I had the concept of dreams as being a string of unstable, disconnected perception that our minds try to understand by impressing our a priori conceptions upon it. We dream of something entirely senseless, and then turn it into a familiar object. That is why dreams are usually in familiar places, with familiar people. We aren't equipped to make sense of dreams so we use our conceptions from waking hours and try to fit them onto the senseless flow of dream perception.

So then the interpretation of dreams can be thought of as finding out why your mind applies these a priori conceptions to the somewhat random flow of raw dream.