Newton observed that a body in motion tends to stay in motion unless acted upon by some outside force. This so-called law of inertia concerns the physical world but also seems to hold true in psychology (and here).
Endnote. Some notable books that I’ve read since my last Muse post have included Talks with Sri Ramana Maharshi, Final Talks by Annamalai Swami and The Book by Alan Watts. These concern beyond mindfulness, to which Ramana Maharshi points to here [p73]
What advantage is there in meditating for ten hours a day, if in the end that only has the result of establishing you a little more deeply in the conviction that it is you who are meditating?
Do not meditate—Be!
Do not think that you are—Be!
Don’t think about being—you are!