Absence of what is the question? Absence of a person? Of a specific thing? Life? To create the absence of something, you need to have had or expect that something in the first place. For example if I was working on a piece where the director wanted an absence of humanity, I might use very quiet wind samples or an empty field against a location that would normally be very noisy, like a city shot. Basically between you and the director I would come up with a list of sounds that SHOULD be there - specific to whatever is absent, but WON'T thereby creating a sense of absence because they're missing. It may help to establish the sound of the thing in a previous scene, before taking it away - again based on discussions with the director.
Here's an example of a project I did: http://blip.tv/ottawa-horror/nightmare-1666924. (It won an Accolade "Best of Show" for Sound, so I don't feel I'm being to self-serving here, plus there are no legal issues sharing it!)
It's essentially a character in a nightmare, so we created an absence of "reality". For example the lack of any foley is intentional - it's absence makes you feel "wrong" - he SHOULD be making noise. At around the 5:00 mark, you'll notice that the city is completely devoid of any "human" atmospheres - no cars, trucks, or city sounds, just the wind and the weird voices. We purposely took things out to give the audience a subjective sense of "dream".
To sum up, for something to be "absent" in needs to have been "present" either in the movie or in the audiences perceptions.
And as FaderJockey said, this is something you REALLY need to discuss with your Director to make sure it matches his/her vision of the film.