This idea of a special science (not the humanities, not metaphysics) for the social was prominent in the 19th century and not unique to Comte. It has recently been discovered that the term "sociology" (as a term considered coined by Comte) had already been introduced in 1780, albeit with a different meaning, by the French Essayist Emmanuel Joseph Sieyès (1748–1836). The ambitious (or many would say 'grandiose') way that Comte conceived of this special science of the social, however, was unique. Comte saw this new science, sociology, as the last and greatest of all sciences, one which would include all other sciences and integrate and relate their findings into a cohesive whole. It has to be pointed out, however, that he noted a seventh science, one even greater than sociology. Namely, Comte considered "Anthropology, or true science of Man [to be] the last gradation in the Grand Hierarchy of Abstract Science."

Comte's stages were (1) the theological stage, (2) the metaphysical stage, and (3) the positive stage. (1) The Theological stage was seen from the perspective of 19th century France as preceding the Age of Enlightenment, in which man's place in society and society's restrictions upon man were referenced to God. Man blindly believed in whatever he was taught by his ancestors. He believed in a supernatural power. Fetishism played a significant role during this time. (2) By the "Metaphysical" stage, Comte referred not to the Metaphysics of Aristotle or other ancient Greek Philosophers. Rather, the idea was rooted in the problems of French society subsequent to the French Revolution of 1789. This Metaphysical stage involved the justification of universal rights as being on a vauntedly higher plane than the authority of any human ruler to countermand, although said rights were not referenced to the sacred beyond mere metaphor. This stage is known as the stage of investigation, because people started reasoning and questioning, although no solid evidence was laid. The stage of investigation was the beginning of a world that questioned authority and religion. (3) In the Scientific stage, which came into being after the failure of the revolution and of Napoleon, people could find solutions to social problems and bring them into force despite the proclamations of human rights or prophecy of the will of God. Science started to answer questions in full stretch. In this regard he was similar to Karl Marx and Jeremy Bentham. For its time, this idea of a Scientific stage was considered up-to-date, although from a later standpoint, it is too derivative of classical physics and academic history. Comte's law of three stages was one of the first theories of social evolutionism.

Auguste Comte was born in Montpellier, Hérault on 19 January 1798. After attending the Lycée Joffre and then the University of Montpellier, Comte was admitted to the École Polytechnique in Paris. The École Polytechnique was notable for its adherence to the French ideals of republicanism and progress. The École closed in 1816 for reorganization, however, and Comte continued his studies at the medical school at Montpellier. When the École Polytechnique reopened, he did not request readmission.

The final, most evolved stage is the positivist stage, the stage when humans give up on discovering absolute truth, and turn towards discovering, through reasoning and observation, actual laws of phenomena. Humans realize that laws exist, and that the world can be rationally explained through science, rational thought, laws, and observation. Comte was a positivist, believing in the natural rather than the supernatural, and so he claimed that his time period, the 1800s, was in the positivist stage. He believed that within this stage, there is a hierarchy of sciences: mathematics, astronomy, terrestrial physics, chemistry, and physiology. Mathematics, the “science that relates to the measurement of magnitudes”, is the most perfect science of all, and is applied to the most important laws of the universe. Astronomy is the most simple science, and is the first “to be subjected to positive theories". Physics is less satisfactory than astronomy, because it is more complex, having less pure and systemized theories. Physics, as well as chemistry, are the “general laws of the inorganic world”, and are harder to distinguish. Physiology completes the system of natural sciences, and is the most important of all sciences because it is the “only solid basis of the social reorganization that must terminate the crisis in which the most civilized nations have found themselves”. This stage will fix the problems in current nations, allowing progression and peace.

Following his return to Montpellier, Comte soon came to see unbridgeable differences with his Catholic and monarchist family and set off again for Paris, earning money by small jobs. In August 1817 he found an apartment at 36 rue Bonaparte in Paris' 6ème (where he lived until 1822) and later that year he became a student and secretary to Henri de Saint-Simon, who brought Comte into contact with intellectual society and greatly influenced his thought therefrom. During that time Comte published his first essays in the various publications headed by Saint-Simon, L'Industrie, Le Politique, and L'Organisateur (Charles Dunoyer and Charles Comte's Le Censeur Européen), although he would not publish under his own name until 1819's "La séparation générale entre les opinions et les désirs" ("The general separation of opinions and desires"). In 1824, Comte left Saint-Simon, again because of unbridgeable differences. Comte published a Plan de travaux scientifiques nécessaires pour réorganiser la société (1822) (Plan of scientific studies necessary for the reorganization of society). But he failed to get an academic post. His day-to-day life depended on sponsors and financial help from friends. Debates rage as to how much Comte appropriated the work of Saint-Simon.

Comte married Caroline Massin in 1825. In 1826, he was taken to a mental health hospital, but left without being cured – only stabilized by French alienist Jean-Étienne Dominique Esquirol – so that he could work again on his plan (he would later attempt suicide in 1827 by jumping off the Pont des Arts). In the time between this and their divorce in 1842, he published the six volumes of his Cours.

Comte first described the epistemological perspective of positivism in The Course in Positive Philosophy, a series of texts published between 1830 and 1842. These texts were followed by the 1848 work, A General View of Positivism (published in English in 1865). The first three volumes of the Course dealt chiefly with the physical sciences already in existence (mathematics, astronomy, physics, chemistry, biology), whereas the latter two emphasised the inevitable coming of social science. Observing the circular dependence of theory and observation in science, and classifying the sciences in this way, Comte may be regarded as the first Philosopher of science in the modern sense of the term. Comte was also the first to distinguish natural philosophy from science explicitly. For him, the physical sciences had necessarily to arrive first, before humanity could adequately channel its efforts into the most challenging and complex "Queen science" of human society itself. His work View of Positivism would therefore set out to define, in more detail, the empirical goals of sociological method.

Comte developed a close friendship with John Stuart Mill. From 1844, he fell deeply in love with the Catholic Clotilde de Vaux, although because she was not divorced from her first husband, their love was never consummated. After her death in 1846 this love became quasi-religious, and Comte, working closely with Mill (who was refining his own such system) developed a new "Religion of Humanity". John Kells Ingram, an adherent of Comte, visited him in Paris in 1855.

In later years, Comte developed the 'religion of humanity' for positivist societies in order to fulfil the cohesive function once held by traditional worship. In 1849, he proposed a calendar reform called the 'positivist calendar'. For close associate John Stuart Mill, it was possible to distinguish between a "good Comte" (the author of the Course in Positive Philosophy) and a "bad Comte" (the author of the secular-religious system). The system was unsuccessful but met with the publication of Darwin's On the Origin of Species (1859) to influence the proliferation of various Secular Humanist organizations in the 19th century, especially through the work of secularists such as George Holyoake and Richard Congreve. Although Comte's English followers, including George Eliot and Harriet Martineau, for the most part rejected the full gloomy panoply of his system, they liked the idea of a religion of humanity and his injunction to "vivre pour autrui" ("live for others"), from which comes the word "altruism".

He published four volumes of Système de politique positive (1851–1854). His final work, the first volume of La Synthèse Subjective ("The Subjective Synthesis"), was published in 1856.

Comte's explanation of the Positive philosophy introduced the important relationship between theory, practice and human understanding of the world. On page 27 of the 1855 printing of Harriet Martineau's translation of The Positive Philosophy of Auguste Comte, we see his observation that, "If it is true that every theory must be based upon observed facts, it is equally true that facts can not be observed without the guidance of some theories. Without such guidance, our facts would be desultory and fruitless; we could not retain them: for the most part we could not even perceive them."

Comte died in Paris on 5 September 1857 from stomach cancer and was buried in the famous Père Lachaise Cemetery, surrounded by cenotaphs in memory of his mother, Rosalie Boyer, and of Clotilde de Vaux. His apartment from 1841–1857 is now conserved as the Maison d'Auguste Comte and is located at 10 rue Monsieur-le-Prince, in Paris' 6th arrondissement.

Comte's fame today owes in part to Émile Littré, who founded The Positivist Review in 1867. Debates continue to rage, however, as to how much Comte appropriated from the work of his mentor, Henri de Saint-Simon.

"The law is this: that each of our leading conceptions – each branch of our knowledge – passes successively through three different theoretical conditions: the Theological, or fictitious; the Metaphysical, or abstract; and the Scientific, or positive." — A. Comte

Comte's social theories culminated in his "Religion of Humanity", which presaged the development of non-theistic religious humanist and secular humanist organizations in the 19th century. Comte may have coined the word altruisme (altruism).