Scientific positivism was one of the most influential ideologies of progress in the early modern period and had a powerful impact on the formation of popular educational movements in the 19th century in Europe. This paper considers the form it took in France, probably the most sophisticated example, which itself influenced other European movements. It traces, briefly, the rise of positivism from Bacon through the Scottish Enlightenment philosophers to Auguste Comte and then considers how this movement found an educational vehicle in, firstly, the French Grand-Orient organization of freemasonry and then through the universités populaires. It is argued that the strength of the movement was in its resistance to authoritarian epistemologies, in particular clericalism, and in its commitment to learning based on individual experience and experimentation. In France, it becomes adopted by the Radical Party, led by Jules Ferry, as an official ideology for reforming education having first been widely diffused through Masonic educational organizations. It informs a 'third way' politics opposed both to laissez faire capitalism and revolutionary Marxism offering an apparently 'scientific' neutrality. The study demonstrates the importance of freemasonry as a vehicle for popular educational movements in the 19th century and the notions of class harmony it promoted, which underpinned the foundations of the newly emerging welfare state.