Foundations Of Cognitive Science


Descartes applied a highly skeptical method in an attempt to found a philosophy on incontestable truths.  This method established a key point: that thinking things exist, and do so independent  of the existence of an external world or a physical body.  Therefore a fundamental consequence of Descartes’ analysis was a profound division between mind and body – a philosophical position called dualism.  First, Descartes reasoned that mind and body must be composed of different ‘stuff’.  This had to be the case, because one could imagine that the body was divisible (e.g. through losing a limb) but that the mind was impossible to divide.  “Indeed the idea I have of the human mind, in so far as it is a thinking thing, which is not extended in length, breadth or height and has no other bodily characteristics, is much more distinct than the idea of any corporeal thing” (Descartes, 1641, p. 37).  Further to this, the mind was literally disembodied – the existence of the mind did not depend upon the existence of the body. “Accordingly this ‘I’, that is to say, the Soul by which I am what I am, is entirely distinct from the body and is even easier to know than the body; and would not stop being everything it is, even if the body were not to exist” (Descartes, 1637, p. 29).

Descartes used the creativity of language to provide another argument in support of dualism.  For Descartes, language-producing machines were inconceivable because machines were physical and therefore finite.  Their finite nature made it impossible for them to be infinitely variable.  “although such machines might do many things as well or even better than any of us, they would inevitably fail to do some others, by which we would discover that they did not act consciously, but only because their organs were disposed in a certain way” (Descartes, 1637, pp. 46-47).  In other words, the creativity of thought or language was only possible in the infinite, nonphysical, disembodied mind.


  1. Descartes, R. (1637/1960). Discourse On Method And Meditations. Indianapolis, IN: Bobbs-Merrill. (Originally published in 1637).
  2. Descartes, R. (1641/1996). Meditations On First Philosophy (Rev. ed.). New York: Cambridge University Press. (Originally published in 1641).

(Added September 2010)