The distinction is not between hard subjects and soft subjects (which implies a degree of difficulty) or between technical and non-technical (which implies the necessity of technique), but between non-narrative and narrative disciplines.
Non-narrative disciplines examine or manipulate the present moment and operate deterministically. Mathematics, most physics (that we are aware of), programming, surgery, carpentry, casino games, and cooking, to name a few. Interpretation is irrelevant in these disciplines: what works, works, and what doesn’t, doesn’t. Properties can be mapped empirically. In fact, that’s the only way they can be mapped.
Narrative disciplines examine or manipulate the past, the future, or imagined worlds. They do not operate deterministically, no matter how badly we’d like them to – or how emphatically “experts” insist. They are not “subject to” interpretation; they are interpretation. Artists, historians, economists, chefs, social scientists, UX designers, war fighters all share in this domain.
The danger is when non-narrative practitioners mistake their field for narrative, and vice versa.
In the former case, we narrate – tell stories about – why a given outcome has occurred. We declare we have beginners’ luck because we won the first round. We invent deities to explain the drought. Or, we dismiss evidence when we cannot easily produce an explanation: chiropractic treatment must be quackery because we don’t see a link between spinal manipulation and chronic knee pain. Besides, chiropractors don’t even have an M.D. (certification being another type of narration)!
In the latter case, we apply rules and statistics to systems that operate under randomness. We invent categories of people, predict the behavior of “rational” actors, forecast the next war based on the previous one. We are comforted when a man in dark rimmed glasses tells us we have nothing to worry about. His model has taken into account the past, and runs on very expensive computers.
In any case, we’re sure that this time we’ve finally figured it out. And then we get a rude surprise.