The source for the "store house consciousness" idea?
The issue is actually one that is represented in one of the later Abhidharma Scriptures, the pali Kathavatthu.
In that Scripture there is a discussion in the form of questions and answers or argument points in which the problem of continuity comes up. Within classical Buddhism you have a series of moments which are experienced as subject and object.
It is like one of those ancient Greek paradoxes. If you create karma in one moment how was it carried forward from moment to moment? Or more pertinently, from incarnation to incarnation when there is a discontinuity.
The issue also came up in the meditation situation of cessation in the 8th level of jnana or dhyana. If you are truly in that state mental activity has come to a stop. So, if you have no mental activity, what is it that starts you up to consciousness again?
There was all sorts of efforts to deal with this between the 1st century B.C.E. and the 2nd century of the common era.
It seems that in the middle of the 2nd to the middle of the 3rd century CE two major sutras that were going to be associated with the Yogacara took form. It is the Samdhinirmocana Sutra with which we associate the official the inauguration of the concept of the ground consciousness to be
⁃ a receptacle of karma,
⁃ the place where it is held,
⁃ and the place from which it restarts up at as your foundation
below the 7th ego centralizing consciousness and your classical 6 consciousnesses.
But it's a little more complicated than that with investigation.
What people don't understand generally is that there were several texts called the Yogacarabhumi that have survived the vicissitudes of time. There is at least 4 or 5 that I have read about. 2 of the earlier ones are not Mahayana at all.
Originally the word ‘Yogacara’ only means what it reads as, ‘practitioner’ or ‘master’ ‘of yoga’. It is even used in the Lotus Sutra as the way of identifying a female Yogi. What was going on was that there was lots of groups wrestling with these problems, and many of them were practicing what you could call yoga ,which is really just a way of saying that someone is very serious about Buddhist mindfulness meditation, and they really focus on that, rather than, let say, cognitive analysis and verbal discussion.
It is one of those words that dissolves right in front of you as you look at it because Buddhism is all about mindfulness - and mindfulness is the core of whatever you would call yoga.
Now the book that we might humorously call the Mahayana ‘Official Yogacara Yogacarabhumi’, is actually a collection of 5 books.
The 1st section, sometimes called the Vastu Bhumi, is actually 17 sections - each relating to progress on the yoga path within Buddhism. The 15th, 16th and 17th and 18th have to do with the Sravaka path, the Pratyekabuddha path, the Bodhisattva Path and the 2 degrees of Nirvana, with and without remains.
The other sections on the path are technical discussions of different aspects of practice, so they aren't really sequential as far as progress up the path in the sense the last 5 are, even though most of them need to be covered before you get to the others or make progress to the others.
What is really important is the Sravakabhumi which is actually a text of a Sravaka group working outside the Mahayana. And it was incorporated into the Yogacarabhumi because of the philosophy of the “Encyclopedia” we call the Yogacarabhumi. That was and inclusive practice philosophy that once that a bodhisattva learned all of this foundational material and understood the early bhumis within practice - they simply didn't enter into the success of those early levels because they were going on to Buddhahood.
Needless to say the bodhisattva section is called the Bodhisattvabhumi! And like the Sravakabhumi presents a complete path, one which would be in practice one that incorporates the practices of the Sravakabhumi in its initial 2 of 5 “stages of meditation”. [And I'll just insert here that the 10 bodhisattva bhumi begin in the 3rd stage of meditation accomplishment called “seeing” and are completed according to some systems in the 4th stage called “meditation”, with the 5th stage being Buddhahood.]
So what this encyclopedia was trying to do was to be comprehensive as well as presenting a progressive development of Buddhist thought in that era.
What it also means is that the earlier parts of it were written in a way that were not Yogacara in the classical sense of Asanga and Vasubandhu. They represented intermediate ways of thinking about the ground consciousness that were the progressive ways of thinking about the ground consciousness that evolved from thinking about it as simply a seething mass of karma seeds in the background all the way up to the notion that it was a continuum consciousness in the unconscious depths of the mind.
What scholars are coming to a consensus about is that the Samdhinirmocana was written right in the middle of the decades in which the Yogacarabhumi was being assembled and written into being one continuous work.
It is in the 2nd through 5th commentarial sections of the Yogacarabhumi of 17 which are actually commentaries on the material in the 1st section, (about the 17 stages), that you actually have the word alayavijnana used in its most developed sense.
In those sections it is actually somewhat more developed in meaning than even in the Samdhinirmocana!
It is in retrospect, when people understand words in their modern or more developed meaning when reading or writing about older texts where those words had different meanings the IMPRESSION you get is one of a synthetic unitary philosophy embracing texts whose authors actually wouldn't have understood the modern sense at all.
And I believe this was part of the warning that you are being given. Often as sutras are carried forward by scribes and translators through the centuries words “clarifying ” the meaning of that sutra so as to updated to the latest understanding of those words are inserted but not in the sense of footnotes but well-meaning “adjustments”.
You must understand the tremendous devotion and heartfelt allegiance that these scribes and translators felt. It was a world before global communication. With so many people speaking and so few written records of what they said being possible to produce in a preindustrial society you really had to build up reverence for those text you wanted to be bothered to be written down and carried forward. Part of this was a a system of almost deifying respect by which you made sacred text you approved of and considered text you disagreed with fallen Angels. It was rather more human and fluid than that.
I have just discovered the wonder of what is often considered Chinese apocrypha. But the truth is all the Mahayana could be considered Apocrypha from a conservative Nikaya point of view.
I have found it more joyful to consider all a wonderful ongoing of parts struggling conversation to express the ground Buddha nature that is and within all of us but not a thing that you can put your finger on. What a challenge for both scholarship, meditation and love.