There is a stronger relationship that many astrologers rely on (knowingly or not) - most developed countries have fixed school intake starting/end points for each year. So in the UK you can be fairly confident that people born in July/August are more like to be insular/solitary, less likely to take part in sports or social activities, and the opposite is true for people born in October/November, who are more likely to be leaders, sporty, socially dominant, etc.

If you want to be a critical thinker then you need to recognise that correlation does not imply causation.

Just look at about the millions of idiotic claims out there to see the horrible consequences of this logical fallacy.

"Sleeping with one's shoes on is strongly correlated with waking up with a headache.
Therefore, sleeping with one's shoes on causes headache"

Or

"The more people are taxed the more money they earn.
Therefore taxes make people money."

I'd give you some more serious examples if I could- but the fallacy is committed just about every day to support idiotic arguments.

He does mention how astrology is a complete empirical failure -- zero statistical significance of astrological predictions, and zero ability to predict when someone was born.

I doubt that JS Mill wrote much on statistical methods, but he was living long before it became easy to compute a variety of statistics. That aside, I note that another common astrological apologetic is

The stars incline; they do not compel. (Astra inclinant non necessitant.)

However, statistical testing enables one to test hypotheses of influences that incline without compelling, and as I'd mentioned, astrology fails miserably there.

I will concede that a common anti-astrology argument is rather bad -- it's the argument from weakness of gravitational forces and other such known effects of the planets. That is entirely correct about such forces, but astrologers can then claim that there is some completely unknown force that makes the planets and stars have the effects that they do.

Phil Plait at http://www.badastronomy.com had a good refutation of astrology on purely physical grounds, but I'm too lazy to look up the direct link.

The main thrust of his argument was that, given the relative sizes and distances of the planets from earth, there is no conceivable attribute that could cause the effects astrologers are claiming. No matter how you assign the 'astrological' effect either one body (eg the Sun) swamps any possible effect from the other bodies or everything is lost in the noise from all the smaller bodies.

That is entirely correct about such forces, but astrologers can then claim that there is some completely unknown force that makes the planets and stars have the effects that they do.

If they make an existence claim it's up to them to provide proof of the unknown force.

If they can't do that then weakness of gravity, etc wins.

Oh and the Mars effect looks like it's just data dredging (which is what we see in a lot of altmed 'studies').

His first three methods, and possibly the fourth, are the motivation for controlled-experiment protocols. A classic experiment is Francesco Redi's test of the hypothesis that flies are spontaneously generated from rotting meat. He kept flies from some meat with some gauze and allowed flies to reach some other meat, and he discovered that only the meat that flies could get to would produce more flies.

I will concede that a common anti-astrology argument is rather bad -- it's the argument from weakness of gravitational forces and other such known effects of the planets. That is entirely correct about such forces, but astrologers can then claim that there is some completely unknown force that makes the planets and stars have the effects that they do.

But one can test for astrological effects empirically, and for the most part, the result has been abysmal failure. The only reputable claim of evidence of astrological effects has been Michel Gauquelin's claims -- and (1) his claims are rather different from the more typical astrological claims and (2) his results are rather ambiguous.

Steve Bowen:

I'm sure I recall reading (and I will research this when time permits) that certain measurable character traits vary with season of birth, the theory being that oxytocin and serotonin levels etc vary with infant exposure to sunlight.

Which should be testable by comparing people born at roughly opposite latitudes at different times of the year.

There is also the possibility that the character traits difference has to do with their age when they started school with those born around late autumn tending to be the oldest in their class.

As for the relationship between ghosts and aliens, I think that's pretty much it for a lot of them (and the whole UFO nonsense does seem to have advanced our understanding of psychology somewhat (along with discovered some new atmospheric phenomena)).