Saturday, 16 December 2006

Birthdays - Another superstition

Well today is my birthday, so I will keep this post short.

Now the origin of celebrating birthdays according to the Encyclopedia of Superstition was to draw up horoscopes, in those ancient times when we did not understand the universe much at all and over-ascribed causality and purpose to supposedly meaningful events such as one's birth.

Well I was born under the sign of Ophiucus, the constellation that lies in the zodiac (constellations that contain the Sun during the course of the year) between Scorpio and Sagittarius. Hang on a sec, this is not one of the 12 astrological constellations, astrologers would say I was a Sagittarian! This fact alone - that the 12 astrological signs do not map in amount to the 13 astronomical constellations should immediately tell you that something is seriously questionable about astrology - this process does not map onto any physical basis in the "heavens" in the first place. That is it is quite arbitrary to ignore varying constellation durations, equalise these durations, ignore the precession of the equinoxes and miss out one constellation entirely! Until this is answered, even speculating about a physical model of astrology is a waste of time, since unless one can explain all these alterations, in addition to which there are no other alteration analogies available in all the accepted scientific literature (typical simplified modelling works quite differently), there can simply be no physical basis. Enough said.

Yet many people believe in astrology, how so? A good question and one that can be tested and has been. There have been hundreds of studies done in astrology, by astrologers, cognitive psychologists and other scientists and when you look at these all together - in meta-studies - there is overwhelming evidence that there is nothing there! The type of meta-analysis done here is, in my opinion, a very good one - not done with filtering out studies based on "poor" or sub-standard methodologies - where disputes always arise about who decides these standards and how the filtering is done. In this case analysing the lot all together - without any of this filtering - still produces a big null! If there was some positive detectable outcome this would be shown by
  1. The effect size would be significantly different to zero
  2. If the distribution of the results are symmetrical around this value, then there is no publication bias (such as only publishing positive results)
  3. If the distribution of the results are asymmetrical, then there is publication bias and the average needs to altered to account for this
  4. As the sample size (say number of people in a study) goes up, these studies should tend closer to the average and so as one goes larger, those studies produce values closer to the mean.

In the case of astrology the results indicate (2) rather than (3), there is no publication bias and (4) is correct, larger sample size lead to results closer to the average. The only problem is (1) since the average effect size is zero! It does no matter whether you are testing individuals ability to recognise their own star chart, astrologers ability to match personality (defined on their terms) to star charts, astrologers ability to rate each other nor is their any difference between novice and experienced astrologers in performance! There is nothing there! I think this meta-analysis is an exemplar of what good meta-analysis should be like. (Search for Geoffrey Dean and astrology for more info, cant be bothered to add links, it's my birthday for goodness sake!).

Now Stephen Gould once said, in science, "fact" can only mean "confirmed to such a degree that it would be perverse to withhold provisional assent." I think it would be perverse, given the evidence confirmed to such a degree here, to say otherwise than it is a fact that astrology is rubbish! Yet people still believe, both before and after being presented with such arguments (better laid out usually) as here. And this is what really interests me.

Why do people believe in spite of the evidence - to prefer to believe based on faith rather than evidence and logic? It is the same process, although more easily discernible and testable, through which people hold religious beliefs. And this is useful. We can possibly learn more about faith-based reasoning by studying such processes as astrology and its kin, than by examining the root of such thinking in religion. Whatever the focus, one is gaining knowledge of faith-based reasoning and why some prefer it over evidence-based reasoning.

This all leads to my concluding thought for the day. Why am I interested in this and enough so to run a blog on this theme? Well it is all very well living in these times of relative plenty - whatever the current issues happening now and some are very grave, the truth we still are living in surprisingly pleasant times. My concern is what happens when the times change and things get really tough. If we have not enshrined single standards for everyone within our state's laws then it could be surprisingly easy for our society to be subverted by the tyranny of a majority driven by faith based reasoning, just a little history shows those results: communism, fascism, talibanism and in general extremist, authoritarian regimes whether theocratic or based on other ideologies. They need and thrive upon faith-based reasoning and this is a theme I will explore in future posts.

On that pleasant thought have a nice day!