[We were out with X at Y Restaurant] and her belief in astrology came up. I balked and said my faith doesn't support it. But she said, "Did you know the Three Wise Men were astrologers and based on the stars it signified a remarkable birth?"
What am I missing to retort this?
I'm not sure. But even bad math can sometimes get the right answer.
More technically, the men in Matthew's gospel are identified as "Magi," which in Greek has the connotation of "wise man," "seer," "interpreter of dreams", or "magician," and denotes an established class of men in Persia, to the east of Israel, or what we'd call Iran today. In the ancient world, new stars or comets or the like were commonly held to be portents of some great birth or death, and these guys interpreted it that way and showed up. You see that in the histories out of antiquity all the time. Does that mean the system of astrology (which may not be the same thing here) works as a whole? Again, I would here toss out my "bad math" line.
But more broadly, I'd point to this: astrology, like so many other systems of thought in the past and today, is a determinism. It is a system of thought that says our lives our determined by some circumstance beyond our control, but which controls us. Astrology, genetics, sexuality, your relationship with your parents, conditioned response, Marx's economic view of humanity – history is full of determinisms, as has been your own psychological field, and I'm sure there are determinisms being conjured out of the new neurological sciences you are watching closely. There's a point to be seen here: it is quite obvious that there are aspects of our lives that are beyond our control, and which determine huge amounts of our subsequent lives. Our families' personal and relational situations, our economic status, the genetic inheritance we receive with inherited possibilities for health and illness, cultural benefits and lack thereof; the list can go on and on. But do any of these fully determine who we are? The power of the claim is that it is one of your "Half Truths," that so entice people because they see some kind of truth in it ("life seems to be beyond my control"), but that it doesn't think things through enough to realize that it is only a limited truth or insight, and not an absolute one.
The Jewish and Christian inheritance gives one great gift to the rest of the world that is critical here: and that's the idea of freedom. There is an indeterminacy within human existence that cannot be accounted for, or entirely limited by, all its environmental circumstances. The Jewish-Christian view allows for the "both/and" here, acknowledging both the truth that our lives our influenced, bounded, and determined in a great variety of ways, but also still recognizing that ability toward freedom, choice, and self-determination. Some people absolutize freedom itself today, and we see that in contemporary politics. And some people keep using old and traditional determinisms like astrology, or conjure up new ones and claim that "This is all that we are." And a lot of people, not trained in the clear thinking of philosophy, just don't bother to do all the work to "finish the problem" and see where their half truth runs into problems. I suspect that there's a psychological motivator at work here, because people want their lives to make sense, and they are willing to settle for something that gives them a sense of what's going on, even if the answer they receive is that they are cogs in a machine that's beyond their control. (And, also attractively, determinisms excuse our behavior as beyond our control.) And they will also frequently have utterly incompatible ideas in their heads, because they haven't done the work to see where these ideas conflict and then have to be resolved or even discarded. So, for example, I'm sure that you can find no end of people who say they believe in astrology, but who also have a politics that asserts absolute freedom and choice.
As to astrology itself, a determinism built on the relative position of the starts and planets as influencing human life has certain problems. First, that it's somewhat arbitrary. Why the stars and the planets? Why not the relative positions of air molecules, or of passing birds, of nuclear-powered submarines, or of pieces of sheep dung that look like Golden Age Hollywood actors and actresses? No one bothers to say why these things are the things that determine all destiny. They're big and shiny and cool-looking, and we've been staring at them since humanity emerged, but that's about it. The stars give us a sense of the fullness of the cosmos, and so they have the "bigness" that might be attractive in making a determinism. Second, what is the mechanism of connection is between them and human life? No one seems to try to explain the medium by which the stars can have their effects: What kind of power is transmitted? How is it transmitted? Why do they have X effect on human beings? Do they do the same for aardvarks, etc? And what about how modern astronomy has let us know that for the stars farther away, we are not even actually seeing them where they are now, but where they were the 50,000 years ago that it took this bit of light to reach us? These are the serious questions of someone looking for serious answers. No one looking for cheap answers (much less anyone looking to swindle the gullible through offering cheap answers for a price) bothers with such questions. Third, it's too big and general of system. That is, astrology cannot ultimately cope with the diversity and complexity of human existence.
Augustine of Hippo was a believer in astrology in his 20s, although this eventually fell victim to his asking serious questions. His account in The Confessions (in Maria Boulding's 1999 translation: all the translations online affect "thee" and "thou" King James English, which drives me nuts) is a good way to look at this third problem with the idea of astrology, and why it is inadequate to a description of human life:
Book VII, Chapter 6, Section 8. It was some time since I had rejected the misleading divinations and impious ravings of astrologers. On this score too let your merciful dealings themselves sing praise to you from the innermost depths of my soul, O my God! In my obstinacy you took care of me by providing me with a friend: you it was, you and no other, for who else calls us back from our every death-dealing error but the Life that cannot die, the Wisdom who enlightens our needy minds but needs no borrowed light itself, the Wisdom who governs the whole world, even to the fluttering leaves on the trees? Obstinately indeed had I struggled against the shrewd old man, Vindicianus, and against Nebridius, a youth of wonderful insight. The former had declared with emphasis, the latter admittedly with more hesitation, but frequently, that the art of foretelling the future is bogus, that human guesswork is often lucky, and that when people talk a great deal many truths about future events are likely to be uttered, not because the speakers know but because they stumble upon them by not keeping their mouths shut. So you provided for me a friend who was keen to consult astrologers, but not well versed in their lore. Having sought answers from them out of curiosity, as I have indicated, he already knew a certain amount, which he had heard, he said, from his father. Little did he know how efficacious it was to prove in giving the lie to that superstition.
His name was Firminus. He had been educated in the liberal arts and was a well-spoken man, and since he regarded me as a dear friend he consulted me about certain of his business affairs of which he had high hopes, inquiring how I interpreted his birth horoscope, as they call it. Now I was already inclined toward Nebridius' view of the practice; however, I did not refuse to offer an interpretation or say what came into my mind, doubtful though I was; but I remarked that I was almost persuaded that divination was absurd and meaningless.
Then he told me that his father had been an avid student of books dealing with such matters, and had had a friend who was equally a devotee. As the two men collaborated in research and discussion they became more and more ardently enthusiastic for this nonsense. If even dumb animals in their households were due to produce young, these men would record the exact moments of birth and note the position of the stars at the time, on the pretext of collecting experimental data for what claimed to be a science. Firminus went on to say that he had heard his father tell how, when his mother was pregnant with him, Firminus, a certain slave-girl in the house of his father's friend was expecting a baby at the same time. This fact could not escape the girl's master, who took the utmost care to calculate even the whelping-times of his dogs. So while one man was observing and counting with meticulous precision the days, hours and smaller fractions of hours in his wife's case, the other was doing the same in respect of his maid-servant.
The two women gave birth simultaneously, forcing them to assign exactly the same horoscope, even in the finest detail, to both babies, the one to his son, the other to his slave. It happened like this. As the women went into labor the two friends sent word to each other to let each know what was happening at the other's house, and held messengers in readiness who would announce to each the birth of the child as soon as it occurred. It was easy for them to arrange for instantaneous announcement, since each was master in his own domain. So, Firminus related, the two sets of messengers were dispatched, and met at a point exactly halfway between the two houses, which meant that neither of the friends could assign a different position of the stars, or record any different moment of time. Yet Firminus was born in easy circumstances among his own relatives, and pursued quite a brilliant career in the world, making money and advancing in rank, while that slave-boy went on serving his masters, with no alleviation whatever of the yoke his status imposed on him. Firminus, who knew him, testified to the fact.
9. As soon as I heard this story, which, in view of the narrator's character, I believed, my obstinate resistance was completely overcome and dropped away. I attempted first of all to rescue Firminus himself from his curiosity about the occult by pointing out to him that if, after inspecting his birth horoscope, I had to make a prediction that accorded with the facts, I would have to say that I read in it that his parents were of excellent standing among his kinsfolk, that his family was a noble one in his home town, and that having been born a gentleman he would receive a good education in the liberal arts; whereas if the slave had consulted me about the indications of his birth horoscope—and his had been precisely the same—I would have to say, if my answer was to match reality, that what I saw in it was a family of the lowest class, a servile status, and all the rest of those very different conditions which marked off his lot from the other man's. The realization that after inspecting the same data I would either have to make divergent predictions in order to give a true answer, or else make the same prediction in the two cases and thereby speak falsely, was to me most certain evidence that when true predictions were offered by diviners who studied horoscopes, such things were the product of luck, not skill; but when false predictions were made, they resulted not from the practitioner's lack of skill, but from his luck letting him down.
10. Approaching the subject from this aspect and pondering these points, I now turned my attention to the case of twins. I hoped to attack and refute and make a laughing-stock of the demented people who make a living by astrology, and I wanted to make sure that none of them would be in a position to retort that either Firminus had lied to me or his father had lied to him. At the birth of twins, then, it usually happens that both are delivered from the womb with only a short interval of time between them; and however great the influence this space of time may be alleged to have in the course of nature, it cannot be measured by human observation and certainly cannot be registered in the charts which an astrologer will later study with a view to making a true forecast. And true it will not be, because anyone who had examined the one same birth horoscope that applied to Esau and Jacob would have been obliged to foretell the same fate for both of them, whereas in fact their destinies were different. The astrologer would therefore have been wrong; or, if he spoke truly and foretold different things for each, he would have done so on the basis of the same data. He could speak the truth only by chance, then, not by skill.
For in truth it is you, Lord, who are at work, you, the supremely just ruler of the universe, though those who consult astrologers and those who are consulted know it not. By your secret inspiration you make each inquirer hear what befits him, as your unfathomable judgment shall justly assess our souls' secret deserving. Let no human being challenge you, “What is this?” or “Why that?” Let him not ask; no, let him not ask, for he is but human.