Mind stream?
There is no such concept in Buddhism. Existence itself is fundamentally empty of such phenomenon. All is impermanence. The realization of this, is the liberation from the illusion of a self. You're suggesting a kind of
panpsychism, or
panentheism but these features are not essential to understanding or practicing Buddhism.
Nirvana is said to be identical with anatta (lit. non-self) and sunyata (emptiness). It is a state of ultimate freedom: freedom from sorrow, but also freedom from happiness. Nirvana is sometimes translated as "To be free from entangled roots," or "To escape from the woven web." In ancient Sanskrit, the three syllables (nir+var+na) have multiple meanings, as a noun it most commonly means "extinction" or "vanishing from sight". There's a verbal root "va", which means "to blow." With the prefic "nir" which changes the meaning to "down" or "out", it becomes the verbal root "nirva", "to cease to blow, to be blown out or extinguished" (like when a candle is blown out). It refers both to the act and the effect of blowing at something to put it out, but also the process and outcome of burning out, becoming extinguished. The particle Nir is a form of negation, meaning "without".
It represents transcendence from suffering, karma, and samsara, and is sought through the extinction of desire and individual consciousness.
Nirvana is also used synonymously with moksha (Sanskrit), also vimoksha, or vimutti (Pali), "release, deliverance from suffering". In the Pali-canon two kinds of vimutti are discerned:
- freedom of mind; it is the qualified freedom from suffering, attained through the practice of concentration meditation (samādhi). Vetter translates this as "release of the heart" which means conquering desire thereby attaining a desire-less state of living.
- freedom through understanding (prajña); it is the final release from suffering and the end of rebirth, attained through the practice of insight meditation (vipassanā).
Nirvana is associated with a meditative attainment, the 'Cessation of Perception/Ideation and Feeling' (sannavedayitanirodha), also known as the 'Attainment of Cessation' (nirodhasamapatti). However in Buddhism there are two types of nirvana, one in life, and one final nirvana upon death; The first nirvana that marks one who has attained complete release from desire and suffering but still has a body, and a second nirvana representing the fading away without remainder, a cessation of everything, giving it up, and relinquishing, or letting it go, without clinging to it. This is the final nirvana, or parinirvana at the moment of death, when there is no fuel left. The main distinction here is between the one who has extinguished the fires of passion/aversion/ignorance in life, and the final "blowing out" of all consciousness at the moment of death (which happens regardless of whether or not one has attained the first kind of nirvana).
Anatta means no abiding self or soul in any being, nor a permanent essence in any thing. This interpretation asserts that reality is of dependent origination, and that subjective perception is ultimately a delusion, a mirage (
marici). In Buddhist thought, this illusion must be overcome, through the realization of anatta, which is nirvana.
Sunyata is literally emptiness or nothingness, where all subject-object discrimination and dualities disappear, there is no conventional reality, and only the ultimate reality of emptiness. This refers to the notion that all things are empty of intrinsic existence (svabhava). Perceiving events in the mind and the senses without anything lying behind them. This is called emptiness because it's empty of the presuppositions we usually add to experience to make sense of it. All objects are empty of essence, or intrinsic nature, themselves being only conceptual existents or constructs. Nature is fundamentally empty of such distinctions. Such objects cannot be said to ultimately exist in any way. This is true down to the atomic level.
The Prajñāpāramitā sutras also use various metaphors to explain the ultimate nature of things as emptiness, stating that things are like "illusions" (
māyā) and "dreams" (
svapna). This sutra describes how all conditioned things are like a bubble, a shadow, like dew, or a flash of lightning. Though we perceive a world of concrete and discrete objects, these objects are "empty" of the identity imputed by their designated labels. In that sense, they are deceptive and like an illusion:
Form is emptiness, emptiness is form
Emptiness is not separate from form, form is not separate from emptiness
Whatever is form is emptiness, whatever is emptiness is form.
This is not too different from concepts found in the Tao Te Ching, or the Upanishads.
Since all things have the nature of lacking true existence or own being (
niḥsvabhāva), all things are mere conceptual constructs (
prajñaptimatra) because they are just impermanent collections of causes and conditions. Things seem to arise as objects, remain for a time and then subsequently perish, but they are fundamentally empty of any real essence. The realization of emptiness is a key understanding which allows one to reach liberation because it is nothing but the elimination of ignorance/passion/aversion. This emptiness is the absence of duality between perceiving subject and any perceived object.
The present moment is a combination of prior states of the universe, and the laws of nature. Bound by causality in such a way that any state is determined by its prior state. Karma then is not actually a system of retribution or morals, but rather a intricate network of causality. Since all things in the universe are in a state of constant flux, or entropy, rebirth can be said to be taking place constantly, every moment there is a constant change of states from one to the next. This doesn't have to encompass anything metaphysical or supernatural.
Nature itself exists in an all encompassing web of being, it exists in a state of impermanence. Moment to moment your cells, molecules, atoms, are always moving, always in a state of flux, of constant death and rebirth and renewal... and no where among this is there found any real "you", any real essence; we speak of a rock as a rock, and a chair as a chair, but these things are fundamentally empty of any essence, there is no real "chair", no chairy essence, just collections of matter, molecules, atoms, that exist in a state of entropy. In all this there is a continuity of nature, and this is fundamentally empty of any self, any essence.
This ultimately means there is no mind stream, no metaphysical soul. You can speak poetically of the continuity of nature possessing "soul", as an all encompassing being, but this concept like any other is fundamentally empty of any real essence.