Learn something new everyday.
The term "center of gravity" goes all the way back to William James!
" . . .It is assumed to reflect a person's most ego-syntonic and habitual frame of reference or preferred mode of responding to life. James, (1902) refers to this as a person's "center of gravity," a particularly felicitous metaphor."
-Susanne Cook-Greuter, Postautonomous Ego Development: A Study of Its Nature and Measurement 1999,2005 pg. 27
 
Incidentally: 
syn·ton·ic   –adjective 
| 1. | Electricity. adjusted to oscillations of the same or a particular frequency. | 
| 2. | Psychiatry. of or denoting a personality characterized by normal emotional responsiveness to the environment. | 
"With whom or with what are you in communion at this moment?"
 . . ."I?" he replied, almost mechanically. "Why not with anyone or anything."
"You must be a marvel . . . if you are able to continue in that state for long."
    -Constantin Stanislavsky