Post modernity and critical thinking

I recognise this may not be a very critically thought out statement or question but at the moment I am struggling to identify the difference between post modern approaches to issues and critical thinking. PM talks about questioning many basic assumptions, truth, our ability to assume or project answers to issues due to cultural formation issues, reader response and interpretation etc, but surely there is little difference between this and good critical thinking. I was always very skeptical of people asking if post modernity was real, but I am wondering if we more accurate in thinking in the shift as critical or (hyper or an extension of) modernity as wouldn’t critical thinking have it roots and be shaped by the science movement like modernity?