We were talking about Astrology in Islam and how it is haraam, and a sister brought up the question that can we group people according to the time frame they were born in and say that these people have these certain qualities.These time frames don't have to match with western zodiac signs. Like saying that people born in period of March 3rd to April 27th will be passionate and those born in August 24th to Sept 27th will be risk takers and so on. Her argument is that while doing so we are not predicting someone's future, we are only talking about what kind of personality they have or might develop. I don't believe in that but I don't know how to explain it to her, why it will not be allowed. Or is it okay to do so? I would appreciate any response I can get.

Br. Ismail Kamdar answered this question beautifully. He said if there is scientific reason and proof for the material to have effect on the body, then it can be worn - like if there is observable proof of magnetic waves acting on the body, etc. But just wearing a "birth-stone", etc., does not have any scientific backing. A believer in these things will only say - but, statistics prove this and statistics prove that. This is a bit absurd. How many people from which countries participated in these tests? Have you ever been approached to participate in a test to wear a diamond and observe the effects on your body and personality? If so, I would like to know which company is doing this.., since my wife likes diamonds.

So, it appears that one must question the questioner - "On what basis are you grouping the children?" For example, if someone says that summer babies have these habits. Then I can believe that the season affects mood and personality, because it is a thing that can be studied. But even seasons cannot be generalized to the whole world. Maybe it's temperature, rain, hygiene, etc., a whole lot of individual factors.

In Mathematics, when there are too many factors causing a certain effect, and the factors cannot be numbered and measured, then it is called "Chaos Theory". For example, Google the term "Butterfly Effect" and read about it Insha' Allah.  When and where it will rain has so many causative factors, that Science can only "PREDICT" and cannot be accurate. Similarly with Child birth. And we know that Allah mentions these two specifically in the Qur'an - that He has the exclusive knowledge about these two, and these are knowledge of the unseen.

I think that "Personality" too comes under the chaos theory. Too many innumerable and non measurable factors come together to determine personality: For example:-

1. Upbringing
2. Parents
3. Islamic Knowledge
4. Education
5. Relatives
6. School, College
7. Friends-circle

and on and on and on... we can write hundreds if we had time

"Her argument is that while doing so we are not predicting someone's future, we are only talking about what kind of personality they have or might develop."  She says she is trying to judge their present and future personality based on their birth-date? If this was done in my office when recruiting someone, I think we could safely sue the person doing it, as a case of discrimination.

It is based on some data with NO backing studies/proofs.  It could be based on Hindu/Pagan scriptures. Thus, it is based on falsehood.  And, is there any proof from the Sunnah?  Did Rasool (ﷺ) ask anyone for their date of birth before he decided their roles, or was it a criteria for marriage matches? I have not heard of anything like this. Thus, we can safely say, as far as we know, it is not from Sunnah either.

Logically, this altered Zodiac system is as dumb as observing birds to see good or bad omen, or like reading hand-prints. We have other valid criteria and ways to judge the personality of people then why use this? Is it for amusement? Imagine if someone uses my birth date to tell someone else that I am a foolish person. If that is not true about me, doesn't that come under "Slander"?

I'd just like to add, that there is nothing in the deen of Islam that has been left out. Allah has mentioned everything to us in the Qur'an, and His Messenger (ﷺ) has left us upon clear guidance, as he said: "I have left you upon clear proof, its night is like its day, no one deviates from it except one who is destroyed."[1]

There is nothing from our Dunya, related matters, nor our Deen-related matters that haven't already been mentioned to us by Allah or His Messenger (ﷺ).  And so there's no need for us to turn to other nations and civilizations in matters related to hypothetical issues that have no solid proof, either from the Qur'an/Sunnah or from science.

And Allah knows best.

Reference:

[1] Ahmad (4/126), Ibn Maajah (no. 43), al-Haakim (1/96) and others - Hasan