Positivism is the view that the only authentic knowledge is scientific knowledge, and that such knowledge can only come from positive affirmation of theories through strict scientific method (techniques for investigating phenomena based on gathering observable, empirical and measurable evidence, subject to specific principles of reasoning). The doctrine was developed in the mid-19th Century by the French sociologist and philospher Auguste Comte (1798 - 1857).

The term "positive" in the epistemological sense indicates a "value-free" or objective approach to the study of humanity that shares much in common with methods employed in the natural sciences, as contrasted with "normative", which is indicative of how things should or ought to be.

Comte saw the scientific method as replacing Metaphysics in the history of thought and Philosophy of Science. His Law of Three Stages (or Universal Rule) sees society as undergoing three progressive phases in its quest for the truth: the theological (where everything is referenced to God, and the divine will subsumes human rights); the metaphysical (the post-Enlightenment humanist period, where the universal rights of humanity are most important); and the positive (the final scientific stage, where individual rights are more important than the rule of any one person). Comte believed that Metaphysics and theology should be replaced by a hierarchy of sciences, from mathematics at the base to sociology at the top.

There are five main principles behind Positivism:

• The logic of inquiry is the same across all sciences (both social and natural).
• The goal of inquiry is to explain and predict, and thereby to discover necessary and sufficient conditions for any phenomenon.
• Research should be empirically observable with human senses, and should use inductive logic to develop statements that can be tested.
• Science is not the same as common sense, and researchers must be careful not to let common sense bias their research.
• Science should be judged by logic, and should be as value-free as possible. The ultimate goal of science is to produce knowledge, regardless of politics, morals, values, etc.

Positivism is closely connected to Naturalism, Reductionism and Verificationism, and it is very similar in its outlook to Scientism. Later, in the early 20th Century, it gave rise to the stricter and more radical doctrine of Logical Positivism. Positivism is opposed to the Constructivist belief that scientific knowledge is constructed by scientists, and therefore not discovered from the world through strict scientific method.

• Logical Positivism (or Logical Empiricism) is a school of philosophy that developed out of Positivism, and attempted to combine Empiricism (the idea that observational evidence is indispensable for knowledge of the world) with a version of Rationalism (the idea that our knowledge includes a component that is not derived from observation).
• Sociological Positivism is the view, developed from Auguste Comte's philosophical Positivism (see above), that the social sciences (as all other sciences) should observe strict empirical methods. Today, although many sociologists would agree that a scientific method is an important part of sociology, orthodox positivism is rare.
• Legal Positivism is a school of thought in Philosophy of Law which holds that laws are rules made (whether deliberately or unintentionally) by human beings, and that there is no inherent or necessary connection between the validity conditions of law and Ethics or morality. It stands in opposition to the concept of natural law (that there is an essential connection between law and justice or morality).
• Polish Positivism was a political movement in the late 19th Century, drawing its name and much of its ideology from Comte's philosophy (as well as from the works of British scholars and scientists). It advocated the exercise of reason before emotion, and argued that Polish independence from Russia, Germany and Austro-Hungary must be regained gradually from the ground up.