Um, what? There are clear neurological and bio-chemistry based aspects of the brain that are about as scientific as it gets. Do you think psychiatric medications were just randomly made and given to people without having some sort of “science” based reason why they work?
I don’t understand your analogy about an astrologer. Yes, we can measure the brain for lots of things. Neurotransmitter levels, electrical activity, physical damage, etc. There are clear relationships to those things and behavior. How is that not science?