 Kant’s work was influential among those studying biological phenomena, even if misinterpreted in various ways, and helped frame the question of teleology versus mechanism in the early 19th century (Lenoir 1982). His discussion stressed the significance of methodological conclusions—it is necessary (a maxim or regulative principle) to take organisms as natural purposes if we are to investigate them scientifically. This encouraged speculations about new forces, akin to those found in Newtonian mechanics, which would explain biological phenomena “mechanistically” (e.g., the formative force explaining embryonic development; see Look 2006, Richards 2000). The Newtonian inspiration survived, with or without Kantian traces, well into the 19th century and beyond. Comparative anatomy (conceptualized broadly to include functional anatomy and embryology) exploited methodological suggestions from successful physical science. For example, Geoffroy St. Hilaire appealed to Newton’s musings that animals are governed by similar principles or laws as those found in mechanics (Le Guyader 2004). More typical is Richard Owen’s discussion of matter and its properties within living organisms, where he exhibits a clear anti-reductionist stance and postulates something akin to emergent  properties.[4]  This perspective was shared by many comparative anatomists who used an “analysis:synthesis” style of reasoning (Elwick 2007). A related strand regarding reductionism winds its way through physiological investigations of the 19th century. Here the Cartesian mechanical-reductionist program is rejoined with an emphasis on the animal machine (Canguilhem in Delaporte 1994, ch. 5, 8, 10, 12; Coleman 1977, ch. 6). Despite clear metaphysical commitments to a form of ontological reduction, methodological types of reductionism were qualified because of their impact on experimental design (e.g., Bernard 1957 [1865]). Overall, there was a diversity of mechanist (“reductionist”) and organicist (“non-reductionist”) positions corresponding to ontological, epistemic, and methodological types of reduction in the 19th century, similar to the philosophical diversity observable today (see Sections  3  and  5  below).