About the creation-evolution controversy, Popper wrote that he considered it "a somewhat sensational clash between a brilliant scientific hypothesis concerning the history of the various species of animals and plants on earth, and an older metaphysical theory which, incidentally, happened to be part of an established religious belief" with a footnote to the effect that "[he] agree[s] with Professor C.E. Raven when, in his Science, Religion, and the Future, 1943, he calls this conflict "a storm in a Victorian tea-cup"; though the force of this remark is perhaps a little impaired by the attention he pays to the vapours still emerging from the cup—to the Great Systems of Evolutionist Philosophy, produced by Bergson, Whitehead, Smuts, and others."