At the turn of the century (19th / 20th century), the reception of the zoologist Ernst Haeckel's (1834-1919) scientific monism was associated with the ambivalent attitude towards the entire Darwinist theory. The dissemination and reflection of Haeckel's monism in the Czech cultural area is documented, among other things, by (anti)monistic publications as well as by the correspondence of famous personalities of scientific and social life with Ernst Haeckel.
This is further illustrated by the work of a number of personalities from that period, such as the zoologist Theodor Novák, the physician Josef Bulova, the biologist and philosopher Emanuel Rádl, the philosopher František Krejčí or the politician František Václav Krejčí.