The concept of progress is linked to the vision of history as a perception of the emergence and development of human actions.
Since its beginning, sociology defined progress not as a evaluative concept, but as the gradual and unavoidable deployment of human capacities (Comte). This meaning was clearly influenced by the growing Western civilisation that assumed progress as an increasingly sophistication of scientific knowledge and the improving quality of life.
This concept of progress was based on evolutionary theories and perspectives (social dynamics - Comte; social evolution - Spencer; social development - Marx and Engels), following the culture of the nineteenth century (optimistic, rationalistic and materialistic).
It seems nowadays more evident than in previous ages that the historical process should be seen as fragmented and discontinuous series of events, linked not by necessity but by accidents and coincidences rather than a monotonous and continuos deployment of successive events.
This new vision is clearly influenced by at least three key-elements, the failure of science to create a sort of moral utopia valuable for all humanity, the emergence of doubt, the abrupt explosion of the environmental dimension.