the world around us consists of various kinds and levels of physical energy. our knowledge of the world comes through our sense organs, which react to these energies. certain wavelengths of electromagnetic energy stimulate our eyes. our ears sense certain kinds of mechanical vibrations in the air. our noses and tongues are sensitive to certain chemical stimuli. sense organs in our skin respond to pressure, temperature changes and various stimuli related to pain. sense organs in our joints, tendons, and muscles are sensitive to body movement and position.

the sense organs change the various environmental energies into nervous impulses, and these impulses then go to the brain. through the psychological process of perception, the patterns of energies become known as objects, events, people, and other aspects of the world.

the process of perception does not reveal objects and events of the world. we see light and color, but there is no light or color in the electromagnetic waves that stimulate the eyes. in the same way, there is no music or noise in the vibrations that stimulate the ear. the brain organizes and interprets nervous impulses from the eyes as light and color, and impulses from the ears as sound. together, the sense organs and the brain transform physical energy from environmental stimuli into information about the events around us.

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