© koninklijke brill nv, leiden,  | doi: ./- Aries – Journal for the Study of Western Esotericism  () – ARIES brill.com/arie Blavatsky and the Lives Sciences Julie Chajes Tel Aviv University juliechajes@gmail.com Abstract This article considers how the matriarch of the Theosophical Society, Helena Petro- vna Blavatsky (1831–1891) constructed the category “science,” situating this construal within a world in which the boundaries of “legitimate” science were more contested than they are today. Focusing on her teachings on rebirth, the article demonstrates that Blavatsky’s doctrines owe a considerable debt to the scientific theories under discus- sion at her time of writing. It explores her debt to the controversial physicists Balfour Stewart (1828–1887) and Peter Guthrie Tait (1831–1909), her hostility towards the popu- lar materialist monism of Ernst Haeckel (1834–1919), her hatred of Darwinism, and her preference for theories of evolution influenced by German Romanticism, such as the progressivist versions of orthogenesis proposed by CarlWilhelm von Nägeli (1817–1891), Karl Ernst von Baer (1792–1876), and Darwin’s nemesis, Richard Owen (1804–1892). Keywords Helena Blavatsky – Theosophy – reincarnation – nineteenth-century science – evolu- tion – The Unseen Universe – Ernst Haeckel – Darwinism – orthogenesis – recapitula- tionism – German Romanticism – materialism Introduction This article contributes to a cultural history of Theosophy and of the nine- teenth century more generally by contextualising the rebirth theories of Helena Petrovna Blavatsky (1831–1891) in contemporaneous scientific developments. 1 For an introduction to Blavatsky and Science, see Hammer, Claiming Knowledge, 218–222 and