IN Christian Science, ideas are understood to originate in the divine Mind, Spirit, the only cause or Principle of existence. Consequently they are spiritual, substantial, immutable, eternal, harmonious, indestructible, and ever available. Beliefs, on the other hand, are the transient illusions of material sense, springing from a supposititious mind opposed to the divine Mind, God. They have no cause and are not themselves cause, since God, Spirit, is the only creator.
So long as humanity seeks cause in matter or belief, it will be misled. Christian Science shows matter to be but another name, an alias, for mortal mind. In the Christian Science textbook, "Science and Health with Key to the Scriptures," Mary Baker Eddy writes (p. 293): "Matter and mortal mind are but different strata of human belief. The grosser substratum is named matter or body; the more ethereal is called mind. This so-called mind and body is the illusion called a mortal, a mind in matter. In reality and in Science, both strata, mortal mind and mortal body, are false representatives of man."
Because the mental state governs the physical in every case, the student of Christian Science learns to detect and reverse the wrong thinking or belief which is at the bottom of physical discord. Climate, food, contagion, accident, heredity, fear, worry, hatred, envy, selfishness are said to be procuring causes of disease; but these causes are unreal because they lack the divine Principle, God. Actually they, and disease by whatever name it may be called, are "but different strata of human belief," alike causeless and illusory; and they are destroyed by the understanding that God is the only cause and effect, the only Mind.