How Astrology is Fake

Astrology is the belief that the positions of stars and planets affect people’s lives and can predict the future. Despite astrology’s ancient origins and widespread popularity, there is no scientific evidence to support its validity. Here’s a detailed look at why astrology should not be taken seriously:

The Origins of Astrology Are Not Scientific

Astrology originated over 2000 years ago and was intertwined with astronomy, mythology, and early mathematics. However, astrology was developed long before the scientific method or our modern understanding of astronomy and physics. Ancient astrologers had no way to scientifically study and validate their ideas about how celestial bodies influence human affairs.

Astrology Relies on Arbitrary Divisions of Star Signs

The zodiac signs used in Western astrology represent 12 equal slices of the sky starting from the vernal equinox. But the constellations the signs are named after are different sizes and shapes, and the boundaries between signs are arbitrary. For example, the stars that make up the constellation Aquarius actually spill over into Pisces. The zodiac has also shifted over the last 2000+ years due to the Earth’s precession, so the dates the signs fall on are no longer aligned with the actual constellations.

People Are Not Defined by Their Sun Sign Alone

Astrological birth charts are based on the day, time, and place you were born. Astrologers claim your birth chart reveals your personality traits, future, and compatibility with others. However, astrology only looks at the placement of the sun at your time of birth, which is called your sun sign. But people’s personalities are far too complex to be defined by just one factor. Astrology fails to take into account genetics, upbringing, experiences, and cognitive biases that shape who we are.

Astrological Predictions Are Vague and Open to Interpretation

Horoscopes make vague predictions about love, money, and other aspects of life that could apply to just about anyone. For example, a prediction that “new opportunities are coming your way soon” is very broad. Astrologers exploit a psychological phenomenon called the Barnum effect, which causes people to believe personalized information applies specifically to them, even when it’s very general. Good science requires precise, falsifiable predictions. Astrology fails to meet this criteria.

Studies Find No Evidence Astrology Works

When astrology has been rigorously scientifically tested, it has consistently failed to demonstrate any predictive power or ability to accurately match personality traits to astrological signs. A review of over 3000 scientific studies conclusively found no evidence astrology can be used to predict anything meaningful about people’s lives, personalities, future, or compatibility with others.[1] There is no reputable scientific evidence that the positions and motions of stars and planets can influence human affairs and personality.

Cognitive Biases Explain Why People Believe in Astrology

Although astrology has been debunked by science, surveys show between 25-30% of people in the US and Europe believe in astrology today.[2] Cognitive biases help explain this continued belief despite lack of evidence. Confirmation bias leads people to notice and remember events that match their belief in astrology while discounting those that don’t. The Barnum effect causes people to believe vague statements apply specifically to them. People are also more likely to believe claims that align with their worldview and desired outcomes.

Conclusion: Astrology is Pseudoscience, Not Science

While astrology may be ancient and culturally significant, it is not rooted in science or scientific investigation. It relies on arbitrary divisions in the sky, vague predictions, and cognitive biases that cause people to remember confirming evidence while ignoring disconfirming evidence. After centuries of investigation, there continues to be no scientific foundation for astrological claims. At best, astrology is a pseudoscience that provides entertainment. But at worst, it can cause people to make misguided life decisions based on false predictions. While many believe in astrology today, it should not be taken any more seriously than any other unfounded supernatural claim.


[1] Carlson, Shawn. “A double-blind test of astrology, Nature, vol 318, 1985, pp. 419-425.

[2] National Science Board. Science and Engineering Indicators, Chapter 7: Science and Technology: Public Attitudes and Understanding. National Science Foundation, 2018.

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