You can learn a huge amount from ad hoc observational models of behaviour that aren't based on equations or statistics. You can even use them to make accurate predictions.

I used to know a manager who had an outstanding intuitive understanding of organisational and personal psychology. He probably couldn't have formalised his knowledge, but he had a real talent for getting shit done with individuals and groups, and for knowing exactly the right moment to apply leverage in a negotiation - all without bullying, shouting, or underhanded manipulation.

He simply knew exactly what people would do in one set of circumstances, and how to change their preferences by presenting them with alternative circumstances.

This isn't "science" in a formal sense, but it's certainly a very real form of knowledge. It seems to me STEM types tend not to understand how valuable and effective it can be, and how important it is to have some of this skill if you want to change what people do.