Jean-Baptiste Lamarck and the Place of Irritability in the History of Life and Death

Abstract

In the history of philosophy and science, vitalism has a bad reputation, for the very definition of life remains remorselessly murky. And yet life also resists all attempts at reduction carried out by the logic of mechanical reason. While on a superficial level, life smacks of irrational exuberance, on a deeper level, it is in the very uncomfortable company of death. In this chapter, I argue that this ambivalence is particularly evident in Jean-Baptiste Lamarck’s natural philosophy. In his chemical, geological, botanical and zoological views, Lamarck advocated a theory of decaying rather than living matter. He characterized orgasm, irritability and sensibility – the forms which life takes on in the physical universe– as momentary interruptions of nature’s ordinary course toward death and destruction. This chapter examines Lamarck’s notion of irritability, paying special attention to his concept of “intussusception.” By intussusception, Lamarck meant a universal mechanism of organic mutability through which organisms were able to calibrate their reactions to the environment. He argued that through increasingly more complex reactions, living beings could resist the universal tendency to disintegration and breakup by internalizing pressures coming from the environment.