As far as I know, noun without an article in front is normally used to mean something in general.
The use of ' a ' means referring to a single thing.
The use of ' the ' for the purpose of specifying the particular thing.
eg. Life is short, we'd better live to the fullest
![Smile [:)]](/emoticons/emotion-1.gif)
. We don't say a life or the life since it means the general life.