I had discussions with my advisor, the head of our Ph.D. program, a distinguished, experienced, disinterested professor, and my closest friends and colleagues. I re-read The Dip. I mulled over my thoughts. I made my decision. I parted from my research group.
I quit because I understood I have to change groups to get my Ph.D. The current situation did not work. It was a Cliff. I could not change the situation; I had to change situations. I saw the choice I had to make: I could squander time and energy—mine, my advisor's, my colleagues', the taxpayers', the world's—until I fell off a Cliff, or I could quit, and find a Dip where I will excel and flourish.
Today I quit.
I dedicate this post to the patience, understanding, advice, and aid of those who helped me make this decision. You have my deepest gratitude.