Why is there no naturalistic description of astrology, that is, a description of astrology in terms of scientific materialism? Is it because there is a prior assumption that all aspects of this field can be dismissed on the grounds that the mechanism used to explain astrology does not fit with current scientific paradigms? But what if there were things being described by astrological systems that were compatible with modern scientific thought? What if there were something under the hood of the social phenomena of astrology that warranted investigation?
The prevailing tone of the modern scientific community is essentially combative - ideas gain credence by surviving the remorseless attacks of their opponents in journals, conferences or in the news. Certain systems - including but in no way restricted to astrology - seem to be excluded from consideration simply because the force of opposition would be too great. But shouldn't all matters be legitimate subjects for experimentation, research and theory formation?
I can see at least two elements of astrology which might warrant a scientific treatment (by which I do not mean a pugnacious sceptical dismissal - there are no shortage of these!)
Firstly, astrology as a noise system; a means for individuals to influence their actions without recourse to logic and sense; people with a more poetic bent might even say a chance to commune with fate. There are a variety of these noise systems in common use throughout the world - the I Ching, for instance, or tarot readings - and it seems clear even from a casual examination that there are genuine psychological processes being harnessed by these devices. It is insufficient to dismiss them simply because they are presented in a fanciful metaphysical wrapper: allowing noise to influence one's cogitations becomes meaningful. It seems to me that there is something worth investigating here (although it would take the dedicated agnosticism of a scholar of comparative religion to conduct a reasonable inquiry).
Secondly, why has no-one investigated the inherent claim of astrology that the time of year that one is born can affect one's personality? This is far from a fanciful claim (although the usual justifications provided by astrologers will struggle to fit a naturalistic perspective, of course). Consider that plants, for instance, grow into very different forms according to the temperature, light, altitude and other factors of their life history, and some reptiles such as crocodiles produce different gender offspring according to the temperature of incubation. It is certainly possible that similar factors might apply in human growth, and even if there were no biological basis, it could still have a psychological reality - a person could develop markedly different perspectives according to whether their birthday was in the Summer or the Winter, for instance. It is not impossible that a Capricorn (whose birthday celebration occurs in darker, colder months) might have measurable psychological differences from a Taurus (whose birthday is in warmer, brighter months), but no-one to my knowledge has actually checked.
The scientific community rarely if ever investigates such things because firstly, there's no funding for it, and secondly, scientists often fear their credibility would be harmed by investigating something which by enforced consensus is excluded from rational consideration. It is this unwillingness to explore all the avenues of exploration available to us - the myopic capacity for prior assumptions to weigh more heavily than direct observation - that leaves me highly sceptical of any claim that our modern scientific knowledge is even a remotely complete description of the universe.
Astrology is an integral part of modern culture, a symbolic language which is used by its practitioners to communicate abstract ideas about identity and behaviour (whatever the questionable nature of the foundations of that language), and a noise system which people use to disrupt their routines and create strange attractors in their lives. That it is usually presented in fanciful, superstitious terms should have no bearing on whether or not it qualifies as a subject for scientific investigation. The fact that anything might not qualify for unprejudiced examination should perhaps make us seriously question how we currently conduct science.