René Descartes (1596-1650; pronounced “day-CART”) is rightly considered the “father” of modern philosophy. But he also had a massive impact on mathematics, inventing the Cartesian coordinate system of x’s and y’s that every high school student learns. He was a devout Roman Catholic, although the church of his day condemned his physics and philosophy. He was French but did most of his work in the Netherlands, most importantly a work called, Discourse on Method. At the time of his death he was a tutor to Queen Christina of Sweden.
Every philosopher to some extent gives expression to the struggles and spirit (Zeitgeist) of their time. The most famous thinkers are those whose expressions and solutions most resonate with their age or some later one. That to which Descartes gave expression was a sense of uncertainty and a thirst for something solid and true. The Protestant Reformation and the Renaissance had generally eroded the assumptions of a thousand years; in particular, that the things Christians had heard and believed through the Church were correct. Those who were convinced that charismatic leaders like Martin Luther, John Calvin, or Huldrych Zwingli had correctly interpreted the Bible might simply switch the source of their certainty. But what had been an unquestioned assumption (Christian belief is self-evident and universally agreed) now had to be argued for.
The beginnings of the scientific revolution would become yet another source of questioning assumptions. We discussed Francis Bacon (1561-1626) in chapter 8 and his attempts to place the quest for knowledge on an experimental basis. One gathers evidence and tabulates the data, eventually drawing the conclusion that best fits the evidence. Again, he represents a move from assumption of truth to the need to justify it.
In this context, Descartes begins to look for a place of absolute certainty from which to establish a firm basis for truth. Unlike Bacon, he is a rationalist (see chapter 4). He searches for truth first in reason. He questions everything he can question and finds he can doubt everything except for the fact that he is doubting. His conclusion is, cogito ergo sum, “I think; therefore, I am.” From this point of certainty, he then proceeds to try to reconstruct certainty on all the things people of his day took for granted, including the existence of God.
Despite how certain Descartes himself might be of his conclusions, he has sowed a doubt that had not been there before, much as the Reformation did. All the ordinary truths about the world—that I am really sitting somewhere reading this book—now have a question mark over them that was not there before. He creates a new sort of human identity. “I” am the most certain thing I can know, and the rest of the world is the object of my knowledge. I may still believe in God, but it is I who is doing the deciding and believing. The order of the world, all the truths that I had once assumed without question, are now truth claims that I am forced to make decisions about. Even faith becomes an inevitable choice I have to make as an individual, instead of an assumption. The shift seems inevitable. I can still believe everything I believed before about God, faith, and the world, and I can believe them ferociously. But I am now keenly aware that I am the one doing the believing.
The impact of this shift, this turn of focus of truth from something “out there” inherent in the world to something I have to make judgments on inside my head, has been far beyond massive. This sense of a human individual as a rational being that makes decisions about what is true has empowered everything from the scientific revolution to the birth of capitalism to the notion of social contracts between individuals, the basis for the United States system of government. Descartes inadvertently gives birth to the “autonomous individual,” a sense of a human person as someone who can make objective decisions about the quite distinct world outside of herself.
Descartes’ sense of nature and of the soul fit hand in glove with his other ideas. He makes a sharp distinction between the natural world and now the super-natural world. Nature is no longer everything that God created, but only now the physical, material part of it. Descartes does not include things of God, angels, or spirits, or things having to do with the mind in what he calls "nature." These now "immaterial" things are far more certain to him than what would become the world of science. He thus inadvertently prepared the way for Deism, which saw the world as a machine God created but with which He need no longer be involved.
Descartes also shifts the soul from being the life principle of a person to become the immaterial container in which the human self resides. It is where the “I” can think about the world in a detached and objective fashion. It is where the human will is located. It is the part of the person that survives death, like an escape pod.
The current climate is rather negative toward Descartes, and clearly we can point out any number of extremes in his thinking. Martin Heidegger (1886-1976), more than anyone, has shown that we cannot detach ourselves from the world around us. Almost everyone today would recognize the impossibility of complete objectivity. Nevertheless, we should not forget that most of the greatest cultural developments in the Western world these last few centuries can be traced back to Descartes more than to any other single individual.