The fact, as stated in Christian Science, that Spirit is substance, is revolutionary. The education of the so-called human mind has been chiefly towards the acceptance as substance of what the five personal senses cognize. Hence matter and its phenomena have been accepted as material manifestations of substance. Even man has often been assumed to be material in substance, thus limiting him in every direction. Christian Science affords an opposite point of view, and shows the falsity of all material beliefs.
In support of the statement that Spirit is substance, Christian Science offers the proposition that God is Spirit, and thus sets forth Spirit as the divine Principle of the universe. This results in the overthrow of the belief that a physical body can be man, and that the substance of Spirit can be made manifest as matter. There can be no such thing as spiritual matter. Jesus said, "That which is born of the flesh is flesh ; and that which is born of the Spirit is spirit." Since Spirit is substance and man the image and likeness of Spirit, Spirit is the substance of man. The acceptance of this fact opens up boundless possibilities; for what is true of God as substance must be true of man as Spirit's image and likeness. Hence it is also true that God supplies all that is needed to sustain man. Conversely, man bears witness to the fact that God, who is his Father, provides abundantly for man's every need.
One would not expect to look at himself in a mirror and see anything unlike himself reflected there. The image in the mirror is exactly like the original. Do we not sometimes lose sight of the law of spiritual reflection and fail to remember that, inasmuch as man is the reflection of Spirit, our great need is spiritual understanding? Do we not sometimes cherish the false belief that man is made up of substance that is disease-producing, or subject to disease? If we hold to the law of cause and effect, if we remember that like always produces like, must we not then accept the conclusion that Spirit, God, cannot be manifested in diseased conditions of any name or nature? If we are striving to help another to know the unreality of disease, can we do this by accepting what material sense says, as true testimony regarding the substance of man? Spirit being substance, no evidence can be accepted but that of the spiritual senses. The material witness and the material evidence must be rejected as the liar and its lie. Spirit being God, true substance is self-existent and eternal. Man is therefore altogether indestructible. He cannot consume with disease because of matter's claim to be a lawgiver.