First Impressions and Ideas

For this semester I’ll offer my reflections on an introductory, freshmen-level course on western core texts that I am teaching.

This past week we read excerpts from René Descartes’ Discourses on Method and John Locke’s Essay Concerning Human Understanding as an introduction to modernity. The skepticism of Descartes – cogito, ergo sum – not only rejected religion as a source of certain knowledge but also sowed the seeds of rationalism. Later Locke rejected rationalism and instead advocated for empiricism as the preferred modern epistemology. These two schools of thought, rationalism and empiricism, emerged as the two dominant modes of knowledge in the West.

Descartes began by dividing reality into the res cogitans (the thinking substance) and res extensa (the extended substance). The former was characterized by intelligence, mind, and consciousness; the latter constituted the external world. This division of reality brought the problem of epistemology to the forefront: how can we, the res cogitans, know the world, the res extensa? How can a wish that belonged to the res cogitans initiate a movement in the res extensa? And how can an object in the res extensa be known to the res cogitans?

For Descartes the res cogitans and res extensa connected in the pineal gland in humans where they met mysteriously through the work of a third substance, God. Regardless of whether one agrees with Descartes’ solution, the problem of knowledge still persisted between the res cogitans and res extensa. Descartes therefore postulated that the qualities in the res cogitans corresponded to similar qualities in the res extensa; or what he called ideae innatae (innate ideas). These qualities in the res cogitans included time, space, movement, number, figure, and magnitude. Thus, the innate idea of circle that existed in our res cogitans corresponded to the same object in the res extensa, thereby making knowledge possible.

Descartes’ doctrine of ideae innatae prompted the empiricists, such as Locke, not only to object to it but to propose an alternative account. For Locke, there was no ideae innatae but rather all knowledge of the external world was a result of experience by means of the senses. Through a process of sensation and reflection, we have imprinted upon our minds simple ideas that we later construct into complex and abstract ones. Ever since this time, there have been two schools of thought: the rationalistic school that proclaimed the sufficiency and power of the mind to understand the world and the empiricist school that denied such sufficiency and power and instead relied on the capacity of our senses.

While they disagreed on how one acquires knowledge, both accepted the premise that reality was divided into a res cogitans and res extensa. This is different from the classical and medieval perspective where such a division did not exist: humans participated with rather than being detached from reality. There was no Archimedean point where one could objectively observe the world; and, hence, there was no aspiration to know all of reality.

With postmodernity, we live in the remnants of a world once defined by rationalism and empiricism. Although these schools of thought still have staying power in the natural sciences and mathematics – and their practical vocational children, like engineering, medicine, and computer science – rationalism and empiricism in the humanities and social sciences have been supplanted by the irrationalism of postmodernity. This replacement in turn has spilled over into our culture and politics where a “school of suspicion” is now prevalent, resulting political polarization and violence. A return to rationalism and empiricism, or something older, might restore a sense of stability in our account of knowledge, culture, and politics. Thus the need to revisit Descartes and Locke for our students today.