I never really get the purpose of divination
It is not so difficult. Just open your favorite dictionary. The purpose of divination is to foresee future events.
Now, if foreseeing future events is not important to you, then, according to your own logic, nothing has a purpose anyway, because the fulfillment of a present purpose resides necessarily in the future, and has to be foreseen in order to be achieved.
having been brought up in what would be classified as a western culture.
Any culture, Western or not, is all about foreseeing the future. We are all driven by purposes, which are to be fulfilled in the future, and such fulfillment has to be foreseen in order to be achieved.
Physical sciences are all about foreseeing, or predicting events. If an event is not predictable, it is not reputed as scientifically explained.
However, overpowered by preconceptions, someone may say that this or that future event cannot be predicted. Actually, there is no scientific evidence showing that an event cannot be predicted. Even Heisenberg's uncertainty principle points to a limitation of physical measuring instruments in relation to quantum objects, not to a limitation of knowledge in general, or of mind to that effect.
On the other hand, since there is nothing which is not dependent on mind, it follows that there is nothing outside the scope of knowledge, which means that there is no future event which cannot be predicted.
Therefore, it is just natural that many cultures have developed divination methods, which may be more or less accurate. However, there is no scientific basis to outrightly reject them.
Specially, as far as ”Western” or European and Mediterranean cultures are concerned, they have traditionally relied on divination. Egyptians relied on the oracle of Amun at the Siwa Oasis. The Greeks relied on the oracles and seers, and specially on their sibyls such as the Delphic, Cumaean, and many others. The Etruscans and Romans had their augurs and auspices. The Celtic peoples of Western Europe relied on their Senae for prophecies, healing, and weather making. Nordic people also relied on divination, which might be or not related to the runes. And the list goes on endlessly.
But maybe what you refer as the ”Western culture” you have been brought up in is actually the Jewish-Christian psychotic culture which, just like the no less psychotic Islamic culture, strictly forbids any kind of divinations, oracles, fortune-telling, astrology, omens, and so forth.
Indeed, the book of Leviticus (19:26), referring to oracles and astrology, explicitly commands that ”You shall not act on the basis of omens or lucky hours”. Christianity from early times considered divination a ”pagan” practice, and forbade it under capital punishment, which was extensively applied in so many witch hunts, the canonical laws forbidding divination continuing to this day. To Islam divination is ”Haram”, which means absolutely sinful and forbidden.
This Abrahamic (Jewish, Christian, and Muslim) proscription of divination is a necessary result of their belief in an omnipotent god, and their rejection of karma. One's future, they believe, is not dependent on one's actions, but only and strictly on their omnipotent god's will.
Therefore, looks like your ”Western culture” has nothing at all of ”Western”, but is just the usual Abrahamic (Jewish, Christian, and then Muslim) deranged, fundamentalist monomania, which has been forced through violence and deceit on Western (and other) peoples for the last 2000 years.
I know divination is very popular in the Chinese culture.
Not only in Chinese culture, but everywhere it has not been suppressed by Abrahamic (Jewish, Christian and Muslim) fundamentalism. For instance, divination is an important feature of Tibetan culture (just read Milarepa's life), of Mongolian culture with the anklebone divination (shagai), and virtually of every single other shamanic culture in Asia, of many African cultures such as the Yoruba of West Africa and the Serer of Senegal, and was a fundamental aspect of Aztec, Maya, Olmec, and every other civilization of Ancient Mexico and Central America, including the use of entheogenic substances such as the peyotl, until, of course, the wholesale destruction of such cultures by Jewish-Christian barbarians (and Muslim barbarians in Africa and Asia as well).
Anyhow I find it strange to have a practice that people would consult divination and let the result of divination erect the course of their life.
This is because you have been possessed by the fundamentalistic virus of Abrahamic ideologies, which rejects the dependent arising of actions and experiences; otherwise you would find just natural that one erects the course of one's life on the basis of foreseeing the results of one's actions, or on dependent arising, which is what divination is all about.
However, to the Abrahamically brainwashed person, only the irrational will of their omnipotent ”god” counts, and therefore they do not care about acting in accordance with dependent arising, or about taking into consideration the results of their actions, but only about showing absolute submission and subservience to the cruel, gruesome, chimeric creature invented by their own scriptures, which they call ”God”.
I guess the reason I feel it strange is that where do one stop asking then if one start to rely on the results of divination to determine the course of one life.
Why should one stop asking about the results of one's actions in the first place? The only reason why one should foolishly dismiss such essential knowledge is a fanatical, superstitious belief in an omnipotent god, coupled with the resultant rejection of the dependent arising of actions and their results.
Therefore, until one becomes a buddha, and is thus able to directly see all phenomena of the past present, and future, one should constantly rely on dependent arising, and therefore on divination, in order to understand the results of one's and others' each and every action.
Or how do one rate what is important or not important enough to ask?
Study the lamrim, for instance, and you will figure out very easily what is important or not to ask to a reliable oracle. For instance, which actions will ensure my own and others' happiness in this life and in all future lives; which actions will ensure the freedom from samsara for myself and others; and which actions will ensure full enlightenment for myself and others.
In a way would not it become like an attachment and also putting the responsibility onto someone else to make the decision.
Since divination, and reliance on it, implies recognition of the dependent arising of actions and their results, and thus that one's experiences are the infallible result of one's own actions, there is no way that it could cause one could put the responsibility for one's decisions onto someone else; rather the opposite, it will only enhance one's understanding of dependent arising, and one's sense of responsibility.
On the other hand, reliance on an omnipotent god which is the sole cause of everything, even therefore of evil and of one's own evil choices, is the sure way to abandon responsibility for one's own actions, which is precisely what we see in Judaism, Christianity, and Islam, where the most horrendous actions, such as those perpetrated by their ”prophets”, are justified as the fulfillment of ”God's” commands, thus putting the responsibility for their crimes onto such an imaginary ”God”.
And again, denying divination on materialistic grounds implies also rejection of the dependent arising of actions and their effects, whereby one will only blame others for one's own faults.
Anyway it's interesting to read about the practice nonetheless.
Yes, and then the next step is to make an effort to understand dependent arising, and the impossibility of an omnipotent god, and then to assume full responsibility for one's own actions, thus rejecting the sinister shadow of the Abrahamic maniac monotheism, which for more than 2000 years has distorted, corrupted, and vandalized Western culture and other cultures.
