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Cognitive Biases

Astrology

Astrology claims to infer personality or fate from celestial positions, but reliable predictive evidence is lacking. Vague horoscopes can feel personal because readers connect broad statements with their own concerns and remember apparent successes more readily than failures.

THE IDEA

ASTROLOGY

Astrology claims that the positions of celestial bodies can reveal or influence human personality and fate. This amazing idea has existed for thousands of years. I get conflicting explanations today, however, when I ask believers if these celestial bodies cause our actions or simply foretell what is going to happen without actively causing any of it. Either way, it’s fascinating to imagine such a spooky connection with stars and planets. There were times in our past when astrology made sense to even the most educated and enlightened people in many societies. It was viewed as respectable science and a productive means of gathering information. But we have learned a lot about both space and human psychology since the days of ancient Babylon. For example, scientists figured out some time ago that the locations of stars and planets show no detectable or measurable impact on the personality and fates of individuals. Really, it’s true; Mars and Saturn have nothing to do with whether or not you will get that promotion at work or marry the ideal spouse one day. Venus has no bearing on how high-school cheerleading tryouts will turn out for you.

Astrology presents us with yet another opportunity to pause and reflect on the profound weirdness of humankind. On one hand, we have come so far. People once looked up at the night sky and saw gods and animals in the stars. They imagined that they cared about us, influenced us, and whispered secrets. Later, we would walk on the Moon, land robots on other worlds, peer deep into the universe and time itself with powerful telescopes, and even contemplate the end of this universe. Yet for all the brilliance we have shown, many millions of us still look up and see planets and stars that know the intimate details of personal lives.

It is important to be absolutely clear about one thing: Astrology is not scientific. It is not evidence based. It has never been proven that astrology is able to describe our lives or predict the future, so I don’t think it can. But don’t take my word for it. Make up your own mind.

Beyond the fact that it’s unproven, there are two key points that crush the case for astrology. First, consider how people might have come to attach personal meaning to celestial patterns. That history does not settle whether a modern prediction works; the prediction still needs evidence. Astrology’s earliest beginnings are lost forever in prehistory. But it’s not difficult to imagine early humans injecting personal meaning into the visible stars, planets, and the Moon. Who can blame them? They knew nothing of astronomy, so the beauty and mystery painted across a typical night sky could easily have sparked magical thinking. These lights above me must mean something. How could they not? Perhaps I am connected to them. Maybe I should fear them, revere them, or use them to understand the meaning of my life. They must be the key to understanding this confusing world I live in. They are telling me something.

History’s earliest mentions of astrology come from the Sumerian and Babylonian cultures, stretching back three thousand to four thousand years ago. Astrology in one form or another has been hugely influential throughout history and is in some ways the ancestor of astronomy. Try not to read too much into that, however. It’s like saying that primate grooming—the practice of picking and eating lice and ticks off your buddy’s hide—is the ancestor of haircuts and shaving. True, perhaps, but not a pastime we necessarily need to hold onto today. In most societies and for many centuries, everyone from queens and kings to generals and doctors did little without consulting an astrologer. Even in modern times, some of the world’s most powerful leaders have been influenced by astrological beliefs.35 But don’t allow yourself to be overly impressed by age and influence. Popularity and some degree of historical impact are not enough to save astrology.

Recognizing patterns in the sky does not establish a reliable connection with an individual’s personality or fate. That requires predictions tested against outcomes, with failures counted alongside successes. If a modern-day astrologer claims to rely on some book or source documents, ask for titles. Ask where it or they came from. Ask for early sources that do not simply describe astrology but also explain its origins and how it functions in a way that makes sense. Follow the trail back far enough, however, and it always leads to a familiar place: human imagination. Astrology is layer upon layer of made-up stuff. This is not science. Its predictive powers do not exist. The feeling that a horoscope fits your life may tell us more about human innerspace than about a planet’s influence.

Astrology’s second fundamental problem is that nobody seems to know how it is supposed to work. “It just does,” is the most common explanation I hear from believers. Astrology may have been important to the development of early astronomy, and it may have even been useful in keeping time and developing early agriculture. However, as it is practiced and believed in today, it’s pure pseudoscience. There is no underlying theory that explains it, no body of knowledge that supports it, and no set of experiments that confirm it. I know this because I have asked professional astrologers. I listened with an open mind, and when told that my status as a Libra meant that one thing or another would happen to me and that I was inclined to think and feel this way or that, I asked how they know this. “Because the stars say so,” is not an answer, of course. Why do the stars say this? How do the stars say this? These are the simple questions that need to be answered, but never are. I suspect that many believers imagine there must be some vast collection of data stored in the vaults of a giant astrology archive somewhere that serves as the source material for all the horoscopes written today. Or maybe they think there is some centralized supreme council of astrologers that generates the calculations all astrologers base their work on. But there are none of these things.

A final point that everyone should be aware of is that horoscopes are popular and work well for so many people because most of them are written in ways that allow virtually everyone and anyone to recognize something that feels unique and special to them. A good horoscope writer can craft fifty words or so that will feel personal and specific to the individual reading or hearing it—no matter who that individual is. If something is known about the person in advance and the horoscope can be personalized, even better. It’s like psychics with their cold readings. Focus on challenges and concerns common to most of us, and those who are predisposed to believe will think it must apply to them in some special way. As far as predicting things about the future, two things help that along: vague predictions and confirmation bias. A prediction like: “You will enjoy financial gain this week,” could mean winning the lottery, finding $5 on a sidewalk, or nothing more than getting your weekly paycheck. For most believers, confirmation bias will ensure that astrology’s relatively few successful predictions are remembered and its many failures forgotten.

When someone tells me how awesome astrology is, I don’t argue. I just ask a few questions and pay close attention to the answers. Try it. Ask how the stars and planets go about influencing or predicting the course of our lives. What is the force behind this? How does it work? Is it gravity? If so, how does that proposal account for the masses and distances involved, and what specific result would test it? Ask them why it is that people born in October have different personalities and talents than people born in December. Don’t let them ramble on about all the ways in which they are different; you want to know why they are different. Asking these important questions and not allowing yourself to be sidetracked by hollow answers are key to becoming a good skeptic and staying focused on reality.

When to use it

  • When considering whether to make a major life decision based on zodiac advice, pause and evaluate the source's credibility.

  • Before trusting a horoscope, ask yourself if the prediction is vague enough to fit any outcome.

  • When someone claims astrology is scientific, challenge them to explain the mechanism and provide replicable evidence.

FROM THEORY TO EVERYDAY LIFE

In practice

01

Horoscope vagueness

A horoscope predicts 'You will enjoy financial gain this week,' which could be interpreted as winning the lottery, finding $5, or receiving a paycheck. This vagueness allows nearly anyone to find personal relevance.

02

Cold reading parallel

Astrology works like psychic cold reading: it focuses on common human concerns and applies general statements that seem specific but actually fit many people.

✳

A MOMENT TO REFLECT

Put it to work.

  1. Think of a time you felt a horoscope or astrological prediction was accurate. Could the same words apply to many other people or situations?

  2. If astrology were real, what physical mechanism would explain how distant planets affect individual personalities? Is there any testable hypothesis?

  3. How does confirmation bias help astrology seem convincing despite its many failures?

Connected ideas

Another lens can bring the same problem into focus.

References

  1. Footnote 35 (no further details given in text) — Unknown

CONTINUE THE CONVERSATION

Source texts

  • Think (Guy P. Harrison)
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