A lot of hate for this on HN. My challenge to the community, assume this was a good faith argument, how would you convince someone to structure a test so they were convinced astrology wasn't real? If you can't structure at least a rough outline of experiments then you don't really understand why astrology can't be real. If you defer to experts without understanding why they hold this belief then you're ceding critical thinking to someone else. If presented with evidence that astrology was real based on verifiable, repeatable experiments, then you can't claim to be logical.

Now, assuming this was a good faith question, the answer is that you need to provide a series of repeatable and testable experiments that can be independently verified by others using the same protocol [0].

There are many confounding factors that will skew results and is one of the reasons why "blinding" experiments were invented, because experimenters that had an expectation of an outcome from an experiment could pollute results from interacting with subjects [1]. As another commenter mentioned, these confounding factors can be extremely subtle [2] so extreme care has to be taken when doing these experiments. The subtlety can even extend to just repeating the experiment over a lifetime until you get a "significant" result that can be published [3].

If you were to do this in earnest, I would suggest starting with a deep literature review. There are many people doing research into ESP and other supernatural beliefs. They all haven't come up with anything accepted by the scientific community at large. It's good to understand what kind of experiments they set up so that you can see what you might be able to do and how you could replicate or extend those studies. My apologies, I don't have anything focusing on astrology specifically but a good starting point is James Randi [4] [5], the Committee for Skeptical Inquiry and the Skeptical Inquirer [6] [7].

Once you're in a position to actually conduct an experiment, my suggestion would be to start with something that is as simple as possible, with an aim to reduce any confounding factors and be independently repeatable and verifiable by others. There is a long history of experimentation in this area that has provided no evidence for supernatural effects, so a claim of supernatural effect is considered extraordinary and will need extraordinary evidence to be accepted by the community at large.

You also have to make sure to guard against people intentionally trying to sabotage your experiment as this area is full of people who are adept at lying convincingly.

There will always be people who hold irrational belief but if you provide a real experiment that is repeatable and testable independently that can show the effect you believe is real, this will convince people of rational minds that it's real.

I would also urge you to adopt a scientific mindset in that if you find no evidence supporting your hypothesis or with evidence that explains why you believed your hypothesis to be true without the need for supernatural effect, then you should abandon your hypothesis. Put another way, if you're asking an audience to believe you if you have evidence, then it's hypocritical to not change your views based on evidence as well.

[0] https://en.wikipedia.org/wiki/Scientific_method

[1] https://en.wikipedia.org/wiki/Blinded_experiment

[2] https://news.ycombinator.com/item?id=30704665

[3] https://slate.com/health-and-science/2017/06/daryl-bem-prove...

[4] https://en.wikipedia.org/wiki/James_Randi

[5] https://web.randi.org/

[6] https://en.wikipedia.org/wiki/Committee_for_Skeptical_Inquir...

[7] https://skepticalinquirer.org/