Question: Does astrology - the practice of interpreting celestial body positions as causally or correlationally linked to human personality, behavior, and fate - have predictive or explanatory validity?
Nature of consensus: Full consensus within the natural and behavioral sciences that astrology lacks empirical validity as a predictive or causal system. No comparable consensus exists among historians of science, philosophers of science, or scholars of religion and culture, who address astrology on different grounds and toward different questions.
Astronomers find no known physical mechanism by which planetary positions at the moment of birth could produce the specific effects astrologers claim. The gravitational influence of distant planets on a human body at birth is orders of magnitude smaller than that of nearby objects - including the delivering physician - and electromagnetic influences from those planets are negligible by comparison with terrestrial sources.1) This is not a gap-of-ignorance argument; astronomers regard the proposed mechanism as not merely undetected but physically implausible given well-characterized force laws.
Controlled studies have consistently failed to find predictive validity for astrological claims about personality traits, relationship compatibility, or life outcomes at rates exceeding chance. The most methodologically rigorous tests include:
Psychologists note that astrological belief is well-explained without invoking validity: the Barnum/Forer effect accounts for individuals finding generic personality descriptions personally accurate, and confirmation bias sustains belief against disconfirming evidence.5)
Philosophers of science do not uniformly treat astrology as a simple case of pseudoscience, though many do. Karl Popper cited astrology as a paradigm example of an unfalsifiable system.6) However, subsequent philosophers of science, including Paul Thagard, have argued that astrology fails demarcation criteria not primarily due to unfalsifiability but because its community of practitioners does not update beliefs in response to disconfirming evidence and does not seek genuine contact with other relevant disciplines.7)
This is a question internal to philosophy of science on which there is active discussion; there is no single philosophical consensus on the correct demarcation criterion, only broad agreement among philosophers of science that astrology does not meet the standards of empirical science.
Historians of science do not evaluate astrological validity and do not claim consensus on that question. Their consensus concerns descriptive and explanatory claims: that astrology was the dominant framework for celestial interpretation across the ancient Mediterranean, Islamic, South Asian, and European traditions for over two millennia; that figures now regarded as foundational astronomers (Ptolemy, Kepler, Brahe) practiced judicial astrology as a live inquiry rather than mere commerce; and that the separation of astronomy from astrology as distinct disciplines is a product of the Scientific Revolution rather than a timeless categorical distinction.8) See Astrology - History and Claudius Ptolemy - Astrology Viewpoint.
The scientific consensus addresses predictive and causal validity. It does not settle, and researchers within relevant fields have not reached consensus on, the following:
Viewpoint pages challenging or qualifying the scientific consensus: