Progress is the idea that advances in technology, science, and social organization can produce an improvement in the human condition, and therefore that entire societies, and humanity in general, can improve in terms of their social, political, and economic structures. This may happen as a result of direct human action, as in social enterprise or through activism, or as a natural part of sociocultural evolution.
The concept of progress was introduced in the early 19th century social theories, especially social evolution as described by Auguste Comte and Herbert Spencer. It was present in the Enlightenment's philosophies of history. As a goal, social progress has been advocated by varying realms of political ideologies with different theories on how it is to be achieved.
Scientific progress is the idea that the scientific community learns more over time, which causes a body of scientific knowledge to accumulate. The chemists in the 19th century knew less about chemistry than the chemists in the 20th century, and they in turn knew less than the chemists in the 21st century. Looking forward, today's chemists reasonably expect that chemists in future centuries will know more than they do.
This process differs from non-science fields, such as human languages or history: the people who spoke a now-extinct language, or who lived through a historical time period, can be said to have known different things from the scholars who studied it later, but they cannot be said to know less about their lives than the modern scholars. Some valid knowledge is lost through the passage of time, and other knowledge is gained, with the result that the non-science fields do not make scientific progress towards understanding their subject areas.
From the 18th century through late 20th century, the history of science, especially of the physical and biological sciences, was often presented as a progressive accumulation of knowledge, in which true theories replaced false beliefs. Some more recent historical interpretations, such as those of Thomas Kuhn, tend to portray the history of science in terms of competing paradigms or conceptual systems in a wider matrix of intellectual, cultural, economic and political trends. These interpretations, however, have met with opposition for they also portray the history of science as an incoherent system of incommensurable paradigms, not leading to any scientific progress, but only to the illusion of progress.