A friend of mine posted a link to a description of why astrological star sign may not be what you think it is. The basic story is that the sun is no longer in the same place at the same time as when the astrological signs were decided. According to the newspapers I’m a Cancer, but astronomically (note the spelling) I’m a Gemini. I kind of wish I was born in early December so I could tell people my sign is Ophiuchus.
However, this precession of the signs does not necessarily mean that astrology is complete nonsense. One can imagine a world in which astrology really did work, despite the fact that the signs don’t match up anymore. It’s not hard. In fact I’ll do it right now.
It’s not hard to imagine that the time of year of one’s birth actually did affect one’s behaviour. Maybe our gestation period was more heavily influenced by ambient temperature, such that a developing embryo’s body chemistry was altered in specific and predictable ways. Isn’t there some species of reptile in which whether you become a boy or a girl depends on the temperature at which your egg develops? That’s what I’m talking about here. Even less crazy would be that a child’s first few months of development influence their behaviour. You might imagine a person born in December would be tougher than someone born in May because of various environmental things. I think there have even been proper studies on this kind of thing. Early childhood psychology and the like.
People would notice this kind of predictor. Except instead of noticing that the changes in behaviour are correlated with seasons, they notice that they’re correlated with the position of the sun at birth. These are really pretty much the same thing, and it seems like seasons would be an easier connection, but hey, everybody loves astronomy, right? So, instead of saying “babies raised in the first month of winter tend to be tough and have a high threshold for cold” (or whatever) they say “people who were born under Capricorn (Dec 23 to Jan 19) tend to…” etc.
And this system works. The people who have worked it out have just made a mistake in assuming that correlation equals causation (which it does not). But that doesn’t really matter since their mistake takes many lifetimes to become obvious, and by that point astrologers have stopped bothering to check if the Sun is in the same place it’s been in for the last hundred years. Another simple mistake.
But before you know it, the Sun has moved quite a lot, and the constellations don’t match up very well anymore, just as we see today. The seasons that caused this whole mess, on the other hand, are still right where they were before. People born in the first month of winter are still tough and cold (or whatever), and that still matches the description of Capricorn even though the Sun isn’t in Capricorn anymore. The system still works, we just have an outdated naming scheme.
So the claim that astrology is complete rubbish because the names of the signs don’t match up with the sun anymore is fallacious. You might as well claim that modern electronics can’t possibly work because current actually flows the other way. Unfortunate naming conventions don’t invalidate the thing they describe.
However, all of this is not to say that we live in a world where astrology is true. There are, I’m sure, dozens of other reasons why your newspaper horoscope can’t possibly be true, but I’m not going to address them here. The point is, astrology may be nonsense, but it’s not necessarily a priori nonsense.