What did it mean to adopt a chancy or mathematical perspective on evolutionary theory? I’ll consider this question by examining the claim that from around 1900 to 1920, a broadly morphological, non-mathematical, Mendelian picture of evolution had carried the day. I’ll argue that certain tenets of the biometrical view can be readily detected in the textbook tradition of this period, and thus that a continuity of philosophical approach, rather than a series of historical ruptures, better captures the nature of this pivotal period in evolution’s history.