Positivism (derived from ponere, whence positus, that which is laid down, certain), a philosophical term, applied somewhat loosely to any system which confines itself to the data of experience and declines to recognize a priori or metaphysical speculations. In this sense the term may be applied to empirical philosophers in general. Thus Hume is a positivist in the sense that he specifically restricts philosophy to the sphere of observation, and regards the causal relation as being nothing more than what we have been accustomed to expect. Similarly Mill, Spencer and physical scientists generally view the universe from the positivist standpoint. In its commonest acceptation, however, positivism is both narrower and wider than this. The term is specifically used of the philosophy of Auguste Comte, who applied the term to his system according to which knowledge is based exclusively on the methods and discoveries of the physical or "positive" sciences. According to Comte human thought passes through three stages - theological, metaphysical and positive. The final stage, positivism, is the understanding of the universe not as composed of a multitude of individuals each with volition, but as an ordered organism governed by necessary laws (see further Comte). The outcome of this positivism is the substitution for revealed religion of a religion of humanity - according to Huxley "Catholicism minus Christianity" - in which God is replaced by Humanity. This religion was to have its special priesthood, ritual and organization.
Positivism has, therefore, two distinct sides, the philosophical and the religious or mystical. Philosophical positivism has had distinguished representatives in France, Germany and England, and in the wider sense indicated above may be regarded as one of the two or three chief influences on modern philosophical development. Though the details of Comte's philosophic structure, e.g. the classification of the sciences, are without important significance, the positivistic tendency is prominent in all systems of thought which deny the supernatural and the metaphysical. Agnosticism, Phenomenalism, Rationalism, Materialism all manifest the positivist spirit, denying what may be succinctly described as the metempirical.
In France the Comtian tradition was maintained with important reservations and the abandonment of the religious aspect by Littre (q.v.), Taine and others. In Germany many of the followers of Kant have in greater or less degree maintained the view that all true knowledge depends upon the observation of objective phenomena. The distinctly religious aspect has been comparatively unimportant, except in so far as modern social evolutionist ethics may be regarded as religious in character. In England, however, a number of prominent Positivists have carried out Comte's original ideal of a Church of Humanity with ritual and organization. The chief building (in Chapel Street, Lamb's Conduit Street, London) is adorned with busts of the saints of humanity, and regular services are held. Positivist hymns are sung and addresses delivered. Among the leaders of this movement have been Frederic Harrison, Richard Congreve, E. S. Beesly and J. H. Bridges (d. 1906). Services are also held weekly in Essex Hall, London, and there are a few other centres in the provinces, including a prosperous church in Liverpool.