Well, the discussion of the differences between the hard and the soft sciences is a complicated topic.
But very crudely, the soft sciences have to deal with situations which never exactly repeat, so their theories and laws are always approximate and apply “more or less”. In particular, this makes it hard to falsify theories which leads to proliferation of just plain bullshit and idiosyncratic ideas which cannot be proven wrong and so continue their existence. Basically you cannot expect that a social science will reliably converge on truth the way a hard science will.
So if you pick, say, an undergraduate textbook in economics, what it tells you will depend on which particular textbook did you pick. Two people who read two different econ textbooks might well end up with very different ideas of how economics work and there is no guarantee that either of them will explain the real-world data well.
Well, the discussion of the differences between the hard and the soft sciences is a complicated topic.
But very crudely, the soft sciences have to deal with situations which never exactly repeat, so their theories and laws are always approximate and apply “more or less”. In particular, this makes it hard to falsify theories which leads to proliferation of just plain bullshit and idiosyncratic ideas which cannot be proven wrong and so continue their existence. Basically you cannot expect that a social science will reliably converge on truth the way a hard science will.
So if you pick, say, an undergraduate textbook in economics, what it tells you will depend on which particular textbook did you pick. Two people who read two different econ textbooks might well end up with very different ideas of how economics work and there is no guarantee that either of them will explain the real-world data well.
This is also true of evolutionary biology—I think it’s not widely recognized that evolutionary biology is like the soft sciences in this way.