The hard sciences—physics, chemistry, astronomy, etc.—boasted remarkable achievements in the 20th century. The credibility and prestige of all science went up as a result. Academic disciplines outside the sciences rushed to append “science” to their names to share in the glory.
Science has an image of infallibility based on the success of the hard sciences. When someone says “You can’t argue with science,” I’d rather they said “It’s difficult to argue with hard science.”
The soft sciences get things wrong more often. Sciences such as biology and epidemiology — soft compared to physics, but hard compared to sociology — often get things wrong. In softer sciences, research results might be not even wrong.
I’m not saying that the softer sciences are not valuable; they certainly are. Nor am I saying they’re easier; in some sense they’re harder than the so-called hard sciences. The soft sciences are hard in the sense of being difficult, but not hard in the sense of studying indisputably measurable effects and making sharp quantitative predictions. I am saying that the soft sciences do not deserve the presumption of certainty they enjoy by association with the hard sciences.
There’s a similar phenomena in computing. Computing hardware has made astonishing progress. Software has not, but it enjoys some perception of progress by association. Software development has improved over the last 60 years, but has made nowhere near the progress of hardware (with a few exceptions). Software development has gotten easier more than it has gotten better. (Old tasks have gotten easier to do, but software is expected to do new things, so it’s debatable whether all told software development has gotten easier or harder.)