Knowledge

Knowledge is an <a href="/facts/Declarative_knowledge/JMKfKmu7">awareness of facts</a>, a <a href="/facts/Knowledge_by_acquaintance/mIjvledD">familiarity with individuals and situations</a>, or a <a href="/facts/Procedural_knowledge/gYBuANxo">practical skill</a>. Knowledge of facts, also called <a href="/facts/Proposition/0877MFMD">propositional</a> knowledge, is often characterized as <a href="/facts/Truth/NyQmBtUC">true</a> <a href="/facts/Belief/HbPvkGT6">belief</a> that is distinct from opinion or guesswork by virtue of <a href="/facts/Justification_(epistemology)/CxWaj0pY">justification</a>. While there is wide agreement among philosophers that propositional knowledge is a form of true belief, many controversies focus on justification. This includes questions like how to understand justification, whether it is needed at all, and whether something else besides it is needed. These controversies intensified in the latter half of the 20th century due to a series of thought experiments called <a href="/facts/Gettier_cases/bBQT9H7o">Gettier cases</a> that provoked alternative definitions.
Knowledge can be produced in many ways. The main source of <a href="/facts/Empirical_knowledge/JUaYSGJc">empirical knowledge</a> is <a href="/facts/Perception/xLK0n2q4">perception</a>, which involves the usage of the <a href="/facts/Senses/n9kYQ3rf">senses</a> to learn about the external world. <a href="/facts/Introspection/X8rBdaR0">Introspection</a> allows people to learn about their internal <a href="/facts/Mental_states/sHsDj380">mental states</a> and processes. Other sources of knowledge include <a href="/facts/Memory/zucwQIEX">memory</a>, <a href="/facts/Rational_intuition/stJIX3kK">rational intuition</a>, <a href="/facts/Inference/RBbe95bP">inference</a>, and <a href="/facts/Testimony/dxgk0txp">testimony</a>. According to <a href="/facts/Foundationalism/2hlTEXTg">foundationalism</a>, some of these sources are basic in that they can justify beliefs, without depending on other mental states. <a href="/facts/Coherentism/7JRS1DLe">Coherentists</a> reject this claim and contend that a sufficient degree of coherence among all the mental states of the believer is necessary for knowledge. According to infinitism, an infinite chain of beliefs is needed.
The main discipline investigating knowledge is <a href="/facts/Epistemology/NsDwpcYH">epistemology</a>, which studies what people know, how they come to know it, and what it means to know something. It discusses the value of knowledge and the thesis of <a href="/facts/Philosophical_skepticism/xsNp72xg">philosophical skepticism</a>, which questions the possibility of knowledge. Knowledge is relevant to many fields like the <a href="/facts/Science/IJoaD7rs">sciences</a>, which aim to acquire knowledge using the <a href="/facts/Scientific_method/182j8RWE">scientific method</a> based on repeatable <a href="/facts/Experimentation/esltM54f">experimentation</a>, <a href="/facts/Observation/NTodmzCo">observation</a>, and <a href="/facts/Measurement/rsLLbn1s">measurement</a>. Various religions hold that humans should seek knowledge and that God or the divine is the source of knowledge. The anthropology of knowledge studies how knowledge is acquired, stored, retrieved, and communicated in different cultures. The <a href="/facts/Sociology_of_knowledge/6sYx7KnC">sociology of knowledge</a> examines under what sociohistorical circumstances knowledge arises, and what sociological consequences it has. The <a href="/facts/History_of_knowledge/TDz7w3MP">history of knowledge</a> investigates how knowledge in different fields has developed, and evolved, in the course of history.

Knowledge open-in-new

Knowledge