By soft science we mean, science conducted on phenomena that don’t tend to come with numbers already attached. And by hard science we mean science that has been around long enough to have acquired the ability to have numbers already attached.
That is a pretty clear definition of hard and soft science. This is from INSNA’s keynote address about ten years back. One of the two speakers, Peter Killworth, just passed away which I learned from the INSNA list-serv, SOCNET.
The address looks like its worth reading. Of course one is immediately struck by the very INSNA-y approach of having a physical scientist and an anthropologist. That kind of deeply interdisciplinary work seems to be often the hallmark and honey (attractiveness) of research that attracts netheads. (Did I just coin that? An off shoot of orgheads?)
The idea of social physics has come up before. Harrison White and Duncan Watts more recently, at least in terms of their career trajectories. Also, I recall one fo those grand daddy type sof social science (Comte? Sant-Simone?) said something to that effect. Maybe I can check later…