In the Shurangama Sutra, the Buddha starts off by saying that people who undertake spiritual cultivation but fail to realize ultimate enlightenment all fail because they don’t understand 2 fundamentals roots – the 2 different types of mind. They only think that there is 1 type of mind – their thoughts – and they rely exclusively on this type of mind. And so they end up mistaken and confused in their meditation and cultivation:

“Ānanda, what are the two fundamentals? 1. The first is the mind that is the basis of death and rebirth and that has continued since time without beginning. This mind is dependent on perceived objects, 38 and it is this mind that you and all beings make use of and that each of you consider to be your own nature. “ 2. The second fundamental is full awakening, which also has no beginning; it is the original and pure essence of nirvana. 39 It is the original understanding, 40 the real nature of consciousness. All conditioned phenomena arise from it, and yet it is among those phenomena that beings lose track of it. They have lost track of this fundamental understanding though it is active in them all day long, and because they remain unaware of it, they make the mistake of entering the various destinies.

Now, using the example of his fist, the Buddha asks Ananda, “What do you see it with?” Ananda replies, “With his eyes”.

So the Buddha goes, “So you see it with your eyes, but what do you take to be your mind, that was aware of it all?”

Ānanda said, “The Thus-Come One has just now been asking me about my mind’s location, and my mind is what I have been using to determine where it might be. My mind is that which has the capability of making such determinations.” The Buddha exclaimed, “Ānanda! That is not your mind!” Startled, Ānanda stood up, placed his palms together, and said to the Buddha, “If that is not my mind, what is it?” The Buddha said to Ānanda, “It is merely your mental processes that assign false and illusory attributes to the world of perceived objects. 42 These processes delude you about your true nature and have caused you, since time without beginning and in your present life, to mistake a burglar for your own child — to lose touch with your own original, everlasting mind — and thus you are bound to the cycle of death and rebirth.”

In other words, we mistake our thoughts to be our mind. But they are merely mental processes – they are mental objects that arise and cease within our mind, but not the Mind itself. Don’t mistake mental processes to be the Mind itself.

So now, Ananda is bewildered, because Ananda was so intelligent – he thought that everything that he did was with his mind:

If this activity of comprehending is not the mind, then I have no mind , and I am the same as a clod of earth or a piece of wood, because nothing exists apart from my mind’s awareness and its knowledge. Why does the Thus-Come One say that this is not my mind? Now I am genuinely alarmed and frightened; neither I nor anyone else here in the great assembly is free of doubt. I only hope that the Thus-Come One, with great compassion for us, will instruct all those among us who are not yet awake.”

Ananda is now thinking that if his intellectual processes of comprehending things is not the mind – then he has no mind! But is this true? No, it is not true. A lot of Buddhists think that there is no mind, but as we shall see, the Buddha does not say this at all – in fact, the Buddha says that the Mind definitely is a reality:

From the Lion’s Seat he reached out and circled his hand on the crown of Ānanda’s head, saying to him, “The Thus-Come One has often explained that all phenomena that come into being are nothing more than manifestations of the mind. All things that are subject to the principle of cause and effect — from the largest world to the smallest mote of dust — come into being because of the mind. If we examine the fundamental nature of each thing in the world, Ānanda, down to even the smallest wisps of grass, we will see that all have reality. Even space has a name and attributes. Given that, how could the clear wondrous, pure mind — the mind that truly understands and is the basic nature of all mental states — itself lack reality? “But if, as you insist, that which makes distinctions and is aware of them, which knows and understands them is indeed the mind, then that mind would necessarily have its own essential nature independent of its involvement with objects — with visible objects, sounds, odors, flavors, and objects of touch. Yet now, as you listen to my Dharma, it is due to sounds that you can distinguish my meaning. Even if you were to withdraw into a state of quietude in which all seeing, hearing, awareness of tastes, and tactile awareness ceased, you still would be making distinctions among the shadowy objects of cognition in your mind.

Here, the Buddha is teaching us how to tell whether something is really our Mind or not – if something really is our Mind, then it would be totally independent, not needing to rely upon anything. A real mind would have its own inherent existence – it would have a complete nature totally apart from any objects of sense.

What does this mean? Usually, we only know the things in our everyday world through our senses. So this type of knowing is dependent upon our senses. For example, to hear something, air vibrations (sound) has to hit our ears and we know that there’s sound – and our mind then knows the meaning of the sound. But the Buddha is saying here that that’s not a true type of knowing, that’s not our True Mind there because it is dependent upon sensory data.

Right now, the Buddha tells us to perform a thought experiment. Suppose you quieten down all your senses (say by sitting still in a quiet room with your eyes closed) – so now there’s no sensory stimuli impinging upon you through your body’s sense gates – all the senses become temporarily inactive:

Your eyes are closed – so there’s no visual stimulation

It’s a quiet room – so no sounds are impinging upon your hearing

You are sitting still – so the body is not moving – so after a while, you feel no sensations

You’re not eating anything – so no tastebuds are being activated

There are no odors in the room – so your sense of smell isn’t being activated either

So all your 5 senses (the 5 consciousnesses) are now inactive. BUT still, your intellectual processes (the 6th consciousness) is still active – you are still playing around in your mind with “shadows” of sense objects, which are thoughts/memories. They are called shadows of sense objects because it’s not a direct perception through our senses, but rather a memory of what we have perceived before through our senses. So these intellectual processes are still dependent upon thoughts – so that still is not your real mind!

“I am not demanding that you just accept that this distinction-making capacity is not the mind. But: Examine your mind in minute detail to determine if a distinction-making capacity exists INDEPENDENT of its perceived objects of awareness. That would truly be your mind.

If, on the other hand, your distinction-making capacity does NOT have an essential nature apart from its perceived objects, then it too would be a perceived object — a shadowy mental object. Perceived objects are not permanent, and when that mind ceased to exist such that it had no more reality than a turtle with fur or a hare with horns, then your Dharma-body would cease to exist along with it. Then who would be left to practice and to perfect patience with the state of mind in which no mental objects arise?” At that point Ānanda and the others in the great assembly were utterly dumbfounded. They had nothing to say.

This means that IF:

Your mind is dependent upon thoughts (a perceived mental object) AND Thoughts are impermanent – they arise and cease

THEN when the thoughts ceased, then your mind too would cease. So you and your mind would also die each time a thought died out – you would be annihilated upon the cessation of a thought. Then there’d be no point in spiritual cultivation because you would’ve been annihilated into oblivion. BUT you do not die whenever a thought dies because you are aware of thoughts AND you are aware of the space between thoughts – you are still aware when there are no thoughts, just after a thought ends and before the next one begins. Chan/Zen Buddhism uses this principle.

The Buddha concludes the 1st Chapter of the Shurangama Sutra with a summary to Ananda and a promise to reveal the True Mind, the Buddha Nature:

The Buddha said to Ānanda, “The reason why so many practitioners in the world do not succeed in putting an end to outflows and becoming Arhats — though they may have passed through all nine of the successive stages of samādhi 44 — is that they are attached to distorted mental processes that come into being and then cease to be, and they mistake these processes for what is real. That is why, even though you have become quite learned, you have not become a sage.”

Here, the Buddha is saying don’t mistake your thinking to be your real mind. Ananda, that’s why you are very intelligent but have not opened enlightenment yet – because you have confused your thoughts to be who you really are.

Thereupon the Buddha said to Ānanda, “I now will raise for all of you a great Dharma-banner so that all beings in all ten directions can gain access to what is wondrous, subtle, and hidden 48 — the pure and luminous mind that understands — and so that they can open their clear-seeing eyes.”

Source of the excerpts: A New Translation Buddhist Text Translation Society. The Śūraṅgama Sūtra With Excerpts from the Commentary by the Venerable Master Hsüan Hua (Kindle Locations 1160-1248).