Avidya is explained in different ways or on different levels within different Buddhist teachings or traditions. On the most fundamental level, it is ignorance or misunderstanding of the nature of reality; [a] more specifically about the nature of not-Self and dependent origination doctrines. Avidya is not lack of information, states Peter Harvey, but a "more deep seated misperception of reality". Gethin calls Avidya as 'positive misconception', not mere absence of knowledge. It is a key concept in Buddhism, wherein Avidya about the nature of reality, rather than sin, is considered the basic root of Dukkha. Removal of this Avidya leads to overcoming of Dukkha.
In other contexts, Avidya includes not knowing or not understanding the nature of phenomena as impermanent, the Four Noble Truths, other Buddhist doctrines, or the path to end suffering. Sonam Rinchen states Avidya in the context of the twelve links, that "[Ignorance] is the opposite of the understanding that the person or other phenomena lack intrinsic existence. Those who are affected by this ignorance create actions which precipitate them into further worldly existence." Not understanding the Four Noble Truths, or its implications, is also Avidya.
Bhikkhu Bodhi states that Avidya is an important part of the Theravada Abhidharma teachings about dependent arising about conditions that sustain the wheel of birth and death. One such condition is the karmic formations that arise from ignorance. In other words, states Bodhi, ignorance (avijja) obscures "perception of the true nature of things just as a cataract obscures perception of visible objects". In the Suttanta literature, this ignorance refers to the non-knowledge of the Four Noble Truths. In the Abhidharma literature, in addition to the Four Noble Truths, it is the non-knowledge of one's 'past pre-natal lives' and 'post-mortem future lives' and of dependent arising.
