[2] After studying at the École Normale Supérieure, he received his doctorate in philosophy in 1901 with the theses The Platonic Theory of Knowledge and The Origins of Philosophical Radicalism.

[3] In an article of 1893, Halévy suggested that the great moral question of modern thought was how the abstract idea of duty could become a concrete aim of society.

He thoroughly explored the Jeremy Bentham manuscripts at Cambridge for his work on philosophical radicalism and over the years developed a deep and intensive knowledge of all the sources of 19th-century English history.

[5] "If economic facts explain the course taken by the human race," he wrote, "the England of the nineteenth century was surely, above all other countries, destined to revolution, both politically and religiously."

In lectures of 1929, revised in 1936 (published in 1938; The Era of Tyrannies), Halévy argued that the world war had increased national control over individual activities and opened the way for de facto socialism.

Wallas translates: The age of tyrannies dates from the month of August, 1914, that is to say from the time when the belligerent nations first adopted a form of social organisation which may be defined as follows:

That is the paradox of post-war Socialism.In what proved to be his last work (which he did not live to complete), Halévy began to bridge the gap between 1841 and 1895 with a volume entitled The Age of Peel and Cobden (1841-1852).