I find my self unusually busy right now. I so am serving up a short, light posting this time.
Consciousness became a word in English in the 1500s in its Latin form, conscius. It meant ‘knowing with’ or ‘having joint or common knowledge with another’. But the most common use was in the Latin phrase conscius sibi, or ‘knowing with oneself’. This phrase was used with the figurative meaning of ‘knowing that one knows’. This etymology explains why there are two very different uses of consciousness an individual one and a group one. Class consciousness is in effect ‘joint knowledge with others of class’ and comes from conscius. Whereas Locke’s definition is ‘the perception of what passes in a man’s own mind’ and comes from conscius sibi. It is used to mean knowing, percipient, aware, cognizant in non-technical English.
Today we find among the various reasons for consciousness is the sharing or mutual availability of information between different parts of the brain. In that sense, the etymology is ironically quite apt. Scientifically, the word is used to describe a very distinct physical process in the brain which has other reasons as well is sharing within the brain.
The Latin word conscientia would translate as ‘shared knowledge’ too, but in it’s English-Latin use it had the sense of a witness having knowledge of the deeds of someone else. When it became the English word ‘conscience’ it took on the meaning of our moral witness to our own acts.