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Unformatted text preview: Organizational Information You should have gone to your respective You discussion sections last Friday. discussion The Power Point presentations from my first two The lectures are up on the course website. lectures Course Website: http://courses.umass.edu/phil100pgraham You should have downloaded and printed out the You handout for today’s lecture. handout Reading for next time: Rene Descartes’ Reading Meditations on First Philosophy - Meditation 2 Meditations Review From Last Time What is validity? What is soundness? Is every argument with a true conclusion Is valid? valid? No! Is every argument with a true conclusion Is sound? sound? No! Review From Last Time Is every argument with all true premises Is and a true conclusion valid? and No! Is every argument with all true premises Is and a true conclusion sound? and No! Review From Last Time Is every argument in MP form valid? Yes! Is every argument in MT form valid? Yes! Is every argument in MP form sound? No! Is every argument in MT form sound? No! Review From Last Time How do you PEE an argument? How PEE First, you PRESENT it in premise First, PRESENT conclusion form and say what form it is in: conclusion For example:
1. 2. 3. Blahblahblah. If blahblahblah, then blehblehbleh. Therefore, blehblehbleh. 1,2 MP It is not the case that blehblehbleh. If blahblahblah, then blehblehbleh. Therefore, it is not the case that blahblahblah. 1,2 MT Or: Or:
1. 1. 2. 3. Review From Last Time Second, you EXPLAIN the argument by Second, EXPLAIN saying why it is that the one offering the argument thinks that the premises of the argument are true. argument Last, you EVALUATE the argument by (1) Last, EVALUATE saying whether it is valid and if so, what form it is in, and (2) saying why you think the premises are true, if you think they are, or saying why you think that one or another of the premises is false, if you think one of them is. them Review Make sure you understand the concepts of Make validity and soundness. validity Make sure you can recognize and put Make arguments in Modus Ponens and Modus Tollens form. Tollens Make sure you can PEE arguments. I am going to put some ungraded am assignments up on the course website that you can do to practice these skills. you Descartes Descartes René Descartes Dates: 1596 - 1650 At the age of eleven he entered the Jesuit college At of La Flèche. of At the time, Jesuit education was fairly modern; it At emphasized “profane science” as well as theology. emphasized Jesuit education also heavily emphasized method which Jesuit method had a profound influence on Descartes. had (Another of Descartes’ most famous works is his (Another Discourse on the Method, iin Part IV of which he argues Method n for his own philosophical system/method.) for Descartes spent much of his life trying to get the Jesuits Descartes to approve of his ideas even though in his work he challenges much of the Scholastic philosophy they espoused. espoused. Descartes René Descartes (continued) He was a true polymath. He wrote works on
Philosophy Mathematics He did revolutionary work in geometry. He was the inventor of the Cartesian coordinate system. He Cartes Science Medicine In 1649 he accepted the invitation of Queen Christina of In Sweden to go to the Swedish court to instruct her in his philosophy. philosophy. He died on Feb. 11 1650 was said to be pneumonia.
Some say that the cold of Sweden (to which he was unaccustomed) Some and the need to wake up so early to give the queen lessons at 5am each morning was too much for his naturally weak constitution (he had always been rather sickly). always Others say he contracted the disease while nursing the French Others ambassador back to health from pneumonia. ambassador Descartes René Descartes (continued) Descartes is often referred to as the father of Modern Descartes (Western) Philosophy (Western) Prior to Descartes there were perhaps two major Prior philosophical eras: philosophical The era of ancient Greek philosophy dominated by such figures as Socrates, Plato, Aristotle, and dominated others others The era of Medieval philosophy Involved the synthesis of ancient Greek philosophy with Christian Involved thought. thought. the major figures of this period being St. Augustine, St. Thomas the Aquinas, and others. The methods and philosophical system Descartes The ushered in marks a break with the reigning Scholastic philosophical system of the Medieval era. philosophical (Scholasticism is the philosophical school associated with St. (Scholasticism Thomas Aquinas and those who followed him.) Thomas Descartes’ Meditations on First Philosophy Why is it called the Meditations on First Why Philosophy? Philosophy Because, as Descartes indicated in a letter, it “treats in general of all the first things to be discovered by philosophizing”. discovered In Descartes’ time, “philosophy” was a term In covering a lot more than it does today. covering For example, a lot of what we contemporarily call For “science” was referred to then as “natural philosophy”. “science” Descartes’ interests in science, philosophy, and math Descartes’ were not as disjoint and disconnected, then, as they might seem from a contemporary viewpoint. They were all branches of philosophy, ways of coming to understand the world around us. understand Much of Descartes’ philosophical work is meant to Much ground scientific investigation of the world. Descartes’ Meditations on First Philosophy Why use the Meditations as our springboard Why Meditations into philosophy? into It is the masterwork of the “father of modern It philosophy”. philosophy”. It is, according to John Cottingham, “a vividly It dramatic account of the rejection of preconceived opinions and the search for foundations of a reliable system of knowledge”. reliable It touches on and discusses in great depth a It number of core philosophical issues of central importance to each of our lives. importance It is presented in a manner reflecting what It philosophy should be, a first-personal journey should toward/search for understanding. toward/search Meditation #1 “Some years ago I was struck by how many false things Some I had believed, and by how doubtful was the structure of beliefs that I had based on them. I realized that if I wanted to establish anything in the sciences that was stable and likely to last, I needed--just once in my life-stable to demolish everything completely and start again from to the foundations. It looked like an enormous task, and I decided to wait until I was old enough to be sure that there was nothing to be gained from putting it off any longer. I have now delayed it for so long that I have no excuse for going on planning to do it rather than getting planning to work. So today I have set all my worries aside and arranged for myself a clear stretch of free time. I am here quite alone, and at last I will devote myself, sincerely and without holding back, to demolishing my opinions.” opinions.” Meditation #1 What animates the project Descartes is What engaged in in the Meditations? Meditations A desire for certainty. desire certainty Descartes recognizes that he has believed Descartes many false things in the past, and he wants to make sure not to fall into believing anything false. anything If he wants to establish anything stable and If likely to last, it must be certain, indubitable, undoubtable. undoubtable. Meditation #1 In order to achieve a firm foundation of In certain and indubitable belief he must first tear down the “doubtful structure of beliefs” that he finds himself with and build up from scratch a new one. scratch The project of the first Meditation then, is the The destructive one of tearing down the edifice of his current system of beliefs. his Meditation #1 In building up his new system of beliefs, In Descartes will make sure that no falsity enters into the structure, he will adopt the most cautious course possible. cautious He will refrain from believing not only those things He that are false, but also those things for which he can find even the slightest grounds for doubt. can This method of doubt or methodological This method skepticism is a hallmark of the Cartesian skepticism philosophical system. philosophical Meditation #1 But he can’t examine all of his beliefs But individually in order to cast doubt on it--that would take forever. would But, as he can cast (even the slightest bit of) doubt But, on a belief by casting doubt on the beliefs on which it is based, he will aim his skeptical inquiries at the basic principles upon which all of his other beliefs rest. beliefs “[O]nce the foundations of a building have been [O]nce undermined, the rest collapses of its own accord; so I will go straight for the basic principles on which all my former beliefs rested.” which Meditation #1 Most of what we believe (and most of what Most we most strongly believe) are based on our sense perception of the world--what we see, hear, smell, taste, and feel. hear, So as a means of sowing doubt in all that he So believes, the fundamental principle that Descartes straightaway attacks is the principle of the reliability of our senses. principle Meditation #1 “Whatever I have accepted until now as most Whatever true has come to me through my senses. But occasionally I have found that they have deceived me, and it is unwise to trust completely those who have deceived us even once.” once.” us, that might be enough to cast doubt on all that we believe on the basis of our senses. that Because our senses do sometimes deceive Because For how do we know that for each thing we believe For on the basis of our senses they aren’t deceiving us in that instance? in Meditation #1 But, you might think that though the senses are But, sometimes unreliable, in some cases, it seems, they never lie--cases involving perception of things close up and immediate. up “Yet although the senses sometimes deceive us about Yet objects that are very small or distant, that doesn’t apply to my belief that I am here, sitting by the fire, wearing a winter dressing-gown, holding this piece of paper in my hands, and so on. It seems quite impossible to doubt beliefs like these, which come from the senses.” which So maybe doubting our senses will only get us as far So as doubting all of our beliefs about small things and things very far away. things Meditation #1 That’s not good enough for Descartes. This leads to his famous Dreaming Argument This Dreaming In response to the claim that we can trust our In senses about things immediately around us he writes (sarcastically): he “What a brilliant piece of reasoning! As if I were What not a man who sleeps at night and often has all the same experiences while asleep as madmen do when awake…. Often in my dreams I am convinced of just such familiar events--that I am sitting by the fire in my dressing-gown--when in fact I am lying undressed in bed!” fact Meditation #1 1. The Dreaming Argument I don’t know that I am not dreaming. 2. If I don’t know that I am not dreaming, If then I don’t know that I have hands. then 3. Therefore, I don’t know that I have Therefore, hands. hands. 1,2 MP Meditation #1 What is the justification for premise 1 of What the Dreaming Argument? the Because we are often duped into thinking Because we are awake when we are dreaming, we can’t from our experience determine whether we are dreaming or not. whether “As I think about this more carefully, I As realize that there is never any reliable way of distinguishing being awake from being asleep.” asleep.” Meditation #1 What is the justification for premise 2 of the What Dreaming Argument? Dreaming As what I take myself to perceive when I am As dreaming is in no way connected up with the world, just because I seem to perceive something when I am dreaming gives me no evidence that what I take myself to perceive is true. what So just because I seem to perceive myself as So having hands, if I am dreaming this gives me no evidence that I do have hands. evidence And so, if I am dreaming, I don’t know that I have And hands. hands. ...
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