René Descartes is often called the father of modern philosophy. He changed centuries of thinking when he rejected Aristotle's idea that knowledge is derived from the senses, or perception. He also noted that the senses can mislead. For example, a stick can look bent when half submerged in water. So he rejected information derived from the senses as untrustworthy, and turned to science grounded in reason, observation and experiment.
His most significant works are his Discourse on Method and Meditations on First Philosophy. His Meditations are thought by many to be the most important book in modern philosophy.
"The senses deceive from time to time, and it is prudent never to trust wholly those who have deceived us even once."1
Descartes was renowned for his scepticism. His most famous quote, "I think therefore I am" (Cogito ergo sum), was arrived at by him rejecting information derived from the senses, rejecting all perceptual powers, and turning to what he believed on account of his own internal reflections. For example, a triangle has three sides.
But what if everything, even his own internal reflections, was a huge deception like a dream; or like the prisoners in Plato's cave? He argued that thinking about our own existence proves that we exist, for how could we have thoughts if we do not? This line of thought was what led him to Cogito ergo sum.
Descartes also developed the concept of dualism, or cartesian dualism, which separates the mind and the body. The mind thinks and is not located in space, whereas the body is a physical entity, existing in the world and occupying space. But Descartes, and many since, have struggled to explain how mind and body could interact in human beings if they were so utterly unrelated.
Following on from his I think therefore I am, Descartes believed that God was resident in his mind. As an effect must have at least as much reality as its cause, he claims that it could not be an invention of his mind. And as God is perfect and does not deceive, God must exist. This challenges his own scepticism; so perhaps we shouldn't after all reject information derived from the senses!
Descartes' described his position on ethics by identifying the goal of philosophy with the attainment of a wisdom that is sufficient for happiness, similar to the views of Socrates, Plato, Aristotle, Kant and others. His famous image of the 'tree of philosophy' shows its uppermost branch as "the highest and most perfect moral system, which presupposes a complete knowledge of the other sciences and is the ultimate level of wisdom."2
Recognition by Descartes that the senses can be deceived and perceptions can be altered, is the basis on which narcissists achieve their success. Despite leading often immoral and unethical lives their ability to distort the perceptions of the people around them enables them to survive, and often prosper.
For more information about the great philosophers and their views on narcissism and happiness, read Finding Happiness.
1 René Descartes
2 Preface to the Principles of Philosophy (1644)