Is astrology science or pseudoscience?

THERE is a tendency in modern society to confuse astrology and astronomy, or worse yet, to consider one a legitimate alternative to the other. Although both arose from the wonders of the night sky, from stars to comets, planets, the Sun and the Moon, astronomy had a practical motivation. Knowledge of motions of these orbs made it possible to predict and plan for certain significant events, such as the changing of the seasons and planting of crops.

Many ancient astronomers, however, believed that “harmonies” or “synchronicities” exist between celestial configurations and human activities. They thought that celestial objects of the night sky exerted a special power over humans, particularly in foretelling the course of their life. Thus, along with the practical came the whimsical and the spiritual—astrology.

Astrology is a superstition that has no scientific basis. Its roots can be traced at least as far back as the Mesopotamian civilisation of the third millennium B.C. Today, astrology remains a popular delusion. It has trickled down to everyone, and people now find it routinely in newspapers and magazines.

Using medieval methodologies, astrologers generated a set of rules to make vague auguries and portents of a person's future and explain events on Earth. A diagram of the heavens called the horoscope is one of the tools of their trade. The horoscope shows the position of the Sun, planets and the Moon relative to the twelve constellations of the zodiac as they were thousands of years ago. Since then, change in the orientation of the Earth's rotational axis due to precession shifted the position of the ecliptic—path of the Sun against the background of stars. Consequently, the location of the constellations in the sky changed. They no longer correspond with the constellations in the horoscope.

As an example, astrologically I am an Aquarius because the Sun is believed to have been located in that sign at the moment of my birth. But that was thousands of years ago. In the year I was born the Sun was in Capricorn, not in Aquarius.

Astrologers divided up the year equally, ignoring variations in the size of the constellations. Since Virgo is huge, they chopped some of its sky and added it along with bits of Scorpio to the tiny Libra to bring it up to size. Astronomers call it “equal-opportunity swindling.”

There are currently thirteen zodiacal constellations, not twelve. Astrologers have ignored the thirteenth one, Ophiuchus, because they believe that this constellation was invented by the astronomers to bedevil them.

Unfortunately, people put their trust on the predictions and advices offered by the astrologers without demanding proof or verification. By doing so, they are not gaining any real knowledge. Instead, their blind faith on the prophecies shows a lack of understanding of what science is and of the distinction between scientific theory and faith-based convictions. Many careful tests have shown that, despite their extraordinary claims, astrologers really can't predict anything.

Astrologers sometimes argue that astrology is based on statistics and may not, therefore, be accurate for an individual. If their claim is true, then there should be a correlation between astrological lore and the different signs under which a person is born. Scientists have made serious attempts to test this hypothesis, but no correlation has ever been found.

Scientific disciplines based on hypothesis but with no consistent body of supporting evidence are called pseudoscience. Astrology is one of them. The difference between science and pseudoscience is the difference between objective reality and subjective impressions. Pseudoscience misrepresents real scientific discovery and contributes to anti-intellectual attitudes. It replaces exploration and discovery with mysticism and magic. Astrologers vehemently deny this and steadfastly resist any attempts to tamper with the veracity of astrology.

Scientists play intellectual games that have certain rules that need to be followed. They accept conclusions that can be verified by repeated observations or experiments, or by making predictions that can be tested. Astrology fails to meet these criteria.

Put simply, the tenets of astrology provide ample evidence of its absurdity. Effects of astrology do not exist in the Universe.

The writer is Professor of Physics at Fordham University, New York.