This document discusses perception and how we perceive the world through our five senses of sight, sound, touch, taste, and smell. It explains that perception provides primary knowledge as we learn from our experiences. However, perception involves both sensation from the external world and interpretation by our minds, so perceptual illusions are possible. Context, expectations, beliefs, interests and emotions can all influence our perceptions. While perception gives us knowledge, we can sometimes misinterpret what we see or remember incorrectly.