The History of Knowledge

Rene Descartes (ca. 1620): “As soon as I had finished the course of studies which usually admits one to the ranks of the learned... I found myself saddled with so many doubts and errors that I seemed to have gained nothing in trying to educate myself unless it were to discover more and more how fully ignorant I was.... Nevertheless, I had been in one of the most celebrated schools in all of Europe where I thought there should be wise men if wise men existed anywhere on earth.”

The History of Knowledge What was the knowledge and why was it so shaky? Scholasticism: late medieval system of knowledge 1.Aristotelianism 2.The Bible and Christian theology 3.Knowledge traditions of alchemy, astrology, and magic

The History of Knowledge Aristotelianism: Rediscovery of classical Greek writing, through the Arabs Aristotle’s biology and physics –The four elements Galen’s medicine –The four humours Pliny (et al.): natural science –Blend of observation and fantasy

The History of Knowledge Christian (and Jewish) theology and the Bible Focus on God and the spiritual realm Fixed and unchanging: a conservative view Ptolemy’s astronomical system

The History of Knowledge Problems with pre-modern knowledge (science) A shaky foundation Focus on why, not how Diminished focus on observation –Observation – limited by evidence from the senses –Pre-moderns “saw” the world imbued with “qualities” (not just quantities) The spiritual Qualities of meaning and purpose

The History of Knowledge Cracks in the Scholastic Foundation Humanism –Re-discovery of Roman/Latin writers (e.g., Lucretius, in 1417) The Reformation (Luther ) The beginning of modern science –Copernicus –Kepler –Bacon –Harvey –Descartes –Galileo –Newton

The History of Knowledge Rene Descartes ( )’s search for a new foundation Step 1: The method of doubt. If you can doubt a proposition, it is not foundational. Step 2: Beliefs that depend for their justification on sense evidence (a posteriori) are subject to doubt. –It is possible to describe a situation in which you can believe that you are having an experience, but that belief is false.

The History of Knowledge Rene Descartes ( )’s search for a new foundation Step 3: Beliefs based on rational calculation (a priori) are also subject to doubt. –The possibility of the evil demon!

The History of Knowledge Rene Descartes ( )’s search for a new foundation Step 4: The only sure thing is that I am doubting. I am thinking. If I am thinking, I must exist. –Cogito ergo sum –Je pense, donc je suis –I think, therefore I exist

The History of Knowledge Step 5: Four foundations: I exist I am thinking (and my awareness of my thoughts is indubitable and foundational). God exists (the perfect cause argument) and is no deceiver. My clear and distinct beliefs must be true.

The History of Knowledge Implications of Descartes’ foundationalism: The primacy of rationalism (as opposed to empiricism) Dualism: –Body and mind –Matter and spirit

The History of Knowledge Implications of Descartes’ dualism: Not an atheistic philosophy –God and soul exist Body and matter are distinct from God, soul, and spirit – and are therefore susceptible to scientific exploration

The History of Knowledge Descartes has been called “the father not just of modern philosophy but, in important respects, of modern culture—of modern Western culture and later, through export of its ideas, of much of modern world culture.” Discourse on the Method: “the dividing line in the history of thought. Everything that came before it is old; everything that came after it is new.”