Knowledge is an awareness of facts, a familiarity with individuals and situations, or a practical skill. Knowledge of facts, also called propositional knowledge, is often characterized as true belief that is distinct from opinion or guesswork by virtue of justification. 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 Gettier cases that provoked alternative definitions.

निरपेक्ष सत्य की स्वानुभूति ही ज्ञान है। यह प्रिय-अप्रिय, सुख-दु:ख इत्यादि भावों से निरपेक्ष होता है। इसका विभाजन विषयों के आधार पर होता है। विषय पाँच होते हैं - रूप, रस, गंध, शब्द और स्पर्श।