I'm reading a reading, since every written work is a reading of some event or some idea, an imposed understanding of it which I then impose my own understanding on. If the author is not different in each instance of writing as is Foucault's argument, then at least the reader is most likely different in every reading instance. I am a different person with more experiences and probably a different set of ideas in mind as I read this book that I read previously, and I will be different if I read it again after some time.