Barnaby R. Hutchins

This chapter argues that the human perspective is not fully reducible – that is, that something would indeed be lost in the absence of the human perspective. It shows that epistemic subjectivity itself is an irreducible, ineliminable feature of the human standpoint. Subjectivity goes along with substantiality, and to be an epistemic subject is to be a substance with a mind. In E2p13, Spinoza identifies the mind's object with the body, thereby specifying where the multiplicity of epistemic subjects comes from – how, that is, individual epistemic subjects are identified and differentiated. The chapter looks at how the three kinds of knowledge relate to the notions of epistemic subjectivity. These include: imaginative knowledge; reason, or knowledge from common notions; and intuitive knowledge. Imaginative knowledge works straightforwardly on the model of having ideas in the thick sense.

A certain reading of Descartes, which we refer to as ‘the embodied Descartes’, is emerging from recent scholarship on L’Homme, in keeping with the interpretive trend which emphasizes Descartes’s identity as a natural philosopher. This reading complicates our understanding of Descartes’s philosophical project: far from strictly separating human minds from bodies, the embodied Descartes keeps them tightly integrated, while animal bodies behave in ways quite distinct from those of other pieces of extended substance. Here, we identify three categories of embodiment in contemporary readings of Descartes’s physiology: bodily health and function, embodied reflex and memory, and embodied cognition. All present more or less strong versions of the embodied Descartes. Together, they constitute a compelling reading of a Cartesian natural philosophy that, if not expressly antidualist, is an awfully long way from the canonical picture.

Descartes is usually taken to be a strict reductionist, and he frequently describes his work in reductionist terms. This dissertation, however, makes the case that he is a nonreductionist in certain areas of his philosophy and natural philosophy. This might seem like simple inconsistency, or a mismatch between Descartes's ambitions and his achievements. I argue that here it is more than that: nonreductionism is compatible with his wider commitments, and allowing for irreducibles increases the explanatory power of his system. Moreover, Descartes depends on nonreductionist knowledge and on irreducibles in order to maintain his epistemology and metaphysics. That is, there is more in the Cartesian world than mind, matter, and God.

I argue that Descartes explains physiology in terms of whole systems, and not in terms of the size, shape and motion of tiny corpuscles (corpuscular mechanics). It is a standard, entrenched view that Descartes’ proper means of explanation in the natural world is through strict reduction to corpuscular mechanics. This view is bolstered by a handful of corpuscular–mechanical explanations in Descartes’ physics, which have been taken to be representative of his treatment of all natural phenomena. However, Descartes’ explanations of the ‘principal parts’ of physiology do not follow the corpuscular–mechanical pattern. Des Chene has identified systems in Descartes’ account of physiology, but takes them ultimately to reduce down to the corpuscle level. I argue that they do not. Rather, Descartes maintains entire systems, with components selected from multiple levels of organization, in order to construct more complete explanations than corpuscular mechanics alone would allow.

At various points in his work on physiology and medicine, Descartes refers to a “principle of life.” The exact term changes—sometimes, it is the “principle of movement and life”, sometimes the “principle underlying all [the] functions” of the body —but the message seems consistent: the phenomena of living bodies are the product of a single, underlying principle. That principle is generally taken to be cardiac heat.1 The literature has, quite reasonably, taken this message at face value. Thus, Shapiro: “Descartes insists again and again that the human body is properly to be described as a machine whose workings are […] driven by the heat in the heart that...

I argue that Descartes is not a reductionist about life, but dissolves or eliminates the category entirely. This is surprising both because he repeatedly refers to the life of humans, animals, and plants and because he appears to rely on the category of life to construct his physiology and medicine. Various attempts have been made in the scholarship to attribute a principled concept of life to Descartes. Most recently, Detlefsen has argued that Descartes “is a reductionist with respect to explanation of life phenomena but not an eliminativist with respect to life itself”. I show that all these attempts either result in arbitrariness or force Descartes's wider philosophical project into incoherence. I argue that Descartes's ontological commitments make a principled concept of life impossible, that he does not need such a concept, and that his project ends up more coherent without one.