What if I told you that there’s a 2,000-year-old divination practice which claims that the life and personality of some primates is defined by the movement of the moon, planets, and a few randomly defined constellations? You’d probably think I’m crazy, right? Well, allow me to introduce you to astrology.

Despite its millions of supporters and despite all the mainstream and niched attention it seems to get, astrology has zero scientific evidence to back it up. Sure, maybe you missed that flight when Mercury was retrograde, and maybe he does act like a Libra, but all that can be explained through much simpler ways that don’t involve constellations and planets.

Astrology is not real. It is falsifiable and falsified and your sign doesn’t mean anything. Let’s dive in.

How it’s supposed to work

Throughout its history, astrology has been regarded as a science, an art, and a form of divination magic. Today, it’s been strongly and repeatedly proven to be a pseudoscience with no working mechanism behind it — but let’s not get ahead of ourselves.

Astrology is the belief that the alignment of stars and planets affects every individual’s mood, personality, and environment and that it all depends on when the individual was born. Different variations and forms exist, but that’s the gist of it. In astrology, personalized horoscopes are printed by birth date and make vague predictions, generally about the love life, success, and health of people under the same horoscope sign. They also make daily, weekly, or long-term predictions about what people’s lives and relationships will be like.

But how does this work — how can the movement of planets have this impact? Why is the position of Venus or Saturn affect whether I’ll be bold and assertive or feeling blue for the next week?

Well… it doesn’t. There is no mechanism to explain how it could work, no force that can back it up, and, furthermore, no rational reason to split up the entire human population into 12 groups symbolized by randomly assigned constellations. No matter how you look at it (and people have tried), there’s no plausible mechanism that could work.

Constellations and the Zodiac

A constellation is a group of stars that forms an imaginary outline that seems to look like something. Most constellations represent an animal, an object, or a mythological hero. Twelve ancient constellations were assigned to the zodiac, with each representing a particular sign. These constellations were first described in Babylon, some 3,000 years ago. The Babylonian star catalogs entered Greek astronomy in the 4th century BC, circulating across different cultures.

Some constellations, including a few in the zodiac. Does this look like an Aquila to you? Is that a Capricorn, really?

There is no indication of why everyone born at the same time of year would be under the same influence. Renowned astrologer Elizabeth Teissier famously tried to explain that by saying “The sun ends up in the same place in the sky on the same date each year,” but that couldn’t be further from the truth — there’s a difference of about twenty-two thousand miles between Earth’s location on any specific date in two successive years. Plus, even if it did, it doesn’t explain anything.

Also, it’s important to consider the context of this: the zodiac signs are the result of Babylonian pattern-matching on the night sky. This doesn’t seem very reliable and indeed, other cultures had different constellations and treated the night sky differently.

In other words, what most people call astrology is essentially reinterpreted Babylonian sky observations.

But aside from it being based on old myths and nothing really tangible, does astrology actually work?

Testing astrology

Testing the validity of astrology isn’t exactly straightforward because astrologers themselves can’t agree on what it’s supposed to do.

Some practitioners claim that astrology is a science and that there is a mechanism behind it all but we just haven’t found it yet. However, despite several trials and experiments, astrology has never demonstrated its effectiveness scientifically and was refuted through various methods (more on that a bit later).

Other astrologers propose conventional causal agents such as electromagnetism and gravity. But the gravitational effect of constellations is completely negligible compared to even that of the moon, let alone the Earth — and the perceived magnetic field of other planets and constellations are far smaller than those produced by modern household appliances.

Is astrology a science?

Although astrology can seem like a science because it tries to explain something from the natural world, astrology doesn’t have a verifiable mechanism, and astrologers don’t have a critical approach towards their claims. Critically evaluating a hypothesis, testing it against a conflicting theory, and adjusting the theory based on existing evidence is essential in science — and astrology fails on all three accounts.

Therefore, astrology cannot be considered a science.

Other astrologers don’t try to explain a causal agent, simply saying that the field cannot be researched — essentially, they classify astrology as a form of divination, a supernatural force at work. Basically, magic.

Regardless of the general disbelief of scientists regarding astrology, there have been quite a few attempts to assess its effectiveness.

Astrology vs Science

It can be quite challenging to find new studies about astrology — and that’s because astrology has been disproven through and through, and there’s very little incentive to carry out additional studies. But the few existing ones are quite convincing.

The Carlson study

In 1985, Nature published a rather unusual study by a young physicist called Shawn Carlson. Carlson carried out what is widely regarded to be the most comprehensive test of astrologers’ abilities to extract information about their clients from the apparent positions of celestial objects as seen from the places and times of their clients’ births.

Carlson was very careful in designing the study, making sure that it fit both the requirements of the scientific and the astrology communities. He involved 28 astrologers from Europe and the US who were held in high esteem by their peers.

He also made sure that the study was double-blind — during the study, neither the participants nor the researchers know which participants belong in which group. Double-blind studies eliminate subjective biases from all sides involved.

The results were clear: the astrologers’ guesses were no better than chance — and even when the astrologers were very confident that they had made a match correctly, results were still no better than chance. Or, as Carson himself put it, astrologers “are wrong.”

Astrology only seems to work in bad studies

Not all studies are made equal, and if you look hard enough through the literature, you’ll come across some studies that seem to at least suggest that astrology might work. In 1979, Ivan Kelly from the University of Saskatchewan showed that the vast majority of studies conducted do not confirm astrological claims, and the few studies that are positive need additional clarification.

Then, 20 years later, Kelly returned with another study that also explained that astrology has no theoretical foundation to lie on.

Kelly participated in one more relevant study: for several decades, researchers tracked more than 2,000 people under the same zodiac sign — most of them born within minutes of each other. According to astrology, the subject should have had very similar traits, but this was not the case. Basically, the study participants had no notable similarities, outside what you’d expect from a random distribution.

A different study, from different authors, with an even larger sample size came up with similar results.

Astrology is a pseudoscience

There are several studies and reviews of studies and, as mentioned above, they all indicate the same thing: astrology is all smoke and mirrors. But in a particularly interesting study, University of Michigan’s Paul Thagard put forth an elegant argument, proposing a thorough criterion that separates science from pseudoscience — demonstrating that astrology definitely falls in the latter category.

So there’s no theoretical basis for astrology, no practical results, and yet sometimes it seems like astrologers get it right. Why is that?

Why astrology might seem like it “works”

Still, despite having no footing to stand on, no mechanism to explain it, and nothing more than ancient myths as its foundation, astrology seems to work, or so its supporters say. So how can that be?

Our brains are hardwired to look for patterns — even when such patterns might not exist.

The core approach of astrology is to give out vague, blanket statements, like “You will overcome an important challenge this week”. This strategy is used for “predicting” future events as well as assessing personality traits. But that doesn’t tell the whole story.

A reason why astrology can be perceived as believable is that our brains are hard-wired to look for patterns. Sometimes, when two unrelated or random events happen, our mind tries to see a connection — even when there’s no connection to be seen. In the case of astrology, a very similar effect pops up. This effect is called “subjective validation,” and it occurs when two unrelated or random events are perceived to be related because of a previous belief or expectancy, which “demands” a relationship. So you read a horoscope, it says that something will happen to you, and whenever something somewhat relevant happens, you attribute it to the horoscope you read previously.

This was brilliantly illustrated by a psychologist called Bertram Forer.

The Forer experiment

Forer gave a “unique” personality analysis to his students and asked them to rate how well it suits them, on a scale from 0 to 5. By now, you’ve probably guessed what happened — all the students received the same personality analysis, and all of them thought it suited them. Even better, Forer created personality analysis from various horoscopes.

“You have a great need for other people to like and admire you. You have a tendency to be critical of yourself. You have a great deal of unused capacity which you have not turned to your advantage. While you have some personality weaknesses, you are generally able to compensate for them. Disciplined and self-controlled outside, you tend to be worrisome and insecure inside. At times you have serious doubts as to whether you have made the right decision or done the right thing. You prefer a certain amount of change and variety and become dissatisfied when hemmed in by restrictions and limitations. You pride yourself as an independent thinker and do not accept others’ statements without satisfactory proof. You have found it unwise to be too frank in revealing yourself to others. At times you are extroverted, affable, sociable, while at other times you are introverted, wary, reserved. Some of your aspirations tend to be pretty unrealistic. Security is one of your major goals in life.”

The average rating that students gave this assessment was 4.26/5 — in other words, students found the assessment to be 85% accurate, even though they were all blanket statements.

Suckers

This type of blanket statements became known as Barnum statements, after P.T. Barnum, who used them in his performances, allegedly stating that “there’s a sucker born every minute.”

More evidence

A similar experiment was carried out, ironically, by astrologer Michael Gauquelin. Gauquelin offered free horoscopes to any reader of a Parisian newspaper, provided that they would give feedback on the accuracy of his supposedly “individual” analysis. As with Forer’s experiment, he sent out thousands of copies of the same horoscope to people of all astrological signs — 94% of readers replied that the reading was accurate and insightful.

To top it off, the horoscope he gave out was that of a local mass murderer, Dr. Petiot, who had admitted during his trial that he had killed 63 people.

Gauquelin set out to scientifically analyze astrology, and his results came out strongly against his profession.

This being said, horoscopes can (sometimes) make people feel better

With all this being said, astrology isn’t necessarily all bad.

Although astrology has no scientific backing, no consistency, and no reproducibility, astrology doesn’t really have the negative impact of some of the other pseudosciences such as anti-vaxxing or homeopathy. In a sense, astrology is a benign pseudoscience — and in some instances, it can even have a minor positive effect on people’s mental state thanks to the placebo effect.

Many people believe in astrology, and when they read their horoscope and follow its advice, they feel better. This doesn’t have anything to do with astrology itself, but rather with the way people perceive it. Astrology is glorifying, it gives a sense of communion with the cosmos, and it promises to bring a bit of magic into your day-to-day life.

But at the end of the day, it’s not real. There’s a sucker born every minute — and most of them are looking for magic.