I am about to get a lot more technical than I should, but this question has gnawed at me for a while. I always hear about the Will of the Force. We are also told that the Force is an energy field created by living things and is communicated to individuals by midichlorians (thank you Qui-Gonn). However, the existance of a Will implies sentience, which should be quite impossible for an energy field. The best theory I've come up with (this is only a theory and by all means, I am willing to be disproved) is that the midichlorians are the ones with the sentience and that is communicated via a sort of hive mind, hence the "field". This is probably how the Force is manipulated as well.

I know that I'm going to get a few comments telling me to stop over thinking it but there you have it.