Maimonides’ Letter On Astrology

November 22, 2017

Maimonides by Ben Shahn

Maimonides by Ben Shahn

“Truth does not become more true by virtue of the fact that
the entire world agrees with it, nor less so even
if the whole world disagrees with it.” — Maimonides


Rabbi Moses, son of Maimon, was without much argument, one of the greatest philosophers of the Middle Ages. Not only was he revered in his own time for the brilliance of his logic, he was widely read across the Arab world and in Europe through the following centuries. His ideas created an intellectual bridge between Aristotle and the so-called “Age of Reason”, between rationalism and Talmudic tradition.

At the end of the 12th century and the start of the 13th, he lived in the bustling metropolis of Fustat, then capital of Egypt, whence he had emigrated from Cordoba in southern Spain. Being both Jewish and part of the Arab world, he was able to draw on both Hebrew and Arab scholarship, as well as the classical texts of Greece and Rome.

Maimonides’ clarity of thought — and writing — is still absolutely compelling today. For example, this is the man who wrote in his Guide for The Perplexed:


“We naturally like what we have been accustomed to, and are attracted towards it. […] The same is the case with those opinions of man to which he has been accustomed from his youth; he likes them, defends them, and shuns the opposite views.”


“In the realm of Nature there is nothing purposeless, trivial, or unnecessary.”

And in his role as a doctor:

“The physician should not treat the disease, but the patient who is suffering from it.”

As a living sage, Maimonides advice was sought by other rabbis all over the Arab world and the Mediterranean, from Yemen to Montepellier. One of his responses was to an enquiry from scholars in Southern France. It’s often called The Epistle on Astrology.

You have to remember that this was written at a time when astrology was widely accepted. The French scholars were wondering whether astrologers could really predict the future accurately.

In this letter, Maimonides uses the word science to mean a system of knowledge, I suspect, since our modern definition of that word did not exactly apply. But Maimonides’ clarification of the difference between astrology and astronomy still stands today. There are many intriguing ideas in this text, aside from his thoughts on astrology. For example, he makes it clear that the world is a revolving sphere, and asks the readers to consider the question of fate, and what religion is for.

Here is what Maimonides had to say. This is from a translation from the Hebrew by the Hassidic scholar Isadore Twersky. 

27 September, 1194

“I perceive in this inquiry that although its boughs are many, they are all branches of a single tree, which is their common root: namely, all the statements of “the astrologers, the stargazers” (Is. 47:13)….

“Know, my masters, that it is not proper for a man to accept as trustworthy anything other than one of these three things. 

“The first is a thing for which there is a clear proof deriving from man’s reasoning—such as arithmetic, geometry, and astronomy. 

“The second is a thing that a man perceives through one of the five senses—such as when he knows with certainty that this is red and this is black and the like through the sight of his eye; or as when he tastes that this is bitter and this is sweet; or as when he feels that this is hot and this is cold; or as when he hears that this sound is clear and this sound is indistinct; or as when he smells that this is a pleasing smell and this is a displeasing smell and the like. 

“The third is a thing that a man receives from the prophets or from the righteous. Every reasonable man ought to distinguish in his mind and thought all the things that he accepts as trustworthy, and say: “This I accept as trustworthy because of tradition, and this because of sense-perception, and this on grounds of reason.” Anyone who accepts as trustworthy anything that is not of these three species, of him it is said: “The simpleton believes everything.” (Prov. 14:15).

“Thus you ought to know that fools have composed thousands of books of nothingness and emptiness. Any number of men, great in years but not in wisdom, wasted all their days in studying these books and imagined that these follies are science. They came to think of themselves as wise men because they knew that science. 

“The thing about which most of the world errs, or all of it—save for a few individuals, “the remnant of whom the Lord shall call” (Joel 3:5)—is that thing of which I am apprising you. The great sickness and the “grievous evil” (Eccles. 5:12, 15) consist in this: that all the things that man finds written in books, he presumes to think of as true—and all the more so if the books are old. And since many individuals have busied themselves with those books and have engaged in discussions concerning them, the rash fellow’s mind at once leaps to the conclusion that these are words of wisdom, and he says to himself: “Has the pen of the scribes written in vain” (Jer. 8:8), and have they vainly engaged in these things?

This is why our kingdom was lost and our Temple was destroyed and why we were brought to this; for our fathers sinned and are no more because they found many books dealing with these themes of the star gazers, these things being the root of idolatry, as we have made clear in Laws Concerning Idolatry. They erred and were drawn after them, imagining them to be glorious science and to be of great utility. They did not busy themselves with the art of war or with the conquest of lands, but imagined that those studies would help them. Therefore the prophets called them “fools and dolts” (Jer. 4:22). And truly fools they were, “for they walked after confused things that do not profit” (I Sam. 12:21 and Jer. 2:8).

“Know, my masters, that I myself have investigated much into these matters. The first thing I studied is that science which is called judicial astrology—that is, (the science) by which man may know what will come to pass in the world or in this or that city or kingdom and what will happen to a particular individual all the days of his life….

“…Know, my masters, that every one of those things concerning judicial astrology that (its adherents) maintain—namely, that something will happen one way and not another, and that the constellation under which one is born will draw him on so that he will be of such and such a kind and so that something will happen to him one way and not another—all those assertions are far from being scientific; they are stupidity. There are lucid, faultless proofs refuting all the roots of those assertions.

“Never did one of those genuinely wise men of the nations busy himself with this matter or write on it, no (nation) wrote such compositions or committed the error of calling it a science, other than the Chasdeans, Chaldeans, Canaanites, and Egyptians, for that was their religion in those days. But the wise men of Greece—and they are the philosophers who wrote on science and busied themselves with all the species of science—mock and scorn and ridicule these four nations that I have mentioned to you, and they rally proofs to refute their entire position “root and branch” (Mal. 3:19). The wise men of Persia also recognized and understood that all that science which the Chasdeans, Chaldeans, Egyptians, and Canaanites produced is a falsehood and a lie. Do not imagine that those refutations are mere assertions and that we therefore should not put our trust in them; rather there are lucid and correct, faultless proofs to refute that entire position, and the only one who would cling to it would be “a simple one who believes everything”(Prov. 14:15), or one who wishes to deceive others.

“And know, my masters, that the science of the stars that is genuine science is knowledge of the form of the spheres, their number, their measure, the course they follow, each one’s period of revolution, their declination to the north or to the south, their revolving to the east or to the west, and the orbit of every star and what its course is. On all this and the like, the wise men of Greece, Persia, and India wrote compositions. This is an exceedingly glorious science. By means of it, the onset of the eclipses of luminaries may be known and when they will be eclipsed at any given place; by means of it there may be known the cause for the moon’s (yareah) appearing just like a bow, then waxing great until it is full, and then gradually waning; by means of it there may be known when the moon (levanah) will or will not be seen; and the reason why one day will be long and another day short; and the reason why two stars will rise as one, but not set together; and the reason why a given day at a given place is thirteen hours long and in another place fifteen or sixteen or twenty hours long, yet being a single day. (In one place the day and the night will be of equal duration; in another place the day will be like a month or two months or three—so that a place may be found where the entire year is a single day, six months daytime and six months nighttime.) How many amazing conditions are made intelligible by this science, all of which is undoubtedly true. It is this calculation of astronomical cycles of which the (Talmudic) sages said that it is wisdom and understanding in the sight of the (Gentile) peoples. But as for these assertions of the stupid astrologers, they are nothing. I am now making clear to you the main points of those matters that are the mystery of the world.

“Know, that all the wise men of the Gentile nations—and they are the great philosophers, men of intellect and science—were all in accord that the world has a Governor; He makes a sphere revolve, the sphere not revolving of itself. They have many books advancing a lucid proof for this; on this point there is no controversy among men of science. There is, however, a great controversy among them regarding this entire world, namely, the sphere and what is beneath it

“… All these, then, are the three sects into which the wise men of the world fall, from the earliest antiquity down to now.

“(1) Those who maintain that the sphere is not a created thing, but that it eternally has been and will be just as it is.

“(2) Those who maintain that the Deity has created it out of that matter which always exists by Him.

“(3) Those who maintain—just as all the prophets did—that there is no other thing that is with the Deity, just He Himself, and that when He wished, He brought forth this world out of nothing, in conformity with His will.

“All of these three sects are in accord on the following point. Everything that comes into being in this lower world—namely, every “living soul” (Gen. 1:30) and every tree and every species of grass and every one of the species of minerals—the whole has the Deity as its maker, through a power coming from the spheres and the stars. And they are in accord that the power of the Creator flows first upon the spheres and the stars; from the spheres and the stars it flows and spreads through this (lower) world—everything that is, thereby coming into being.

“Just as we maintain that the Holy One, blessed be He, performs signs and wonders through the angels, so do these philosophers maintain that all these occurrences in the nature of the world come through the spheres and the stars. They maintain that the spheres and the stars possess souls and knowledge. All these things are true. I myself have already made it clear, with proofs, that all these things involve no damage to religion. And not only this, but what is more I have understood from the sayings of the sages in all of the Midrashim that they maintain as the philosophers maintained. There is no controversy whatever between the sages of Israel and the philosophers on these matters, as I have made clear in those chapters [in the Guide of the Perplexed, a philosophical treatise].

“All three of these sects of the philosophers, which maintain that everything is made by means of the spheres and the stars, also maintain that whatever happens to each and every human being is due to chance; it is not due to any cause coming from above, and neither the constellation under which one is born nor nature will avail against it. There is no difference for them between this individual who was torn to pieces by a lion that happened upon him, or this mouse that was torn to pieces by a cat, or this fly that was torn to pieces by a spider. Neither is there a difference between a roof’s falling upon and killing someone, or a rock’s breaking loose from a mountain and falling upon a tree or upon another rock and breaking it. All this, they maintain, is simply fortuitous. It is said as well of those human beings who are warring with one another over a great kingdom, that they are like a pack of dogs warring over a carcass. This is not due to any cause coming from the stars. Furthermore, this one being poor and that one rich, this one having children and that one being childless—all the philosophers maintain that this is due to chance. The summary of the matter is that they maintain that what happens to each and every thing—be it man or beast or trees and minerals—is all due to chance. But the being of all the species and the things comprehended in the entire world—in which there is not the activity of a living soul—all of this stems from the power of the spheres whose root, in turn, comes from the Holy One, blessed be He.

The controversy lies in this, that the true religionists, and that is the religion of Moses our Teacher, maintain that what happens to individuals is not due to chance, but rather to judgment….This is a root of the religion of Moses our Teacher, that everything happening to human beings is a (just) decree and judgment. Hence, the sages maintained: “There is no death without sin and no affliction without transgression” (Shabbat 55a).

And know, my masters, that it is one of the roots of the religion of Moses our Teacher—and one that all the philosophers also acknowledge—that every action of human beings is left to them and that there is nothing to constrain or draw them. Rather, if he so pleases, a man will worship God and become wise and sit in the house of study. And if he so pleases, he will follow the counsel of the wicked and run with thieves and hide with adulterers. There is no influence or constellation under which one is born that will draw him in any manner toward any one of these ways. Hence it was commanded and told to him: “Do this and do not do that.” …Thus we ought to know that what happens to human beings is not—as the philosophers maintain—like what happens to the beast.

“Three disagreements are to be found in these matters. Imagine this situation. Here is Reuben, a tanner, poor, and his children have died in his own lifetime. And here is Simon, a perfumer, rich, and his children stand before him.

“(1) The philosopher will maintain that this is due to chance. It is possible that Reuben could become a perfumer, grow rich, and have children; and it is possible that Simon could become impoverished, turn into a tanner, and witness his children’s death. All this is simply fortuitous. There is no nature in the world and no power emanating from a star that caused this individual to be or not to be thus. This is the position of the philosophers.

(2) The second position is that of those who believe in judicial astrology and whose sayings you have heard and whose follies are widespread among you. They maintain that it is impossible that a given thing should ever change. Never will Reuben be anything other than a tanner and poor and childless, for it was thus fixed by the power of the sphere at the time of his birth. Similarly, it is impossible for Simon to be anything other than a perfumer and rich and with surviving children, just as it was fixed by the power of the sphere at the time of his birth.

These two ways, or these two positions, are regarded as falsehoods by us. The position of the astrologers is given the lie by reason, for correct reasoning has already refuted, by means of lucid proofs, all those follies that they have maintained. It also is regarded as a falsehood by us because of the religious tradition, for if the matter stood thus, of what utility would the Torah and the commandment and the Talmud be to a particular individual? For in that event, every single individual would lack the power to do anything he set his mind to, since something else draws him on—against his will—to be this and not to be that; of what use then is the command or the Talmud? The roots of the religion of Moses our Teacher, we find, refute the position of these stupid ones—in addition to reason’s doing so with all those proofs that the philosophers maintain to refute the position of the Chasdeans and the Chaldeans and their associates. The position of the philosophers who maintain that these things are due to chance is also regarded as a falsehood by us because of the religious tradition.

(3) The true way upon which we rely and in which we walk is this: We say regarding this Reuben and Simon, that there is nothing that draws on the one to become a perfumer and rich, and the other to become a tanner and poor. It is possible that the situation will change and be reversed, as the philosopher maintains. But the philosopher maintains that this is due to chance. We maintain that it is not due to chance, but rather that this situation depends on the will of “Him who spoke, and (the world) came into being” (Ps. 33:9); all of this is a (just) decree and judgment. We do not know the end of the Holy One’s wisdom so as to know by what decree and judgment He required that this should be this way and that that should be the other way; “for His ways are not like our ways, neither are His thoughts like our thoughts” (Is. 55:8). We rather are obliged to fix in our minds that if Simon sins, he will be punished with stripes and impoverished and his children will die and the like. And if Reuben repents and mends his ways and searches his deeds and walks in a straight path, he will grow rich and will succeed in all his undertakings and “see (his) seed and prolong (his) days” (ibid. 55:10).

This is a root of the religion. If a man says, “But look, many have acted in this way and yet have not succeeded,” why, this is no proof. [For] either some iniquity of theirs caused this, or they are now afflicted in order to inherit something even better than this.

The summary of the matter is that our mind cannot grasp how the decrees of the Holy One, blessed be He, work upon human beings in this world and in the world to come. What we have said about this from the beginning is that the entire position of the stargazers is regarded as a falsehood by all men of science.

I know that you may search and find sayings of some individual sages in the Talmud and Midrashim whose words appear to maintain that at the moment of a man’s birth, the stars will cause such and such to happen to him. Do not regard this as a difficulty, for it is not fitting for a man to abandon the prevailing law and raise once again the counterarguments and replies (that preceded its enactment). Similarly it is not proper to abandon matters of reason that have already been verified by proofs, shake loose of them, and depend on the words of a single one of the sages from whom possibly the matter was hidden. Or there may be an allusion in those words; or they may have been said with a view to the times and the business before him. (You surely know how many of the verses of the holy Law are not to be taken literally. Since it is known through proofs of reason that it is impossible for the thing to be literally so, the translator [of the Aramaic Targum] rendered it in a form that reason will abide.) A man should never cast his reason behind him, for the eyes are set in front, not in back.

“Do not censure me, my masters, for the brevity of these remarks… Farewell, my brothers, friends, and masters; may you increase and be exalted forever. Amen.


So he was not a fan of astrology, especially of astrologers who think they know everything because they’ve read a load of books. Perhaps it shows the kind of astrologers he encountered. Maimonides was a well-travelled man with wide acquaintance, so it’s likely that he might have been referring to people he knew. Some of us may even have met astrologers like this today!

Maimonides’ clear reasoning must be one of the most coherent arguments against astrology and probably had a detrimental effect on its status over the following centuries.

Here’s something else he said.

“I will destroy my enemies by converting them into friends.”

Hmm — typical Aries with Libra Moon…


history, philosophy & ethics


Christina said:

For more on the word “science” — which is an important concept in the debate on astrology, since we are often called a pseudo-science — follow this link


Mary said:

Thank you so much for this post! I haven’t read Maimonides since my university days, and as with many thinkers I first encountered in my youth, I appreciate his exquisite insight much more deeply now.


Jem said:

On a little differing note but possibly also along similar lines, I have been reading in depth the works of St Getrude the Great, a renowned medieval Benedictine mystic and Saint born in Eisleben, Thuringia, Germany. The reason I have raised this issue, is that she too lived in the 12th and 13th century like Maimonides. I was wondering could there be any astrological correlation connected to the present interest in uncovering such deep wisdom? (Neptune direct? Jupiter in Scorpio? Pluto in Capricorn – need for fruitful finds after U-Plu square?)Why is this so fascinating to us now? I know that there was a blossoming of saints during this time. I was born in December 1968 so perhaps this is merely a personal issue but the bells have indeed begun ringing.


Christina said:

Aha — well Neptune was in Pisces and Pluto and Uranus were both in Cancer. They were not conjunct yet — that would be in a few years time since Uranus had only just go there. Saturn had just gone into Capricorn — just as he will on December 20 this year. So we’ve got some resonance there I think with Cancer-Capricorn axis activated, the relationship between Uranus and Pluto and Neptune in Pisces


Mary said:

I’m a December 1968 baby too! Maybe we are looking for wise teachers as part of the Chiron return for those born at that time?


Jem said:

Thank you both Christina and Mary, what wonderful insights. That Neptune was in Pisces during that period in history is certainly interesting, as well as the fact that Saturn was in Capricorn. We are heading for a pluto saturn conjunction in Capricorn in 2020 (I think), so plenty of fuel there for wanting to probe the depths. (And Capricorn is known to have a mystical [sea-goat] side, afterall) I agree with you Mary, about the Chiron return, ours is in Pisces opposite pluto in virgo – the need for healing in deep waters is most relevant at this time.


Jem said:

Not forgetting that our Chiron return also features a natal trine to Neptune in scorpio. Prompting even more questing for deep healing.


mike said:

Well, ontologists are entitled to their opinions. Perplexing that psychology, economics, and political science don’t withstand the test of science, yet have been given the acceptability while searching for substantiating scientific evidence. Interesting that astrology is often utilized to examine and make sense of these same disciplines.


Christina said:

Have you been following the stupid debate about dowsing in the Guardian and on R4 Today show?

Some blogger has discovered “shock” that 10 out of 12 water companies here use dowsing. This has been spun as a disgraceful waste of money because it can’t possibly work, because it’s not “sciencey” enough. Cue “scientists” on the radio and in print getting all righteous about dowsing.

Of course, it could have been spun the other way. If water companies use dowsing regularly then it probably works. It’s cheap, clean and efficient. We don’t know how it works but it does.

If something as simple and easy to show as effective as dowsing gets this kind of hysterical response, what hope do we astrologers have?

On the Today show, that old dinosaur John Humphrys explained that he himself had dowsed successfully for water on his own land despite being a total sceptic. His interlocutor told him it was all in his mind!


Jane said:

I thought it was quite perfectly synchronous that this spluttering ‘debate’ about dowsing has cropped up just as Jupiter in Scorpio is approaching the trine to Neptune in Pisces! Water divining is basically very practical, not a magic trick. It works very well when you need it, but probably wobbles when tested under the boring and pointless conditions of a ‘scientific’ test. People working for the water authorities would not practice it if they didn’t think it was useful. I’ve been dowsing since I was 13, and you can actually do it without any dowsing rods. You feel the tingling in your fingers. I suspect some sort of electro-magnetic energy is involved. Since we have almost a year of Jupiter trine Neptune ahead, perhaps some new information will emerge that might invite some of the sceptics to be a little more curious about many things. After all, isn’t that the basis of scientific enquiry?


Christina said:



mimi said:

The world is divided in this era.
There are the have’s and the have not and there are also the knowing and the not-knowing or should I say the concious and the unconcious

Until humanity is willing to look at astrology for what it is we will have to bide our time and be the group within society that are simply more concious than the rest.

Astrology has to do with wisdom combined with intelligence and the hunger to wanting to know why things are the way they are, needing to explain what happens in our world.


Phillustrator said:

I was taught how to dowse as a child, growing up in darkest East Anglia. It works. I don’t get the tingling in the fingers, but what I can only describe as a kind of pulling sensation in my body. Curiously my Neptune rising, Piscean mother can do it using a pendulum and a map!


Christina said:

Mimi — I like that wisdom and intelligence — maybe Pallas and Uranus, although I think Saturn’s important too, sparked by Mercury.


Sonja Foxe said:

Has Maimonides said anything about the OT’s Daniel … who taught the Babylonian starry arts to the Persian Magi, and by dint of Cyrus’s appreciation became head Magi and created conditions for the end of the Babylonian Diaspora circa 600 bc


Christina said:

He did comment more on astrology in the Old Testament in other writings, but I am not sure about that specific example. In general, he dismissed astrology fairly roundly.


mike said:

Re dowsing = pseudoscience
The term “idiomotor effect” is used to explain the dowsers’ hand movements via their subconscious, therefore invalidating dowsing. The term derives from psychology [ ]. Psychology, itself, is a pseudoscience! Wiki’s ‘Psychology” page starts by defining psychology as a science, but further down that page is a section discrediting psychology based on lack of scientific methods [ ]. Wiki’s “Pseudoscience” page ironically has a psychology section [ ] stating:
“The psychology of pseudoscience attempts to explore and analyze pseudoscientific thinking by means of thorough clarification on making the distinction of what is considered scientific vs. pseudoscientific.”

I accept prescience or protoscience rather than pseudoscience.
From Wiki [ ]
“The term prescientific means at root ‘relating to an era before science existed’. For example, traditional medicine existed for thousands of years before medical science did, and thus many aspects of it can be described as prescientific. In a related but somewhat different sense, protoscientific topics (such as the alchemy of Newton’s day) can be called prescientific, in which case the proto- and pre- labels can function more or less synonymously (the latter focusing more sharply on the idea that nothing but science is science). Compare fringe science, which is considered highly speculative or even strongly refuted. Some protosciences go on to become an accepted part of mainstream science.”


mike said:

“Amateur explorers discover vast underground passage beneath Montreal”
“,,, In 2014, Caron – using dowsing, a technique sometimes used to locate ground water – detected an anomaly in the ground, suggesting a passage or a void could lie beyond the existing cave.”


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