Descartes

Rene Descartes (1596 – 1650) lived during an intellectually vibrant time. European scholars had supplemented Catholic doctrine with a tradition of Aristotle scholarship, and early scientists like Galileo and Copernicus had challenged the orthodox views of the Scholastics. Surrounded by conflicting yet seemingly authoritative views on many issues, Descartes wants to find a firm foundation on which certain knowledge can be built and doubts can be put to rest. So he proposes to question any belief he has that could possibly turn out to be false and then to methodically reason from the remaining certain foundation of beliefs with the hope of reconstructing a secure structure of knowledge where the truth of each belief is ultimately guaranteed by careful inferences from his foundation of certain beliefs.

When faith and dogma dominate the intellectual scene, “How do we know?” is something of a forbidden question. Descartes dared to ask this question while the influence of Catholic faith was still quite strong. He was apparently a sincere Catholic believer, and he thought his reason-based philosophy supported the main tenants of Catholicism. Still he roused the suspicion of religious leaders by granting reason authority in the justification of our beliefs.

Descartes is considered by many to be the founder of modern philosophy. He was also an important mathematician and he made significant contributions to the science of optics. You might have heard of Cartesian coordinates. Thank Descartes. Very few contemporary philosophers hold the philosophical views Descartes held. His significance lays in the way he broke with prior tradition and the questions he raised in doing so. Descartes frames some of the big issues philosophers continue to work on today. Notable among these are the foundations of knowledge, the nature of mind, and the question of free will. We’ll look briefly at these three areas of influence before taking up a closer examination of Descartes’ philosophy through his Meditations of First Philosophy.

To ask “How do we know?” is to ask for reasons that justify our belief in the things we think we know. Descartes’ Meditations provide a classic example of the epistemological project of providing systematic justification for the things we take ourselves to know, and this remains a central endeavor in epistemology. This project carries with it the significant risk of finding that we lack justification for things we think we know. This is the problem of skepticism. Skepticism is the view that we can’t know. Skepticism comes in many forms depending on just what we doubt we can know. While Descartes hoped to provide solid justification for many of his beliefs, his project of providing a rational reconstruction of knowledge fails at a key point early on. The unintended result of his epistemological project is known as the problem of Cartesian skepticism. We will explain this problem a bit later in this chapter.

Another area where Descartes has been influential is in the philosophy of mind. Descartes defends a metaphysical view known as dualism that remains popular among many religious believers. According to this view, the world is made up of two fundamentally different kinds of substance, matter and spirit (or mind). Material stuff occupies space and time and is subject to strictly deterministic laws of nature. But spiritual things, minds, are immaterial, exist eternally, and have free will. If dualism reminds you of Plato’s theory of the Forms, this would not be accidental. Descartes thinks his rationalist philosophy validates Catholic doctrine and this in turn was highly influenced by Plato through St. Augustine.

The intractable problem for Descartes’ dualism is that if mind and matter are so different in nature, then it is hard to see how they could interact at all. And yet when I look out the window, an image of trees and sky affects my mind. When I will to go for a walk, my material body does so under the influence of my mind. This problem of mind-body interaction was famously and forcefully raised by one of the all too rare female philosophers of the time, princess Elisabeth of Bohemia.

A whole branch of philosophy, the philosophy of mind, is launched in the wake of problems for substance dualism. Today, the philosophy of mind is merging with neuroscience, cognitive psychology, and information science to create a new science of mind. We are rapidly learning how material brains realize the processes of thought. Once again, Descartes has failed in a most fruitful way. We also see how undeserved philosophy’s reputation for failing to answer its questions is. While many distinctively philosophical issues concerning the mind remain, the credit for progress will go largely to the newly minted science of mind. The history of philosophy nicely illustrates how parenthood can be such worthwhile but thankless work. As soon as you produce something of real value, it takes credit for itself….