The Types and Forms of Solitary Consciousness (mano-vijñāna-eka-citta)

When the mind consciousness engages in thought activity on its own, not together with the five sense consciousnesses, that is the solitary mental consciousness. For example, when we are contemplating a Buddhist teaching or a principle, or engaging in meditative reflection, or recollecting, or daydreaming, or dwelling on matters on our mind, and so forth—all these various thought activities are the distracted solitary mental consciousness. Another example: in meditation, when one knows that various meditative states have appeared in one's own mind, and discerns what kind of state this is, what significance it has, and what its content is, various feelings can arise in the mind, and various thought activities appear. This is the solitary mental consciousness in meditation; its discerning activity does not occur together with the five sense consciousnesses. There is also the solitary mental consciousness in dreams—the activities we engage in while dreaming, discerning all kinds of dream scenes; these are all activities of the mind consciousness alone. For these activities to appear, many conditions must be present and complete; if even one condition is lacking, the solitary mental consciousness cannot manifest. When the solitary mental consciousness does not manifest, we cannot carry out these activities of deliberation, discernment, analysis, planning, and contemplative practice (vipaśyanā-caryā)—all of these activities simply cease to exist.