Can I use FaceTime on my Macbook without having an iPhone?

I do not have an iPhone, so therefore do not have the FaceTime app. However, recently I have purchased an Apple Macbook Pro which has a FaceTime app. I've made an apple ID log in but every time I try and log into the app on my Mac it says unknown error and does not let me use the app. Is there a reason for this?

HELP!