Writing in 2002, the co-founder of modern evolutionary synthesis, Ernst Mayr, acclaimed, 'When one reads the writing of one of the leading vitalists like Driesch, one is forced to agree with him'. Mayr pointed out that Hans Driesch, biologist, philosopher, theologian, was one of the central figures who helped end the belief in organisms as machines. Vitalism, the views of which Driesch articulated, understood that nuclear division and embryo development cannot solely be accounted for by physiochemical processes. There must be a self-determining force, a vital spark.