Progress can broadly be defined as movement in a desirable direction. As such it is not something that be proved. Some will define a progressive society as one where every person will have the opportunity to develop the full potentials of which each of them is capable. And, therefore, social progress is when there is more personal freedom, better health, less discrimination.
There are other kinds
economic progressless poverty, higher standards of living
technological progressinventions, processes and techniques that make life easier and richer
moral or ethical progressmore justice, compassion, less criminal activity
scientific progress an increase in the understanding of the world
Modern human progress would include all of these and more.
The ancients did not form the idea of progress because they did not see change for the better in their lifetimes. Medieval Christian theology, in a sense, was forward looking because it established the concept of the past leading toward a desirable future goal.
In the Renaissance self-confidence restored in human reason and life on earth was recognized as having value independent of connection with the hereafter.
Some people, misreading the science, view evolution as progressive. The idea of human perfectibility and the idea of progress as an increase in human freedoms are key concepts of modern society.