SEEING is often synonymous with understanding. A common expression in everyday life is, "I see," meaning, "I understand or comprehend." When Jesus said (Matt. 13:16), "But blessed are your eyes, for they see," he had been explaining that he spoke in parables because the people closed their eyes and ears to his teachings, and he was commending the disciples upon their open or receptive thought, which brought spiritual understanding.
In the Christian Science textbook, Science and Health, Mrs. Eddy elucidates the truth which Jesus taught. In her definition of God in the Glossary of the textbook she includes the word "all-seeing." She writes (p. 587): "God. The great I am; the all-knowing, all-seeing, all-acting, all-wise, all-loving, and eternal; Principle; Mind; Soul; Spirit; Life; Truth; Love; all substance; intelligence." She understood God to be the only creator or cause, the source of all faculties, the fountain of all good, and the infinite All expressing His deific nature in man and the universe.
God, the only cause, causes man to see, to perceive all that is real and knowable. Man in God's likeness sees because God sees, and nothing can change this spiritual fact. There is one sight, the indivisible discernment of the all-knowing and all-seeing Mind, which is God, and each child of God reflects this sight individually. One who understands this is blessed with good human eyesight.