a. A doctrine contending that sense perceptions are the only admissible basis of human knowledge and precise thought.

b. The application of this doctrine in logic, epistemology, and ethics.

c. The system of Auguste Comte designed to supersede theology and metaphysics and depending on a hierarchy of the sciences, beginning with mathematics and culminating in sociology.

d. Any of several doctrines or viewpoints, often similar to Comte's, that stress attention to actual practice over consideration of what is ideal: "Positivism became the 'scientific' base for authoritarian politics, especially in Mexico and Brazil" (Raymond Carr).