The Brain Determines the Strength of Conscious Function

What is the difference between the manas-vijnāna in dreams and the manas-vijnāna outside of dreams? During sleep, the circulation of qi and blood weakens, and consequently, the circulation within the brain also diminishes. The six consciousnesses rely on the brain’s subtle sense faculty (adhipati-indriya) for their arising and functioning. After the manas-vijnāna arises in a dream, due to issues with the subtle sense faculty, the functions of the mental consciousness become relatively weak. Consequently, the mental consciousness's discernment within the dream becomes unclear and imprecise, and memories formed are not firmly retained. If the manas (the seventh consciousness) perceives the dream as extremely important and finds it highly stimulating, the impression becomes profound, prompting the manas-vijnāna to deepen the memory. Upon waking, the mental consciousness can recall the dream vividly and clearly. 

Due to external forces causing brain injury leading to coma, the six consciousnesses disappear. After regaining consciousness, some individuals may experience amnesia. This occurs because the brain damage obstructs the functioning of the mental consciousness, causing its ability to integrate information to become disordered or weakened, resulting in an inability to recall people and events from a certain period. However, if the brain is subjected to strong stimulation, the mental consciousness may recover the memory, recalling past people and events. Memories from childhood and early youth are not firmly retained because the brain is not fully developed, leading to weak mental consciousness function and unstable memories. The mental consciousness of elderly people is generally weaker than in their youth, resulting in imprecise discernment, coarse thoughts, and what is commonly referred to as senility. 

Impaired circulation of qi and blood can damage the brain, causing a person to become foolish, dull-witted, or mentally impaired. Therefore, the six consciousnesses are dependently originated (paratantra-svabhāva); they are phenomena produced by causes and conditions (pratītyasamutpanna-dharma). They are utterly illusory and unreliable; the six consciousnesses are neither the self (ātman) nor belonging to the self (ātmiya). Within the intermediate state (antarābhava), the functions of the mental consciousness are even weaker because the intermediate state body is a temporary manifestation composed of coarse, inferior four elements, far inferior to the human body. This severely obstructs the functioning of the mental consciousness. Therefore, within the intermediate state, the mental activities of the manas predominate, and the mental consciousness cannot effectively regulate the manas. The inherent nature of the manas determines the destination of the next rebirth. Hence, the realization of fruition (phala) attained solely through the mental consciousness is like a fruit made of paper—fragile and insubstantial.