Consciousness is a quality of the mind generally regarded to comprise qualities such as subjectivity, self-awareness, sentience, sapience, and the ability to perceive the relationship between oneself and one's environment. It is a subject of much research in philosophy of mind, psychology, neuroscience, and cognitive science.
Some philosophers divide consciousness into phenomenal consciousness, which is experience itself, and access consciousness, which is the processing of the things in experience [1] Phenomenal consciousness is the state of being conscious, such as when we say "I am conscious." Access consciousness is being conscious of something in relation to abstract concepts, such as when we say "I am conscious of these words." Various forms of access consciousness include awareness, self-awareness, conscience, stream of consciousness, Husserl's phenomenology, and intentionality. The concept of phenomenal consciousness is closely related to the concept of qualia.
An understanding of necessary preconditions for consciousness in the human brain may allow us to address important ethical questions. For instance, to what extent are non-human animals conscious? At what point in fetal development does consciousness begin? Can machines achieve conscious states? [2] Are todays autonome and intelligent machines already conscious? These issues are of great interest to those concerned with the ethical treatment of other beings, be they animals, fetuses, or, in the future, machines. [3]
In common parlance, consciousness denotes being awake and responsive to one's environment; this contrasts with being asleep or being in a coma. The term 'level of consciousness' denotes how consciousness seems to vary during anesthesia and during various states of mind, such as day dreaming, lucid dreaming, imagining, etc. Nonconsciousness exists when consciousness is not present. There is speculation, mostly among religious groups, that consciousness may exist after death or before birth.
for more info to here is link to the wikipedia where there are lots of other links
Consciousness - Wikipedia
