friends, you see my continuation. I will never die. There is a dissolution of this body, but that does not mean my death. I continue, always.
That is true of all of us. You are more than just this body because the five skandhas are always producing energy. That is called karma or action. But there is no actor—you don’t need an actor. Action is good enough. This can be understood in terms of quantum physics. Mass and energy, and force and matter—they are not two separate things. They are the same.