Intro to Philosophy Phil 110 Lecture 12: 2-15 Daniel Kelly I. Mechanics A. Upcoming Readings 1. Today we ll discuss a. Descartes, Meditations on First Philosophy (full.pdf) 2. Next week a. Locke, An Essay Concerning Human Understanding b. Berkeley, Three Dialogues Between Hylas and Philonus B. Down the road a bit: 1. Midterm Exam: in class, Thursday 3/1 2. Final Exam has been scheduled a. Wednesday 05/02 b. 3:30p - 5:30pm c. This Room: Wetherill 172 d. Cumulative New Chapter: Epistemology: The Theory and Nature of Knowledge I. Some Preliminaries II. Descartes (1596-1650) A. Some Background B. Descartes Epistemological Project C. Wiping the Slate Clean: D. The Cogito E. Extending the Domain of Certainty 1. Descartes thinks he can do better than one belief in the foundation a. He wants to include not just the Cogito b. But all of the contents of consciousness 2. He argues that when he has any conscious thought a. What he thinks may be entirely mistaken or false i. The content of the belief, what it asserts, is doubtable, can be correct or mistaken ii. The Cogito excepted, of course b. But he cannot be mistaken i. That he is thinking it ii. Or that he is having that thought itself c. Some example thoughts: i. Reno NV is west of Los Angeles CA A. When I consciously think Reno NV is west of Los Angeles CA 1. The thought might be true or false 2. (Hint, it s true) B. But as the thought runs through my mind 1. I can be certain that I am thinking it 2. I am thinking that Reno NV is west of Los Angeles CA is beyond even
the power of an Evil Demon to make me doubt ii. 5 + 7 =12 A. When you consciously think 5 + 7 =12 1. You can t be absolutely certain that what the thought asserts is correct 2. Remember, Descartes thinks the possibility of an Evil Genius casts doubt on even mathematical beliefs B. But as the thought runs through your mind 1. You can be certain that you are thinking it 2. I am thinking 5 + 7 =12 is beyond even the power of an Evil Demon to make me doubt iii. There is a table in front of me A. When you consciously have this sensory experience and perceptual belief 1. The perception itself a. Might correctly represent your surrounding environment b. Or it might be mistaken 2. In this case a. There might be a table b. It might be an illusion or hallucination c. You could be dreaming B. But as you are having that sensory experience and perceptual belief 1. You can be certain a. That you are having it b. That you believe it 2. I am having the experience of there being a table in front of me is beyond the power of even an Evil Demon to make you doubt 3. From this last example, we can separate out two importantly different meanings of perceive a. The distinction applies to other more specific perception verbs as well i. See ii. Hear etc. b. The phenomenological sense i. If someone perceives a table in this sense, then ii. There is a table-like perception in the contents of her visual consciousness (let s say she sees it)
A. However, there may or may not be an actual table in the world, corresponding to that perception B. In technical terms 1. The perception or perceptual experience may or may not be veridical 2. Sentences can be true or false 3. Analogously, perceptual experiences can be veridical or illusory c. The veridical sense i. If someone perceives a table in this sense, then A. There is a table-like perception in the contents of her visual consciousness, (i.e. she has a phenomenological perception of the table) B. AND there is an actual table in the world where she perceives it ii. In cases of veridical perception A. A person s subjective, 1 st person experience of the world accurately (veridically) B. Depicts or represents the 3 rd person accessible, objective world as it really is iii. Note that many of the cases we have been considering so far involve perceptual experiences that are merely phenomenological, but not veridical A. Descartes 3 arguments use these 1. Illusions and hallucinations 2. Dreams 3. Massive deception by Evil Demons B. While inside the Matrix, Neo, Trinity and everyone else are having perceptions that are only phenomenological, but not veridical F. Descartes Archimedean Point 1. This is metaphorical, of course a. An Archimedean point is one that is fixed and unmoving i. Archimedes (of eureka! fame) was the first to discover and explain the principle of the lever ii. Claimed that armed only with a lever and a single unmovable point, he could move the entire world b. In the context of his epistemological project, Descartes single unmovable (un-doubtable) point is the Cogito 2. From single belief expressed by the Cogito a. He extends the domain of certainty to include the entire contents of consciousness b. All which he wants to serve as the indubitable bedrock foundation of the rest of his beliefs i. The bottom tip of inverted pyramid ii. The epistemic gold that can support the rest
G. The Medieval Argument: Descartes Bridge from consciousness to the external world 1. To extend justification outward from the foundational beliefs about the contents of consciousness, Descartes firsts asserts a principle 2. Medieval Principle: there must be at least as much reality in an (efficient) cause as there is in the effect it produces a. This principle is drawn from a piece of Medieval philosophy called the doctrine of degrees of reality b. Descartes provides some support for the principle i. It is a clear and distinct idea A. If you reflect on it B. You will see that such ideas are obvious by the natural light ii. Descartes holds clear and distinct ideas, including this Medieval Principle, are straightforwardly true 3. With this principle in hand, Descartes goes on to offer an argument for God s existence a. Premise 1: The Medieval Principle tells us there must be at least as much reality in an (efficient) cause as there is in the effect it produces b. Premise 2: The idea of God is very great, and so has a very high degree of reality c. Premise 3: Whatever caused the idea of God (the effect mentioned in the second premise) must have had as much or more reality than that idea d. Conclusion: The cause of the idea of God must have been: God himself! 4. Finally, Descartes uses God for his bridge to the External World a. If even our clear and distinct ideas could deceive us, there would be no way to correct the error b. This would imply that God is a deceiver c. But God is good, and so is not a deceiver d. Therefore the clear and distinct contents of our consciousness must be trustworthy i. Our clear and distinct ideas must be true ii. Our clear and distinct perceptions must be veridical 5. Schematically, the line of argument can represented like this: Medieval Principle Idea of God God himself clear & distinct ideas must be veridical H. Skeptical Objection: Circularity 1. An argument or line of reasoning is circular when it assumes what it is trying to prove a. The conclusion the argument wishes to establish i. Appears as a premise in the argument itself ii. Or is used to support one of those premises b. In other words, circular lines of reasoning beg the question
2. In the case of the Medieval argument, the problematic claim is that clear and distinct ideas must be true or veridical a. This is Descartes conclusion i. It is the justificatory bridge between the contents of our consciousness and the external world itself ii. It is how we can tell when our phenomenological perceptions are in fact veridical they are clear and distinct b. The problem is that Descartes cites this as his reason for accepting the first premise, namely the Medieval Principle c. Once we point this out, we can see that Descartes gives us no legitimate or convincing reason to accept that principle i. So the first premise (which sounds very odd anyway) is left unsupported ii. If we reject the first premise, then the entire argument fails Medieval Principle Idea of God God himself clear & distinct ideas must be veridical clear & distinct ideas must be veridical I. Descartes Legacy 1. Descartes has influenced centuries of philosophy with his focus on the inner, mental, the 1 st person, subjective point of view a. As a starting place for epistemology b. As an understanding of what minds and persons are 2. Dualism a. What is sometimes called Cartesian dualism is a doctrine in the philosophy of mind i. Solution to the mind body problem ii. We ll talk about in more detail in a later chapter b. It maintains that the essence of persons, as opposed to mere animals, is that we are thinking substances c. As thinking conscious beings, we are connected to, but importantly distinct from, our physical bodies 3. Solipsism: a. A Latin term that means myself, alone b. As an insult, to call someone solipsistic is to accuse them of being extremely egoistic, self-involved, self-absorbed, selfindulgent or overly preoccupied with themselves c. As a philosophical position, solipsism is i. The theory (or usually the worry) that your own self, your own mind, the contents of your consciousness is A. The only thing that that can truly be known B. Perhaps all that actually exists
ii. Descartes epistemological project and privileging of the 1 st person point of view raises the question of how we can ever get outside our own consciousness 4. The problem of perception a. How can we penetrate what s become called the veil of perception? i. Tell which of our perceptions is veridical ii. Gain knowledge of the external world A. Descartes way of framing the issues here was widely accepted B. But his solution (what we re calling the Medieval argument) convinced no one C. So the issue was left unresolved b. On the one hand, we have a plausible Cartesian picture i. We never perceive the world directly, in a way that is not mediated by our own doubtable senses ii. The only thing that we directly perceive are our own 1 st person perceptual experiences (sense data) iii. The issues of whether, when, and how those experiences and sense data accurately depict the external world are revealed to be very problematic iv. The Cartesian picture can leave us feeling trapped inside our own minds c. On the other hand, we have basic common sense i. Most people believe that their perceptions resemble or correctly represent the external world ii. That their perceptions get it right most of the time A. In something like the way the pictures on a TV screen can resemble or correctly represent whatever scene the TV cameras are recording B. This is often called the representational theory of perception d. The Problem: i. How can the common sense beliefs about perceptions and their relation to reality be justified? A. When, if ever, do we have good reason to think that those perceptions are right or wrong, veridical or illusory B. Especially given that we can never 1. Step outside of our perceptions or simply bypass the veil of perception 2. And compare those perceptions to the reality of the external world? ii. How to justify beliefs about the external world given A. That we can t perceive the world directly B. But only mediated through our uncertain, doubtable and fallible perceptions