Introspection is the examination of ones own conscious thoughts and feelings. It is a psychological process that involves looking inward to examine ones own thoughts, emotions, judgments, and perceptions. Introspection is generally regarded as a process by means of which we learn about our own currently ongoing, or very recently past, mental states or processes. It is a means of learning about one’s own mental states or processes, and not about affairs outside one’s mind, at least not directly.

Introspection is closely related to human self-reflection and self-discovery and is contrasted with external observation. It generally provides a privileged access to ones own mental states, not mediated by other sources of knowledge, so that individual experience of the mind is unique. Introspection can determine any number of mental states including sensory, bodily, cognitive, emotional, and so forth.

Introspection has been a subject of philosophical discussion for thousands of years. The philosopher Plato asked, "…why should we not calmly and patiently review our own thoughts, and thoroughly examine and see what these appearances in us really are?". In psychology, introspection is the chief method of psychology in a dualistic philosophy, which divides the natural world (matter, including the human body) from the contents of consciousness.

In summary, introspection is a process of observing ones own mind with a view to discovering the laws that govern the mind. It is a means of learning about ones own mental states or processes, and not about affairs outside ones mind, at least not directly. Introspection is closely related to human self-reflection and self-discovery and is contrasted with external observation.