Is the external world perceived through the senses real or unreal? If real, what is its nature? If unreal, what then, is the reality? These are the questions often raised and discussed by the Indian philosophical systems. The Vijñānavāda school of Buddhism (also called the Yogācāra school) denies reality to the external world and considers it as ideas or states of the internal vijñāna (consciousness or mind), which alone is real. This vijñāna is the ālaya or abode of all impressions. Hence the name ‘ālaya-vijñāna.’ It is the potential mind similar to the ātman of other systems. However it is considered not as an unchanging substance, but as a stream of continuously changing states. Through proper culture it can gradually stop the arising of the undesirable mental states and develop into the ideal state of nirvāṇa (emancipation).