1. A doctrine or philosophical system that maintains that sense perceptions are the essential foundations of human erudition and precise thinking: Positivism is a way of thinking that consists of experimental investigation, scientific facts, and physical observations that are considered to be the primary sources of real knowledge.

Positivism declares that the only real knowledge is scientific knowledge, and that such cognizance can only come from positive affirmation of theories with a strict scientific method; in other words, a system of philosophy that accepts only things that can be seen or physically proven.

The modern usage of positivism indicates a lack of confidence in any speculation that is not controlled by factual data and sense experiences.

2. In jurisprudence or the system of laws, the view that any legal system is best studied by concentrating on the law of a specific system: The positivism of law includes the standards of conduct that are dictated by validly enacted laws, rather than by principles of natural law or by the nature of human beings.

A movement in philosophy that is devoted to unifying the sciences: Logical positivism primarily involves the creation of a unified terminology in which the statements of any science can be expressed and comprehended.