Nichiren on Karma

So, what is karma anyway? Karma is not cause and effect. Karma is not good or bad or indifferent. Karma is not retribution or a behavior or an act of will or bad habit or human vice. Karma is momentum.
We live in a period of human development when very few of us are unfamiliar with the terminologies of science in our daily speech. I want to speak in terms familiar to as many of us as I can. So this writing will include many familiar concepts and terms in order to provide a working mental framework for insight into the nature of karma, Buddhist thought, and deeper understanding of the discussion of karma. I am not inventing some pseudo-science here to upset the academic pursuits of scientific discoveries, rather I am applying some attributes of scientific method to construct a logical mental exercise to grasp the profound significance of Buddhist thought and understanding of the "Engine of Life".