Experience is what happens to you and how it feels. It includes perception, emotion, thought, and action. It is the stream of consciousness that makes up your life. Philosophers have asked whether experience is the foundation of knowledge, whether it can be trusted, and whether it is private or shared. Empiricists say knowledge begins with experience. Rationalists say reason can grasp truths experience cannot. Kant tried to synthesize them, arguing that experience is structured by categories the mind brings to it.

Phenomenologists study the structure of experience. Husserl analyzed intentionality, the fact that experience is always experience of something. Merleau-Ponty emphasized the lived body as the medium of experience. William James described the stream of consciousness, with its fringes and transitions. In Eastern philosophy, experience is often the focus of meditation and introspection. The question of whether experience is subjective or objective, private or public, remains central. Nagel's essay "What Is It Like to Be a Bat?" argued that subjective experience cannot be fully captured by objective description. That gap is the hard problem of consciousness.

Dimensions of experience

• Perceptual. Sight, sound, touch, taste, smell.
• Emotional. Fear, joy, anger, love.
• Cognitive. Thinking, remembering, imagining.
• Bodily. Movement, balance, pain, pleasure.

Experience is both the starting point of philosophy and one of its hardest problems.