A Shadow is an area or image of darkness projected on a surface caused by an object intercepting a light source. The optical phenomenon, creates a silhouette. A Shadow's circuits to some extent repeats the contours of the light barrier. Depending on the environment of its passage, the intensity and angle of his fall, its color characteristics, direction and distance from the object and the surface, and the last - of each other, the nature of texture, reflectivity, transparency and shape of them - can change the sharpness and hardness of circuits, the degree of contrast with the surface, the depth and darkness of coloring this silhouette (with barely perceptible, pale gray or dull color - to very dark color, and velvety-black). If there is contact between the object and the surface, the shadow will certainly have a "touch" with him, and in the absence thereof - object casts a shadow on the surface as well as the silhouette figures, repeating its outlines, and meet all of the above conditions, but isolated from it (number of amendments makes no factor of this contact, affecting the uniformity in color and silhouette). The shadow will be completely or partially cover the objects in between it and the objects closest to the radiation source. It occurs on the surface of the object itself - from the light source, and the presence of one such source and opacity, it will be deeper than - the bed to an independent surface, but the dark side of the object can also be obtained from the reflection of the surface or other objects . This empirical determination significantly epistemologically different from the one given to this phenomenon: physics, which operates the concepts of phase states of matter, the wave nature of light and optics - The psychology of color perception and physiology of vision. The concept of a "shadow" has a lot of allegorical, metaphorical and figurative sense, present in everyday life, literature, art, psychology, and natural sciences. Special attention is paid to this notion in the philosophical systems, the most - in the east, for example, the "shadow" of the ancient Chinese philosophy and art, depending on the context, represent several categories. The word "shadow" in some cases may serve as a synonym for the word ghost ("the shadow of Hamlet's father").