On the hard and soft sciences in public health

摘要

Many of my friends and colleagues who conduct public health research in a controlled environment regularly and casually invoke the moniker "hard and soft science." My reflexive query, "What does that mean exactly?" generally leads to a self-conscious reply and a fairly quick change of subject, and so I have decided to explore the question in this essay, "What does that mean exactly?" Oxford defines science as "the intellectual and practical activity encompassing the systematic study of the structure and behavior of the physical and natural world through observation and experiment." On the supposed distinction between "hard" and "soft" science, Oxford is silent. I think what my friends and colleagues sometimes have in mind by hard science is physicality, such as the hard surfaces of laboratory counters, centrifuges, and pipettes; and the physical presence of things such as skin, bones, and water samples. Perhaps "soft" here implies abstract. Sometimes I think what they have in mind has to do with reliability, i.e., that the results of "hard" science are more reproducible or consistent than are results from "soft" science (in fact, Hedges concluded from his systematic empirical comparison that "the results of physical experiments may not be strikingly more consistent than those of social or behavioral experiments"). Sometimes I think they're trying to say something about validity or epistemology, i.e., the "hard" truth vs. the "soft" or squishy truth. What is clear when they say it is that from their point of view, "hard" is highly valued, while "soft" is much less so.