Bhavanga-sota: and Bhavanga-citta: The first term may tentatively be rendered as the ‘undercurrent forming the condition of being, or existence’, and the second as ‘subconsciousness’, though, as will be evident from the following, it differs in several respects from the usage of that term in Western psychology. Bhavanga bhava-anga, which, in the canonical works, is mentioned twice or thrice in the Patthāna, is explained in the Abhidhamma commentaries as the foundation or condition kārana of existence bhava, as the sine, qua of life, having the nature of a process, lit. a flux or stream sota. Herein, since time immemorial, all contacts and experiences are, as it were, stored up, or better said, are functioning, but concealed as such to full consciousness, from where however they occasionally emerge as subconscious phenomena and approach the threshold of full consciousness, or crossing it become fully conscious. This so-called ‘subconscious life-stream’ or undercurrent of life is that by which might be explained the ability of memory, paranormal psychic phenomena, mental and physical growth, kamma and rebirth. etc. An alternative rendering is ‘life-continuum’.
It should be noted that bhavanga-citta is a kamma-resultant state of consciousness vipāka, and that, in birth as a human or in higher forms of existence, it is always the result of good, or advantageous kamma kusala-kamma-vipāka, though in varying degrees of strength see: patisandhi, end of the article. The same holds true for rebirth consciousness patisandhi and death consciousness cuti, which are only particular manifestations of subconsciousness. In Vis.M XIV it is said:
As soon as rebirth-consciousness in the embryo at the time of conception has ceased, there arises a similar subconsciousness with exactly the same object, following immediately upon rebirth-consciousness and being the result of this or that kamma intentional action done in a former birth and remembered there at the moment before death. And again a further similar state of subconsciousness arises. Now, as long as no other consciousness arises to interrupt the continuity of the life-stream, so long the life-stream, like the flow of a river, rises in the same way again and again, even during dreamless sleep and at other times. In this way one has to understand the continuous arising of those states of consciousness in the life-stream. Cf. viññāna-kicca. For more details, see: Fund. 11. App..