As a matter of fact astrology has never been scientifically disproved, nor has any rational ground ever been advanced for treating it as a pseudo-science. It simply came to be assumed at a certain period and under certain intellectual influences that it was a childish superstition. Or if there were any grounds, then it was left aside because astrologers were charlatans, because many, perhaps most predictions went wrong, but most of all because it was thought that in the nature of things, in any rational theory of the universe the planets simply could not have any influence on our characters, lives and actions. None of these grounds are sufficient. If many astrologers are charlatans, so also have there been many quacks in the field of medicine; at one time indeed not only did they pullulate, but the system of medicine itself seemed so defective that there were plenty of clear and enlightened minds who were inclined with Molière to denounce the whole thing as a gross pseudo-science, an elaborate and solemn system of ignorance, humbug and quackery. Supposing that view had prevailed,—it could not, merely because men are too vitally interested in healing their ailments and preserving their bodies and know no other way of doing it,—that would not have done away with the truth underlying the science. That many predictions go wrong, proves nothing, essentially, against astrology any more than the constant failure of doctors to heal diseases proves anything essential against their science.
[SABCL, 17:28485]
The a priori argument from the rational theory of the universe cannot stand. There is nothing essentially irrational in the idea that in this solar system, so closely linked together, there may be mutual influences of all the planets upon each other or that the beings of a particular planet are powerfully influenced or even dominated by influences from the others. The question remains, the a priori rationality being admitted or at least not summarily dismissed, first, whether it is so in fact and, secondly, how far those influences go and of what nature they are. Astrology affirms that they not only affect our bodies, but also our psychical being. If matter and mind were entirely independent entities having no influence or determining effect upon each other, then such a result could not be; but that is not the case. According to the materialistic view of the universe which claims to be the sole rationalistic view, mind is itself an effect of matter and all its states and movements are determined by matter. There is nothing then impossible, planetary influence being once admitted, in the action of material bodies producing psychical conditions on the earth and thereby determining our psychical states and movements. In a more truly rationalistic view mind and matter are always influencing and determining each other; here too, given a universal mind and matter so acting upon individual matter and mind, the movements of the planetary system may be one or even the first nodus of their activities, and the assertions of astrology become at least primarily credible.
[SABCL, 17:28586]

Stars Only Indicate and Do Not Determine Our Destiny

Many astrological predictions come true, quite a mass of them, if one takes all together. But it does not follow that the stars rule our destiny; the stars merely record a destiny that has been already formed, they are a hieroglyph, not a Force,or if their action constitutes a force, it is a transmitting energy, not an originating Power. Someone is there who has determined or something is there which is Fate, let us say; the stars are only indicators. The astrologers themselves say that there are two forces, daiva and purusakara, fate and individual energy, and the individual energy can modify and even frustrate fate. Moreover, the stars often indicate several fate-possibilities; for example that one may die in mid-age, but that if that determination can be overcome, one can live to a predictable old age. Finally, cases are seen in which the predictions of the horoscope fulfil themselves with great accuracy up to a certain age, then apply no more. This often happens when the subject turns away from the ordinary to the spiritual life. If the turn is very radical, the cessation of predictability may be immediate; otherwise certain results may still last on for a time, but there is no longer the same inevitability. This would seem to show that there is or can be a higher power or higher plane or higher source of spiritual destiny which can, if its hour has come, override the lower power, lower plane or lower source of vital and material fate of which the stars are indicators. I say vital because character can also be indicated from the horoscope much more completely and satisfactorily than the events of the life.
[SABCL, 22:46768]

What Does Astronomy Depend On?

ASTROLOGY depends on three things, the position of the planets in the heavens and with regard to each other, the condition of the planets at the natal hour or at the moment of enquiry, and the general character or tout-ensemble of the horoscope. Any error or deficiency with regard to their mutual relations will affect the work of the astrologer and vitiate its correctness or its completeness. To cast a horoscope completely is one of the most difficult operations known to science. The astrologer is born not made. It is as impossible to manufacture a perfect astrologer by education as to manufacture a poet. Hence the disrepute into which the profession of astrology too lightly and numerously followed, has fallen in the Kaliyuga.
[SABCL, 17:255]

Do Twins Have Same Destiny Because They Are Born at the Same Time?

The character of the horoscope is determined by the number of elevated, fallen, ascending, descending or entrenched, progressive or retrograde, rapid, sluggish or moderate, well-housed or ill-housed or the rising, convergent or divergent planets; by the numbers and nature of the planetary relations, conjunctions, aspects, oppositions, by the character of the ascendant, its lord and its tenant, combinations, distributions. All these circumstances have to be considered in order to determine whether the horoscope is great, mediocre or petty, favourable or malign, strong or weak. The results have to be judged according to the character. The same details in a good horoscope will mean something very different from what they could mean in one that is petty or malign or even merely strong. Moreover, even if all the positions are the same, yet the infinitesimal shifting of a planet or a change in its character will often mean the difference between life and death, success or failure. This is the reason why twins sometimes have different destinies, one dying, another living, or pursue an identical course up to a certain point, then diverge.
[SABCL, 17:256]

Is the Character of a Person Determined by the Birth Sign Alone?

It is not always the sign of birth … that is most powerful in fixing the temperament, it is sometimes the sign in which the sun or the moon or else the lord of the horoscope is situated; and none of these signs can be neglected. If they are all taken into consideration according to their respective force in the horoscope, a correct idea of the character may be formed; but even then the position and mutual relations of their lords must be taken into the account. This is the reason why men born under the same sign vary so much in character.
I must … guard against the idea that the signs and planets determine a man’s character or fate. They do not, they only indicate it, because they are the sensational, celestial and astral influences or nervous force in Nature which become the instruments of our Karma.
 …man is mightier than his sensations or vitality or the sensational or vital forces of the universe. Our fate and our temperament have been built by our own wills and our own wills can alter them.
[SABCL, 17:258]
Even if the prediction were a correct one according to the horoscope it need not fulfil itself, because by entering the spiritual life one opens to a new force which can change one’s destiny.
[CWSA, 35:58]

Stars Have No Decisive Influence

The stars have no decisive influence. It is only if one does not believe in the Divine that one unnecessarily suffers by believing that they determine one’s life.
I have known many astrologers both in Europe and India. So far, nobody has been able to read the future correctly. There are three reasons for the failure. First, the astrologers do not know how to read the future properly. Secondly, the horoscope is always incorrectly made—unless a man is a mathematical genius. And even for such a person it is very difficult to make a correct horoscope. Thirdly, when people say that the stars in this or that house at the time of birth rule your life, they are quite wrong. The stars under which you are born are only “tape-recorders” of physical conditions. They do not rule the future of the soul. There is something beyond, which rules the stars themselves and everything else. The soul belongs to this Supreme Being. And if it is doing Yoga, then all the more it should never believe in the power of the stars or in any other power.
An astrologer who predicts a catastrophe for you is like a joker. Many jokers say things like, “Today you will break your neck!” But in spite of the joke nothing happens. Only a great Yogi can tell you your future correctly. But even then there is the Supreme Will which alone controls and decides everything.
[CWM2, 15:34]
It does not seem to me established that the stars determine the future—though that is possible, but it does look as if they indicate it—or rather, some certitudes and potentialities of the future. Even the astrologers admit that there is another element of determination in man himself which limits the field of astrological prediction and may even alter many of its ascertained results. There is a very tangled and difficult complex of forces making up any determination of things in the world and when we have disentangled one thread of the skein and follow it we may get many striking results, but we cannot rely on it as the one wholly reliable clue.
[SABCL, 22:228]

Influence of Yoga Is More Powerful Than the Stars

Horoscopes have no importance for those who take up yoga, because the influence that works through yoga is much more powerful than the influence of the stars.
[CWM2, 15:35]
An acceptance of the truth of astrology would not necessarily carry with it a complete determinism of Fate or mechanical law of Karma. In the Indian theory at least there is room for a determination by human will and endeavour, for Fate is mainly a determination by past action and a new will and action can cancel it; only a very strong Karma is imperative and irreducible. Even that may possibly be cancelled if one can enter into the freedom of the spiritual consciousness. One instance at any rate come to my knowledge in which the life had corresponded exactly with the pre-indications of the horoscope so long as the subject remained in the world but, as soon as he left it for a spiritual life, there was no longer any correspondence.
[SABCL, 17:289]
Why do you believe in what the Astrologers say? It is the belief that brings the trouble.
Sri Aurobindo says that a man becomes what he thinks he is.
[CWM2, 12:157]
…one of the greatest ecstasies possible is to feel oneself carried by the Divine, not by the stars or Karma, for the latter is a bad business, dry and uncomfortable—like being turned on a machine, yantrarudhani mayaya.
[SABCL, 22: 470]