I would not be so sure that the opposite or the alternative to modernity is the "post-modern" world. I would be much more careful with the term "postmodernism".

On the one hand, it was really a fashion - an important fashion, certainly, coined by some prestigious French thinkers, and later on re-taken by many American thinkers, too. However, beyond those references, the truth is no one else really works with that. Not in Germany, not in Italy, not in many other places (we all know).

I get the point of the question, though. Modernity was fundamental in many concerns. Nonetheless, it no not true that we live in the midst of relativism. (I completely distrust relativism, by the way). What we have, on the contrary, is an ample set of values and truths, of life standards and forms of interpreting reality. In fact, today we do not have one singular unique reality - in any way.

Science is much vivid large field, and within the social sciences great advances are being made - and certainly not along the way of the debate "modernism vs postmodernism".

Let's, f.i, focus on the computational social sciences, or also on the non-equilibroum social sciences, or even on the movement for anti-utilitarian social sciences (MAUSS)...

I can see a significant difference between the two periods, in the former, people were more actively engaged with securing their present and future ends, be it with regard to their own future, for their posterity,  for a rainy day and of course were more involved with striking balance between their earnings and social standing.  Contrary to it, in post modern era, people have started living in present, they are least bothered about their rainy day, they drag more pleasure in wrong doings, and those who have secured their future ends in modern era are more lavish in their life style. 

In mine view the post modern characters are more confused to take decission like us than the modern. Like a post modern character of any film Batman: he decides when trouble comes. Whereas, Modern Characters are more like struggling characters who do things despite the world is against them. For eg: from albert Camus Myth of sisyphus

Hi ha una dita castellana que diu que tot és segons el color del cristall amb que hom mira. També recomanaria una tesi doctoral sobre la relativitat del relativisme en Diderot, per exemple. I així podríem continuar fins a mossegar-nos la cua

francesc (espinet)

This is very interesting question. When relativism says "there is no truth" and the truth says "relativism does not make sense", Postmodernism defines it as "there are many truths" and all of them are accurate or potentially can be. For instance, the answer to the question "is faith in God a good or a bad thing". For a believer, the true answer is "good" and for the atheist it is "bad". In Postmodernism there are many truths and none of them is the absolute one, the context determines the answer. Philosophically e.c. Aristotle) it is not acceptable conception, but practically it works and manifests itself in a form of religious tolerance. Please look at the article below, it develops well this problem as well

Article The Postmodern Terms – Postmodernity and Postmodernism