The Principle of Refraction Explains Illusions in Color Perception

The ability to see forms requires light, which is one of the conditions for perceiving forms. Without light, forms cannot be seen. Light functions to reveal the form dust. As long as the form dust is within the light source, it reveals the form dust. Then, the Tathāgatagarbha extracts the four great elements from the form dust and transmits them to the gross sense faculty of the eye. Subsequently, through the neural transmission system, it is conveyed into the black box. However, the forms and other objects of the six dusts recognized by the eye consciousness are all illusory reflections, differing to some extent from the original six dusts. The six dusts within the black box are not the substantial external dust realms but are illusory images reflected in a mirror.

The principle of refraction can explain that the form dust seen by the eye consciousness within the black box is not the true, original form dust from outside but a transformed version resembling the original form dust—it is not the true form. The propagation of light has a certain speed, which varies in different media due to differences in their material structures, resulting in varying degrees of resistance. When light passes through two different media, its direction changes at the interface between them, causing refraction. If form dust happens to appear at this interface, light will reveal it there, and the image revealed in the two media will undergo changes.

For example, air and water are two different media with varying resistance to light propagation. When light travels from air into water, its direction changes, causing the revealed form dust to appear altered, though the form dust itself remains unchanged. For instance, if a chopstick is half-submerged in water, light reveals the part in the air and the part in the water separately, causing their positions to shift. As a result, the eye consciousness perceives the chopstick as bent. Does this phenomenon of bending occur within the black box of the supreme meaning faculty, or does it appear in the external form aspect of the essential realm before being transmitted to the eye faculty?

If the chopstick in the essential realm of the external form dust were truly bent, what would happen when it is removed from the water? Would it remain bent? The chopstick in the essential realm does not change, regardless of the medium it is in. Otherwise, it would alter when removed from the medium, but in reality, it remains unchanged, just as before. Does the black box deceive? Does the eye consciousness deceive? Do you still trust your own eyes? Do you believe that everything you see is real? Do you believe that all dharmas discerned by your six consciousnesses are real? Are you still confident? Do you still spend your days commenting on this and that, asserting what is right or wrong? Have you truly understood anything?

Even witnessing someone stealing with your own eyes may not mean they are actually stealing. Catching someone red-handed with stolen goods may not reflect the truth. Witnesses and material evidence may not be genuine. Scolding and hitting you may not signify hatred. Care and concern for you may not indicate love. Sharp words may not imply harshness. Thunderous force may not denote cruelty. If your vision is distorted, you cannot perceive the truth. If the light of your mind is distorted, you cannot perceive reality.

The apparent bending of the chopstick is actually an illusion brought about by light; the chopstick itself is not bent. It occurs because the direction of light propagation changes, causing the relative position of the chopstick to appear altered, though in reality, it remains unchanged. The Tathāgatagarbha transmits the reflected images of the two sections of the chopstick revealed by light into the supreme meaning faculty, and the eye consciousness perceives a bent chopstick.

Similarly, when sunlight enters water, the direction of the light beam changes, making the water appear shallower than it actually is. The shallowness is an illusion perceived by the eye consciousness. The light beam also makes the position of a fish in the water appear shallower, causing you to miss when trying to catch it based on that perceived location. The fish is not where your eye consciousness sees it but is instead at an angle below that position, beyond the perception of the eye consciousness.

Light can bring us illusions, and so can darkness. In the dark, one often feels that there is something frightening, unpredictable, or uncontrollable that might threaten or harm oneself. In reality, there is nothing there—it is merely the solitary consciousness indulging in wild thoughts.