What on earth are thoughts and mental notions?

Ru Ben's June 2 contemplative practice (vipaśyanā-caryā) log:

These days when I sit in meditation, in the process of subduing body and mind, I have used various methods—contemplative recollection of the Buddha (buddhānusmṛti), silently reciting the Heart Sutra, silently reciting the Buddha's name, reciting the Śūraṅgama mantra, contemplating the thirty-two bodily constituents, contemplating the arising, ceasing, and mutation of mental sense-objects (dharma-objects)—to make the mind focused and no longer restless and unsettled. It is like taming a wild horse: one needs to use various methods to find out what it likes, what it wants, and why it likes it, to identify the cause, and then resolve that cause; only then can the desires and thoughts in this regard be eliminated.  

Personally, I find that after sitting down, contemplating the arising, ceasing, and mutation of the thirty-two constituents of the body, one dharma at a time, is very effective. As soon as I begin to apply mental engagement (manaskāra) with "hair, body-hair, nails, teeth, skin," starting with "hair"…, the mind begins to quiet down. After contemplating through the thirty-two constituents roughly once, I then introspectively examine this mind that can feel, observe, and discriminate: what does it look like, where is it, what does it depend on and take as object, what is its scope of function, and how does it differ from mind consciousness?

During contemplative practice, as long as I maintain a single questioning doubt: "Who am I?", then repeatedly experience, one dharma at a time, within the physical body and mind consciousness, discerning each dharma's state and characteristics, scope of function, conditions, distinctions, and so on, then at some unknown moment it suddenly coincides with the dharma teachings I have studied. Then one understands that the intellectual understanding of learned knowledge and the feeling after contemplative experience are different, even though the conclusion is the same.  

Sometimes when wandering thoughts suddenly arise, I do not try to suppress them. My method is to contemplate the causes of these mental sense-objects surfacing, to contemplate their essence, their source, what they depend on and take as object. Later I discovered that I had attached a label to all of them: you, me, him. Then I measured them as right or wrong, true or false, good or bad, and following that came these emotions that could not be let go of—joy and anger, agitation, depression and discontent, anxiety and craving—like dust covering, oppressing, binding, and tying up the originally pure mind; truly a case of spinning a cocoon to bind oneself. It turns out these are nothing but mental sense-objects left over from past memories; they are not the mind, yet do not exist apart from the mind; they fundamentally have no self-nature—they are merely memory-names and concepts in one's own mind-field. Having resolved the mental sense-objects, I then came to know the essence, source, dependence, and object-support of the other four sense-objects—material sense-objects, sounds, and tangibles—as well.

 This is the true cause of the arising of wandering thoughts. In the beginning, one must repeatedly come to know and discern the mental sense-objects, and only then can one let go of the mind's grasping (upādāna); only after letting go can there be release and gathering in. The method of suppression cannot solve the root problem—it is like knowing only that something is so, but not knowing why it is so—and then wandering thoughts are hard to subdue.  

Next, before contemplative practice, one's hearing and reflection (śruta-cintā) must be mature; otherwise wisdom cannot arise, and one will not know how to contemplate and discern—there is śamatha but no wisdom of vipaśyanā. For example, every doctor has a certain direct perception (pratyakṣa) observation of the body's birth, mutation, aging, and death, yet the notion that the body is "mine" remains unchanged; there is no wisdom, and they do not know to seek the essence of life. So personally I feel that mature hearing and reflection before contemplative practice is the foundation. Then contemplate the mutual influence between the physical body and mind consciousness, and then deeply believe that every stirring of thought and mind has its retribution (vipāka), that all is self-made and self-received; then the mind grows more and more peaceful.  

Finally, rest the mind on the breath at the nostrils. Sometimes when the breath is faint, I only feel the entire physical body breathing, with no boundary between inside and outside the body. When meditative concentration is good, I feel body and mind in a state without self and without a master, gradually no longer having the concept of a body. Currently, in half-lotus posture I can basically hold for an hour without changing legs, and after rising from the seat I feel full of energy. However, when the legs become numb, swollen, and painful, mental strength weakens, and I need to change legs to continue.

After rising from the seat, I go out to move about and practice tai chi. I find it is the same as sitting meditation and contemplative practice: very quietly, very slowly, very easily I enter the state of contemplative practice, with body and mind in a state without self and without a master, the breath even; there is no one there—only arms and legs slowly moving through the air, only birdsong rising and falling in the empty stillness, only the formless, signless, nowhere-abiding mind aware—there is no one there.  

In daily life, I try to keep in mind the physical body of thirty-two constituents and its mental activity, not looking at the body as a whole, thus observing the body's impermanence and masterlessness. Currently I cannot yet form uninterrupted mental engagement (manaskāra).  

Assessment: All thoughts, ideas, and notions come from ignorance (avidyā), and ignorance has no source and no destination—it is a illusory dharma. Since wandering thoughts, ideas, and notions come from sourceless ignorance, there is no need to take them seriously; see through them and see them clearly, do not follow the arising and falling of wandering thoughts, remain suchness immovable, and gradually these ignorant thoughts will disappear on their own, and the mind will become pure and peaceful. Then contemplate the object-support again, luminously clear, and ignorance grows thin. Human ideas and notions come and go; even if you want to keep them, you cannot hold onto them; they are always shifting and changing, unable to be fixed. See through them, pay them no heed, do not move along with them, and the mind is naturally cool and refreshed.