Why astrology fell out of favour: geocentric v heliocentric theories

I’d like to talk about the difference between the geocentric and heliocentric theories and the role these played in astrology falling out of favour.

I’ll start by explaining the geocentric theory.

The geocentric theory puts Earth at the centre of the universe with the Sun and all the other planets revolving around the Earth. We of course now know that this is incorrect but, for a long period of time, this is what was believed to be true.

Whereas the heliocentric theory puts the Sun at the centre of the universe with the Earth and all the other planets revolving around the Sun. We now know that this is correct and we’ve known this for quite some time.

The problem is that astrology is based on the geocentric theory and the geocentric theory has been disapproved. But this doesn’t mean that astrology itself has been disapproved. We need to understand that it is because astrology is based on our perspective from Earth it is as though the Sun and all the planets are revolving around us. The same way that we believe Mercury turns retrograde, even though it really doesn’t. It’s because from our perspective on Earth it looks like it does. And this is what we care about.

I’ll give a bit of background to the geocentric theory.

The geocentric theory was the astronomical model of the universe in Europe for about 1,400 years leading up to the 16th century. It’s accredited to Ptolemy in his scientific text Almagest. Almagest was written in about 150AD and was considered the authoritative text on astronomy.

Ptolemy’s system drew on many previous theories that viewed Earth as a stationary centre of the universe. And this explanation stood for nearly 1,500 years and was bolstered by its acceptance of the Catholic Church.

Ptolemy was a Greek mathematician, astrologer and astronomer. He played a very significant role in the development of western astrology. He was the most respected astronomer of his time and is the author of the book Tetrabiblos, which is also known as the Book of Stars.

In this 4-part book, Ptolemy laid the foundations of western astrology. Under Ptolemy the planets, houses, and signs of the zodiac were first explained in great detail. This explanation hasn’t really changed much to this day.

I read this book a couple of years ago and didn’t find it to be the easiest read. It wasn’t particularly well structured but I certainly recognised the astrology I practice today.

Ptolemy sourced the information for this book from all the old texts at the famed library of Alexandria in Egypt. This library is considered the greatest in the world because it stored alot of the ancient knowledge that was still available us. Ptolemy laid out all the complete theories from ancient Egypt, Sumeria and Greek Hellenistic sources in this book.

Ptolemy’s book was considered the astrology bible for thousands of years. The book covered meanings of planets, signs, houses, aspects, and forecasting techniques such as primaries, directions, transits and eclipses. It basically covered everything!

But Ptolemy wasn’t responsible for creating the astrological techniques in his book Tetrabiblos. He instead was responsible for organising the information already available to demonstrate that astrology is based on logical principles.

Ptolemy’s book Tetrabiblos was used as a textbook in European universities during the Renaissance and into the 17th century.

Now Ptolemy’s book was written from a geocentric perspective, which of course became disapproved. And this was a major contributing factor to astrology losing credibility and falling out of favour.

Let’s now talk about the heliocentric theory

The heliocentric theory is the astronomical model developed by the Polish monk Nicolaus Copernicus.

The heliocentric theory put the Sun motionless at the centre of the universe with the Earth and other planets moving around the Sun in circular paths. This model displaced the geocentric model, which had been around and believed for centuries.

This discovery of the helioentric theory is often regarded as the launchpad to modern astronomy and the Scientific Revolution.

The impact of this discovery meant that the understanding of where and how the celestial bodies moved and related to each other changed.

The positions of the Sun and Earth never changed, and neither did the placements of the planets from the perspective of Earth (and that’s what we care about). But the acceptance that the Sun was the centre of the universe still had a significant impact on astrology. This is because astrology is based on a geocentric perspective, which has now been disapproved.

Copernicus shared his heliocentric theory with colleagues sometime before 1514 but he didn’t publish it until 1543, shortly before his death. From what I understand this was because he was too scared to publish this theory any earlier because it was such a major game changer.

Copernicus, in his heliocentric theory, more accurately described the length of the solar year while maintaining a mathematically ordered universe. He introduced some innovations in his heliocentric theory. One of those innovations was that the centre of the universe is near the Sun and that the Sun is stationary. Another innovation was that the Earth and other planets revolved around the Sun and in a particular order. The retrograde motion of the planets is also explained by the Earth’s motion (because it’s about our perspective).

These innovations don’t actually change the way we practice astrology, but this seems to have been missed at the time and has had a flow on effect to this day.

This is because the Copernicus heliocentric theory disapproved the Ptolemy geocentric theory. And the discovery that the Sun was the centre of the universe, and not the Earth, was used to discredit astrology.

Ptolemy’s maths and astrological meanings were still accurate and the ephemeris also remained 100% accurate when used with the Copernicus heliocentric theory and Kepler’s planetary laws. And there was also no difference when using Ptolemy’s theory to create and interpret charts. But none of this seemed to matter anymore.

By the mid-17th century astrology was struggling to maintain its respected position (because it was very respected) and Ptolemy’s book Tetrabiblos (the Book of Stars) started to draw stigmatisation. Astrology was gradually removed from university curriculum and a division also developed between astronomy and astrology, which still exists to this day. The intellectual standing of astrology and its credibility collapsed around the end of the 17th century.

But the birth chart is a map of the heavens at the moment of birth from the perspective of Earth. It’s as though you’ve come out of your mother’s womb with a camera and pointed it straight up at the heavens and taken a photo. You’ve captured a moment in time from your perspective and this forms your birth chart.

This matches the geocentric perspective. And this perspective means that Ptolemy’s astrological interpretations remain accurate. Because of this, Ptolemy’s work continues to provide the foundation for the astrology we practice today.

There’s a quote from a book called the History of Magic and Experimental Science that I wanted to share with you. The quote is from Lynn Thorndike who was an American historian of medieval science and alchemy.

“Only the opponents of astrology appear to have remained ignorant of the Tetrabiblos, continuing to make criticisms of the art which do not apply to Ptolemy’s presentation of it. ”

— Lynn Thorndike, History of Magic and Experimental Science

I think the quote clearly expresses the credibility of astrology as presented by Ptolemy, and it doesn’t really matter that the geocentric perspective was disapproved on an astronomical level.

We need to understand the difference between the geocentric and heliocentric theories to reinforce that it’s not astrology that’s been discredited but the geocentric theory from an astronomical perspective. What we care about is our perspective of the universe from our place on earth. This just happens to be a geocentric perspective but we’re not saying this is how the universe works. We’re saying this is our perspective.

So there you have it. But this is just one reason why astrology fell out of favour. I’ll talk about more in future blogs.