Science of being:

Mary Baker Eddy titled one of the chapters of Science and Health "Science of Being".

Below is a quick reference to selected passages from Science and Health in which she uses the term:

[S&H p. 492] God is Mind, and God is infinite; hence all is Mind. On this statement rests the Science of being, and the Principle of this Science is divine, demonstrating harmony and immortality.

[S&H p. 517] Divine Love blesses its own ideas, and causes them to multiply,--to manifest His power. Man is not made to till the soil. His birthright is dominion, not subjection. He is lord of the belief in earth and heaven,--himself subordinate alone to his Maker. This is the Science of being.

[S&H p. 302] The Science of being reveals man as perfect, even as the Father is perfect, because the Soul, or Mind, of the spiritual man is God, the divine Principle of all being, and because this real man is governed by Soul instead of sense, by the law of Spirit, not by the so-called laws of matter.

[S&H p.340] The divine Principle of the First Commandment bases the Science of being, by which man demonstrates health, holiness, and life eternal.