Descartes – Empiricism is unreliable because our senses may misinform us Essay Example

Western philosophy:3. 'I think, therefore I am.'The famous Cartesian cogito, ergo sum. This was Descartes' "Archimedian fulcrum," the single fixed point of certainty by which he believed he could move out of his world of doubt. This was his "eureka," his "open sesame" to a philosophy and science of certitude. However, momentous as this discovery was, he still had a long way to go.

He had established that he was, but what was he? Since he had already rejected that he was his body or any material thing, all that was left to conclude (he believed) was:4. 'I am a thinking thing.'The self is a thinking substance-res cogitans-without extension or materiality (which are the attributes of bodies). Descartes had now established that he existed as mind distinct from any extended body-res extensa. And with this distinction-the infamous "Cartesian mind-body dualism"-the fate of Western philosophy, science and medicine was set for the best part of the next four hundred years.Having established to his satisfaction the reality of his subjective self as "thinking substance," a major difficulty now confronted him: "How do I establish the existence of an external world?" It was one thing to wipe the slate clean and discover a conscious self as an indubitable point of certainty in a sea of doubt; it would be another thing to move beyond the barrier of this solipsist cogito.

Pursuing the trail of his deductive logic, Descartes reasoned that since he existed as a thinking substance that doubts, and since doubting is less perfect than knowing, he must be less than perfect. His next move was to conclude:5. 'I am not a perfect being.'And this posed a puzzle:

How is it that an imperfect being can have a idea of "perfection"? Where did that notion come from? Examining the contents of his mind he discovered a clear and distinct idea of "perfection." But since what is imperfect cannot cause what is perfect, and having established his own imperfection, he concluded that the cause of perfection must be something other than who or what he was. The cause must be external.

And with this, the magic of rationalism burst through the solipsist bubble and created an opening for "other."6. 'The cause of perfection is external to my self.'For his next move, Descartes revealed his medieval "stuckness" by appealing to the Scholastic arguments for the existence of God.

Like Bacon, Descartes was a pioneer braving the transition from the medieval world of the Church, a world steeped in Thomism, Augustinianism, and Aristotelianism. However, he emerged from that world still dripping with the metaphysical assumptions of his age. He was amphibian: leaving the deep waters of Scholasticism for the shallows of modernism, but remaining a creature adapted to both worlds. Clinging to him were strands of the old paradigm, such as the "Cosmological Argument" that proposed the idea of a Perfect Being could be caused only by a Perfect Being, and the "Ontological Argument" that the very essence of Perfect Being is that it necessarily exists.Given these hand-me-down metaphysical assumptions, Descartes believed he had proved the existence of God as a direct result of his initial cogito. He believed he had established, on rational grounds, the existence of a Perfect Being external to his own thinking substance.

However, Descartes' revolutionary rational method was flawed-infected by traces

of the very superstition he believed he was replacing. He reasoned:7. 'God, being perfect, assures the veracity of "clear and distinct" reason.'God, a Perfect Being, perfectly benevolent would not deceive. He would not endow his creatures with a capacity for "clear and distinct" ideas yet maliciously make these ideas false.

Therefore, the existence of God guarantees the correspondence between the ideas and the objects of reason. Reason was pure, given to humans by God. Error, according to Descartes, results from inappropriate exercise of free-will, which may choose to assent to judgments composed of confused ideas and/or to those resting on unquestioned evidence of the senses.By this stage, Descartes' method had succeeded in establishing the existence of the subjective self-an internal thinking thing-and an external God.

What about the world of Nature? How could humans know the external world-the world of extended substance, of material things, the world of natural science-including his own body? Well, given the previous steps in his method, the rest was now relatively easy:8. 'We can know the natural world of external, extended things by the correct application of reason.'Reason, pure and innate, given to man by God, applied with the precision of geometry and mathematics to extended substances, would lead the human mind to certainty about the world. Descartes believed his method laid the foundations for a reliable science of nature, based on mathematical reasoning. Mathematical physics, Descartes believed, discloses the truth of the properties of bodies in motion, of objects in space (res extensa).