Muggles' Guide to Harry Potter/Magic/Divination

Overview
Divination is presented as the ability to predict the future. While it is taught as a subject at Hogwarts, there are very few wizards or witches who can actually predict the future. As a subject, it is an elective, taught in years three, four, and five; those with sufficiently high O.W.L. marks in the course can then go on to N.E.W.T.-level study in years 6 and 7.

Extended Description
From watching the antics of the Divination teacher Professor Trelawney, one rapidly gets the impression that divination in the Wizarding world is no more a science than fortune-telling in the Muggle world. Formalized as it is, with its textbooks laying out instructions for tea leaf reading, palmistry, crystal balls, and dream interpretation, it still seems to be as deeply buried in nonsensical mysticism as any gypsy fortune-teller on a Muggle fairground.

The alternate Divination teacher, Firenze, seems to be more interested in teaching the methods of Centaur divination, and emphasizing that not all things can be determined completely. We should note in passing that, while it is never stated that we are seeing the results of Divination, the Centaur comments regarding astronomy in Harry Potter and the Philosopher's Stone are almost certainly the result of Divination. Firenze speaks of this sort of interpretation of the heavens, and how it differs from Trelawney's, in his Divination classes.

Analysis
We must be careful to separate Divination from Prophecy. Divination can be taught; Prophecy is apparently a rare gift, inborn and apparently uncontrollable. It would appear that prophets quite often fall into Divination as a career: Professor Trelawney does produce, in the span of seventeen years, two completely valid predictions. This seems to be completely separate from her teachings in Divination, and in fact she does not seem to remember having made either Prophecy.

It is particularly interesting that Divination can be taught and tested, but does not seem to involve any particular magic. We can see quite clearly, as Hermione does, that what Professor Trelawney is doing is little more than a fraud; she is using all the non-magical tricks that Muggle fortune-tellers use, including the foggy and mystical pronouncements. Yet she seems to be teaching out of approved textbooks, and there is evidently some testable technique involved, because there is an OWL exam (and presumably a NEWT exam as well) covering the subject. One wonders whether the purpose of the course is to codify a set of fraudulent techniques, and if so, for what reason. The adult reader also may wonder why Divination classes seem to be designed to hoodwink the students, rather than teaching them the methods by which they may deceive others. Two possibilities come to mind, however. First, if Trelawney knows she is a fraud, it is possible that only those students who show an ability to play along with the fraud are accepted into the advanced, NEWT-level practitioner classes; the initial three years of classes may simply be an elaborate familiarization and testing platform. Alternately, if Trelawney truly believes in the power of divination as she practices it, it's possible that she is teaching the methods and simply expecting that the ones she teaches will similarly believe in their own powers. Again, the three years of classes preceding NEWT exams would be primarily for testing, in this case retaining only those who were gullible enough to become convinced of the validity of the methods they were being exposed to.

It is possible that the published techniques are meant only to improve the sensitivity of the mind, and are not meant to be taken seriously. It is possible that the purpose of teaching Divination is simply to make it more likely that the apprentice Seer, assuming the inborn ability, would actually improve his or her chances of producing a true Prophecy. If this is the case, then it is somewhat unusual that Trelawney herself seems to be so serious in her techniques. It is possible that she herself does not know that she is a true Seer; the two times we have seen her making a real Prophecy, she has been unable to remember doing so. We do not know how common this trait is in Prophecy.

For discussion of prophecies as opposed to Divination, please see that article.

Questions

 * 1) What is the method of reading tea leaves? How is it meant to work?
 * 2) What is the meaning of the Centaur comment that Mars is bright, in Harry Potter and the Philosopher's Stone?