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Views of modern philosophers
Mostly bad news for astrology

An expanded version of a summary from Correlation 1995, 14(2), 33-34.

Abstract -- In ancient times the Principle of Correspondences (inference by analogy and similarity) was an accepted way of knowing. Philosophy and astrology were automatically compatible. But not any more. In the 17th century the Principle of Correspondences was seen as untenable, and in philosophy today it is deader than dead. Modern philosophy books generally ignore astrology or dismiss it as pseudo-philosophy, invalid and unjustified. A survey of 17 modern philosophers shows they can disagree on the issues that make astrology irrational. But they all agree that astrology is not a source of reliable knowledge although it can be a source of sympathy and support. Includes hints on deciding what to believe. 28 references.

Here the word philosophy (from the Greek "love of wisdom") refers to what is carried out in university departments of philosophy. It is essentially argument about wisdom, knowledge, and making rational choices. Not the same as science (investigating how the world works).

Views of ancient philosophers
In the past, in ancient Greece and during the Middle Ages, it was acceptable to draw conclusions from insight and metaphysical logic alone. There was wide acceptance of the Principle of Correspondences, or knowing by analogy, where things similar in some respects are automatically similar in other respects. If the number three has metaphysical qualities, then the third planet had the same qualities. If a planet was named after a god, then it had the same qualities. To know numbers and gods was to know planets. Nothing more was required. Thus the allocation of Aries=head through Pisces=feet was deemed so perfect that no empirical tests were needed. Analogies were infallible.

On such foundations was astrology built. Philosophy and astrology were automatically compatible. Hence the historical importance of astrology.

Not any more. In the 17th century the Principle of Correspondences became untenable. The height of John Smith tells us nothing about the height of John Brown. No longer do we believe with Aristotle that death can occur only at low tide. No longer do midwives open the door to ease a painful labour. We still use analogy as a way of description, as in people running out of steam, and as a guide to investigation, as in sound behaving like waves. But in philosophy the Principle of Correspondences as an infallible way of knowing is deader than dead. So how does modern philosophy view astrology?

Views of modern philosophy books
Modern philosophy books generally ignore astrology or dismiss it. For example The Oxford Dictionary of Philosophy (1994), and The Blackwell Companion to Philosophy (1996, 2003) ignore it, while The Oxford Companion to Philosophy (1995) dismisses it as pseudo-philosophy, defined as "deliberations that masquerade as philosophical but are inept, incompetent, deficient in intellectual seriousness, and reflective of an insufficient commitment to the pursuit of truth" (p.725). Micro-macrocosm correspondences (as in the Principle of Correspondences) are "not justified by argument, but they may have heuristic value as facilitating exploration of what would otherwise be hard to access for investigation" (p.517).

Much the same applies to modern histories of philosophy. For example The Columbia History of Western Philosophy (1999) ignores it, while in his History of Western Philosophy (1961), Bertrand Russell tends to dismiss it. He notes how in the Hellenistic world "the best philosophers fell in with the belief in astrology" (p.237), how astrology was rejected by Saint Augustine (p.355) and Aquinas (p.450), and how in the Renaissance "the first effect of emancipation from the Church was not to make men think rationally, but to open their minds to every sort of antique nonsense [notably astrology]" (p.489).

Views of modern philosophers
But why do modern philosophers ignore astrology or dismiss it? The answer is simple -- to them astrology is problematic, and not just because it is based on discredited correspondences as discussed above. What follows is a concise summary of (often lengthy) published views:

John Wilson (1963) asks is astrology a science? He argues that a science makes predictions based on an organised body of verified theories and knows why its predictions work, which in total do not apply to astrology. So the answer is no.

Diesing (1971) agrees. If astrologers were scientific there would be active collaboration with other scientists, in the same way that social and natural scientists collaborate in areas like epidemiology and urban geography. But he sees no general evidence of such collaboration.

Feyerabend (1978) compares modern astrology to medieval astronomy. It inherited interesting ideas but makes no attempt to develop them by proper research aimed at improving knowledge of extraterrestrial influences. Instead "they simply serve as a reservoir of naive rules and phrases suited to impress the ignorant." When astrologers are compared with the dogmatic anti-astrology Statement of 186 Leading Scientists, "it is interesting to see how closely both parties approach each other in ignorance, conceit and the wish for easy power over minds."

Leahey and Leahey (1988), historians and philosophers of psychology, note that astrology is largely unchanged since Ptolemy. It solves no new problems and has fossilised. Its appeal is not to astronomers, as in Babylon, or to religion, as in the Renaissance, but to pop psychology, or how to de-alienate yourself. It is less a pursuit of truth than a pursuit of happiness. It might look like a science but has none of the threat -- discover yourself (stars take the blame) and be comforted (no vengeful God). No wonder that many people prefer astrology.

Popper (1969) considers astrology to be irrational because astrologers ignore or explain away negative evidence, consider at best only peripheral claims, and make predictions too vague to be refuted.

Kuhn (1970) disagrees with the last because astrologers do not deny that many predictions fail. Instead astrology is irrational because failures are too easily explained away and therefore do not lead to the sort of research necessary for progress.

Thagard (1978) sees this as part of a broader problem, namely astrology is unprogressive and uncritical. Its theories are not progressively improved to rectify unsolved problems, as in mass disasters where people with very different charts come to the same end. Nor are they evaluated against competing theories, as in psychology or biology, that now cover the same ground. Disconfirmations are simply ignored, as in Gauquelin's work on signs.

Curry (1981) suggests a way of accommodating both Popper and Kuhn. Astrology can be seen as a Lakatosian "research programme" consisting of the fundamental but untestable hypothesis (AASB), auxiliary but testable hypotheses (eg Leos are generous), and a positive heuristic, meaning suggestions about how to proceed (eg avoid isolated factors). He notes that there are two groups of people who find astrological research intolerable, one because because astrology is obviously false and the other because astrology is obviously true. As Bertrand Russell remarked, assuming your case "has many advantages. They are the advantages of theft over honest toil."

James (1990) also disagrees with Kuhn. Astrologers do indulge in some research even though it goes nowhere. Instead astrology is irrational because of its fallacious reasoning, insensitivity to evidence, and general lack of scholarship. Even when astrologers rise up "claiming to have swept out their houses ... a cursory look ... reveals the same dreary deal."

Goldberg (1991), a sociologist, disagrees because irrationality is no reason to dismiss astrology. The real issue is "whether it is capable of making predictions that are not predicted by the more mature sciences." The matter can be decided by empirical tests.

Kanitscheider (1991) disagrees because empirical results can mislead due to errors. We should give more weight to theory. But there is no rational theory of astrology. Thus magical correspondences are not known to exist, nor are suitable physical forces -- indeed, as in the astrology of companies, there is no physical entity to act on. However this is irrelevant if people turn to astrology seeking not knowledge but sympathy and support. In other words rational refutation is pointless because "astrology fills an emotional human need ... the motivating force behind astrology has always been a person's need to deal with life." Appendix 1 gives a more detailed summary of Kanitscheider (1991).

Kurtz (1986) notes that paranormal and religious beliefs including astrology involve ignorance of the real causes, and faith in unknown or mysterious causes. "Whether astrology is empirically true or false is not the issue. Whether it works -- or is made to work -- by fulfilling a hunger for meaning is of vital significance. ... It reinforces the longing for each person to be, in some mysterious way, related to the cosmic scene over and beyond his comprehension, so that every person's life has some ultimate significance. Herein, I submit, lies the key to the persistence and success of astrology, in spite of negative evidence to the contrary about its truth".

Good (1994), an anthropologist, agrees. For critics the concern is how people can believe in astrology in today's world. But for clients the concern is simply how to gain health, wealth and happiness.

Curnow (2003) notes that such client concerns were as true of the oracles of antiquity as they are of today's sun sign columns. "There is a clear continuity in human concerns over the centuries."

Abel (1976) puts it another way. "I cannot persuade the astrologer that his theory is nonsense (I have tried!); nor can he persuade me that it is scientific; but does this stand-off imply that his predictions are exempt from scrutiny or cannot be appraised on their merits? The Jehovah's Witness and I do not appreciate each other's strong opinion about blood transfusions; but is there then no objective science of medicine?"

Grey (1999) agrees. A pseudoscience like astrology has typically one or more of three failings that distinguish it from a science, namely lack of rigour such as lack of controls, ill-defined concepts that are difficult to test or refine, and appeals to authority rather than to observation. Whereas science depends on challenges and thus advances, pseudoscience rejects them and thus stagnates. Appendix 2 gives a more detailed summary of Grey (1999, 1998).

Grey (2000) extends this to sun sign astrology: "Astrologers have had plenty of opportunity to establish the validity of sun sign astrology via double-blind tests. That they have not done so is most easily explained by the hypothesis that they cannot do so. Sun sign astrology is not knowledge but epistemological hallucination."

Kelly (2000) puts it succinctly: "No astrological body could embrace science and stay in business."

Although the above authors can disagree on which issues make astrology irrational, they all agree that astrology is not a source of reliable knowledge although it can be a source of sympathy and support. The sympathy and support provided by astrology can range from the most trivial pleasure of a sun sign column to the fulfilment of the deepest spiritual longing. As pointed out by Peter Williams (1980), a historian of American religion, "What most people cannot tolerate for extended periods is the lack ... of a larger whole in which all is fundamentally well despite occasional or even frequent breaches of order and justice." A larger whole is what astrology can provide, but not reliable knowledge. So philosophers see it as a hallucination.

Appendix 1. Summary of Kanitscheider (1991)

Bernulf Kanitscheider is professor of the philosophy of science at Justus Liebig University in Germany. Although scholars from other disciplines have discussed the status of astrology, eg the religious scholar Dr Gustav-Adolf Schoener has looked at Astrology between religion and science (see this website under Philosophy), Kanitscheider is perhaps the only modern philosopher (as opposed to say modern scholars of religion) to have devoted an entire paper (9 pages) to astrology. It typifies the modern philosophical analysis of astrology.

Rational refutation has not succeeded because "astrology fills and emotional human need. Sceptical arguments impress only a few intellectuals, whereas the motivating force behind astrology has always been a person's need to deal with life."

Analysis usually involves (1) empirical results, and (2) underlying theoretical structure. Empirical results may mislead due to errors, so we are better guided by theory. For example we do not study whether house numbers describe the occupant because numbers and occupants belong to different categories and cannot logically be related. The same applies to astrology. Just as there is no reason to suspect that butcher shops have identical numbers, so there is no reason to suspect that butchers have identical sun signs. To link categories that cannot logically be related involves severe difficulties.

To start with, known celestial forces can only influence biology. They cannot directly influence traits such as courage and love of adventure.

Suitable physical forces are not known to exist. Since the chart relates to observed positions, not actual positions, the forces travel at light speed just like radiation. But unlike radiation they are unabsorbed by the earth yet absorbed by the fetus, they exist only at birth, they do not diminish with distance, they vary qualitatively according to planet, and they are not swamped by the corresponding emanations from the earth. Furthermore, in the case of companies and ships, there is no physical entity for them to act on.

The quality depends not on the physical character of the planets but on magical correspondences involving their names or essences. Thus "the gigantic mass, or the atmosphere of cold gases, or the density of Saturn" is of no consequence. Instead "it is the god's dark and hoary looks that are responsible for generating stern and cunning men". This might be explained if the names given to planets reflected an essence perceived via the ancients' superior insight into nature, except there is no trace of such superior sources of knowledge. The basic problem is that there is no need for magical correspondences in modern thought because as yet we have observed no phenomena that require it.

Kanitscheider points out that none of the above points are relevant if people turn to astrology seeking not knowledge but sympathy and support. He concludes "It is perhaps easier to swallow the advice of a neighbour when it is disguised as an ancient star belief. If astrology became a life supporting activity, dispensing reasonable advice on conduct, and if it recognised itself as a kind of practical wisdom only in name and through history from stars and planets, then the way would be open for peaceful coexistence between astrology and astronomy."

Appendix 2. Summary of Grey (1999, 1998)

William Grey is senior lecturer in philosophy at the University of Queensland. He is one of the few modern philosophers to have interacted with astrologers (Grey 1994) and to have initiated a national survey of belief in astrology (Grey 1992). In Grey (1999) he compares science with pathological beliefs such as astrology. In Grey (1998) he gives guidance on how to decide what to believe.

Grey (1999) points out that a comparison between science and astrology tells us much about the quest for truth. First, science changes and corrects itself in response to challenges, which is one of its major strengths. In contrast, a pathological belief such ax astrology rejects challenges and thus stagnates, which stagnation is then seen as showing that astrology is true.

Second, science has progressively enriched our understanding of the world. Thus we now explain combustion without phlogiston, planetary motion without epicycles, thermal conductivity without caloric fluid, and electromagnetic radiation without a luminiferous ether. In contrast, astrology has not enriched our present understanding of the world. It is a pathological belief system that has outlasted its usefulness.

There is no clear boundary between healthy and pathological beliefs, which can make it difficult to tell one from the other. Approaches such as inductivism, verificationism and falsificationism, have proved notoriously problematic. It is easier to specify the defects of bad science than the hallmarks of good science.

Nevertheless a pseudoiscience (and also poor science) is typically marked by one or more of three distinctive failings -- lack of rigour (eg lack of controls, describing rather than measuring), ill-defined concepts that are difficult to test or refine, and appeals to authority (usually infallible) rather than observation. Whereas science depends on challenges, pseudoscience rejects them, seeing them as atfacks to be defended at all costs..

Scientific theories are abandoned when there is a better alternative, but the alternative may be slow in coming. Thus phrenology persisted for a century, the idea that bad blood causes disease (hence bloodletting) persisted for many centuries, while the four humours persisted for nearly two millennia. Longevity is no guide to truthfulness.

Trying to tell the future has always been a popular obsession. Invariably it involves the interpretation of a particular pattern (of cards, of stars, of tea leaves, etc) said to encode the future. It presupposes a determinate future, which is an idea open to dispute, and that this future can be known, which is not plausible because it would require backwards causation.

Like aeromancy, belomancy, capnomancy, dactyliomancy, halomancy, ichthyomancy, lithomancy, myomancy, ophiomancy, pegomancy, rhabdomancy, scapulomancy, and tephromancy, most of the future-telling techniques of the past are now unfamiliar, no doubt because they do not work. After all, if the ability to forsee the future existed, it would be such an evolutionary asset that it would necessarily be dominant today. But no such dominance is apparent.

So any belief system that purports to tell the future is most likely pathological. Of course well-behaved deterministic prediction systens (as in celestial mechanics) do exist, but they are special cases, and it is not hard to explain why.

Deciding what to believe?
Grey (2003) explains that deciding what to believe is the subject matter of epistemology, the seeking of rational principles for matching beliefs to evidence. If astrologers say that astrology proves that science is wrong, and scientists say the opposite, what can be done?

First, be skeptical and withhold judgement until the evidence is in. Of course it depends on the belief. We do not doubt the existence of tables and chairs, whereas we doubt the existence of Santa Claus and the tooth fairy. Between these extremes are the disputed cases such as astrology, which is where being skeptical is appropriate.

Second, prefer the ordinary to the extraordinary, and the simple to the complex. This is called Ockham's Razor. If a simple explanation such as elliptical orbits matches the observations, and so does a complicated explanation such as epicycles, the simple one is probably correct. [Similarly the experience of astrologers is equally well explained by the well-known cognitive illusions that foster false belief, and by complicated forces unknown to science, so prefer the former.]

Third, apply Hume's razor to decide whether it is rational to hold a certain belief. Ask yourself which is the more likely -- that the idea is true, or that the evidence for it is insufficient. That astrology really happens as claimed, or that its proponents are deceived by cognitive illusions, so it has a natural explanation.

Finally, be aware that our search for truth can be sabotaged by our love of wonder and by our vested interests.


Abel R (1976). Man is the Measure: A Cordial Invitation to the Central Problems of Philosophy. Macmillan, New York, page 126.

Blackburn S (1994). The Oxford Dictionary of Philosophy. Oxford University Press, Oxford.

Bunnin N and Tsui-James E (1996). The Blackwell Companion to Philosophy. Blackwell, Oxford. 2nd edition, 2003.

Curnow T (2003). Philosophy and Divination. Philosophy Now 42. A look at the relibility of oracles ancient and modern.

Curry P (1981). Astrology and philosophy of science. Correlation 1(1), 4-10

Diesing P (1971). Science, philosophy, and astrology. Chapter 25 in Patterns of Discovery in the Social Sciences, Aldine-Atherton, Chicago, pages 319-323.

Donnelly FK (1984). The perfect world of astrology. Humanist in Canada Summer 1984, 20-22.

Feyerabend P (1978). The strange case of astrology. In Science in a Free Society, NLB, London.

Good BJ (1994). Medicine, Rationality, and Experience: An Anthropological Perspective. Cambridge University Press, Cambridge UK, page 14.

Goldberg S (1991). When Wish Replaces Thought: Why so Much of What you Believe is False. Prometheus Books, Buffalo NY.

Grey W (1992). Belief in astrology: A national survey. The Skeptic [Australia] 12(1), Autumn 1992: 27-28.

Grey W (1996). Commentary on Key Topic 1 [Is the scientific approach relevant to astrology?]. Correlation 13(1): 23-24.

Grey W (1998). Ockham, Hume & Epistemic Wisdom. Philosophy Now 21, 25-28.

Grey W (1999). Pathological Belief. Cogito 13(1), 61-66

Grey W (2000). Position statement on sun sign astrology. Contributed to Dean G and Mather A, Sun Sign Columns: Response to an Invitation, Skeptical Inquirer 24(5), 36-40, September/October 2000, page 38

Honderich T (1995). The Oxford Companion to Philosophy. Oxford University Press, Oxford.

James EW (1990). On dismissing astrology and other irrationalities. In Grim P (ed), Philosophy of Science and the Occult 2nd edition. State University of New York Press, Albany NY, pages 28-36.

Kanitscheider B (1991). A philosopher looks at astrology. Interdisciplinary Science Reviews 18(3), 258-266. The original German version appeared in 1989.

Kelly IW (2000). Vested interests 1, scientific integrity 0. Skeptical Briefs 10(1), 1-2, 15.

Kuhn TS (1970). Logic of discovery or psychology of research? In Lakatos I and Musgrave A (eds), Criticism and the Growth of Knowledge. Cambridge University Press, London, pages 8-10.

Kurtz P (1986). The Transcendental Temptation: A Critique of Religion and the Paranormal. Prometheus Books, Amherst NY, pages 455 and 434-434. Astrology occupi4s pages 419-434.

Leahey TH and Leahey GE (1983). Psychology's Occult Doubles: Psychology and the Problem of Pseudoscience. Nelson-Hall, Chicago, pages 41-42.

Popkin RH ed (1999). The Columbia History of Western Philosophy. Columbia University Press, New York.

Popper KR (1969). Conjectures and Refutations: The Growth of Scientific Knowledge 3rd edition. Routledge & Kegan Paul, London, pages 37-38.

Russell B (1961). History of Western Philosophy. 2nd Edition. Allen & Unwin, London.

Thagard PR (1978). Why astrology is a pseudoscience. Proceedings of the Philosophy of Science Association, 1, 224-232. Reprinted in ED Klemke, R Hollinger & AD Kline (eds), Introductory Readings in the Philosophy of Science, Prometheus, Buffalo NY, pages 45-54.

Williams PW (1980). Popular Religion in America. Prentice-Hall, Englewood Cliffs NJ, pages 150-151.

Wilson J (1963). Thinking with Concepts. Cambridge University Press, London, pages 111-125.

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