knowledge

Knowledge refers to justified true belief in some classical analyses, though this definition has been debated since the Gettier problems. In contemporary epistemology, knowledge encompasses propositional knowledge (knowing that), procedural knowledge (knowing how), and experiential or acquaintance knowledge (knowing of or with someone or something). Knowledge can be explicit or tacit; explicit knowledge can be articulated, tacit is difficult to express.

Knowledge sources include perception (empirical evidence), reason and logic (a priori knowledge), introspection, memory, and testimony from others. The reliability of sources and the justification for beliefs determine knowledge claims. Justification can be foundational, coherent, or evidential. Knowledge is often distinguished from data and information: data are raw symbols; information is data organized and interpreted; knowledge is information integrated with context, justification and understanding.

In science, knowledge is supported by evidence, experimentation, and reproducibility. In everyday life, knowledge can be practical, such as knowing how to ride a bike, or factual, such as knowing that the sun rises in the east. Knowledge management refers to methods of capturing, distributing, and applying what is known within organizations or communities.

Limitations include skepticism, which questions whether knowledge is possible. Cultural and epistemic frameworks can shape what counts as knowledge and justification. The study of knowledge, epistemology, crosses philosophy, cognitive science, and information science, and continues to address how beliefs become justified, reliable, and useful in reasoning and decision making.