I have an unpopular view, that physics is probably the easiest science. Chemistry is harder, biology is even harder. Heading up the chain into social sciences is just unbelievably hard to get good answers.
With physics, you can build a machine an test to your hearts content to determine what the underlying rules are. That's real tough to do when you're studying, say, an economy.
So, i don't mean this as a slight to physicists. It would never occur to me to use oil drops to measure the mass of an electron. It was a brilliant insight. But, with modern tools, I kinda think i could replicate that experiment in my apartment. Evolution? I mean, golly, that's a really subtle insight. I might be able to do something with petri dishes and poisons, but that seems like a pretty tough thing to detect. I'd like to compare Darwin to Newton, but Darwin is probably closer to Aristotle. We haven't begun to get to the really good stuff yet.
I'm skeptical of phycology, there are issues with replication all the time. But clearly they're on to something. The whole advertising industry is built on psychological insights.
I've dealt with crazy race conditions that make me want to pull my hair out. They're not consistently reproducible. Eventually i work out the logic and things fall into place. But i have access to the source :) I can't imagine how hard it is to get anything out of random interactions of black boxes. Social sciences just aren't for me.
Anyway, yeah, i believe it's possible to model human interactions. We do it all the time. As with all things, some models are just more useful than others.