WHERE ARE WE KNOW NOW?

Transcription

1 WHERE ARE WE KNOW NOW? A review of what we have covered in theory of knowledge so far IT ALL STARTS WITH DESCARTES Descartes Project (in the Meditations): To build a system of knowledge. I. A Foundational Theory of Knowledge attempts to build a theory such that : a. Each of the initial premises must be indubitable (no one could doubt it) and incorrigible (not subject to correction). In other words, each premise must be such that were any person any minimally rational and sane person to consider that proposition, he or she would agree that the premise is true. b. Each step of the argument must follow indubitably from the previous premise(s). In Descartes terms, we can simply see by The Light of Reason, that each step must be true given the previous step(s). 1

2 II. Using the method of doubt (discarding every belief that is not certain), he arrives at the Cogito I think, therefore I am and the conclusion that the only things of which he is certain are the contents of his own thoughts the way things seem to him. He concludes that he knows the contents of his mind better than anything else and this includes innate ideas. And now I have brought myself back to where I wanted to be. I now know that physical objects are not really known through sensation or imagination but are grasped by the understanding alone. And from the fact that physical ideas are grasped in virtue of their being understandable (rather than tangible or visible) I infer that I can t know anything more easily and plainly than my mind. p III. Starting with the idea of God, and using only premises that Descartes sees clearly and distinctly to be true, Descartes proves the existence of God. Having proved the existence of God, he says: The whole argument comes down to this: I know that I could not exist with the my present nature (that is, that I could not exist with the idea of God in me) unless there really were a God the very God of whom I have an idea, the thing having all of the perfections that I can t fully comprehend but an somehow reach with thought, the thing that clearly cannot be defective. From this it is obvious that he can t deceive, for the natural light reveals that fraud and deception arise from defect. (p. 123) Hence, because God is no deceiver, the truth of those things I believe to be true is assured. SKEPTICISM IS FALSE. 2

3 For Descartes Knowledge = Justified, True, Belief Justification is NONdefeasible (i.e. our reasons guarantee truth) When we have knowledge, we know that we have knowledge. We can prove that skepticism is false. For Locke.. As an Empiricist, Locke starts with the view that all of our Ideas either come from the senses or they are derived from sensory ideas even the concepts of numbers, of God, or abstract concepts like government, etc. Following Descartes, he starts with the view that we have access to only the content of our ideas thus we have only Certain Knowledge of sensory ideas and of what Locke called relations between Ideas. You also have knowledge of mathematical truths and of the existence of God. 3

4 What about knowledge of the external world? Locke: We can be reasonably certain that there is an external world for two reasons: (a) our perceptions are forced upon us (they occur involuntarily) we can t control the information that comes to us through our senses (b) There is a definite pattern to our perceptions of the external world. Therefore something must be causing theses perceptions and the simplest hypothesis is that there is an external world. But what does this mean for Locke s theory of knowledge? Appiah s Interpretation Knowledge = Justified True Belief But justification need not be certain; our reasons are defeasible. Consequence: we can have justified, true beliefs that no one would want to call them knowledge. 4

5 But what does this mean for Locke s theory of knowledge? Appiah s Interpretation Knowledge = Justified True Belief But justification need not be certain; our reasons are defeasible. Consequence: we can have justified, true beliefs that no one would want to call them knowledge. A Better Locke/Interpretation Knowledge = Justified True Belief We can have Certain Knowledge about only our Ideas and the relations between them. All other knowledge is only probable knowledge : we can know what is probably true. For Descartes Knowledge = Justified, True, Belief Justification is NONdefeasible (i.e. our reasons guarantee truth) When we have knowledge, we know that we have knowledge. We can prove that skepticism is false. For Locke Knowledge = Justified True Belief Our reasons must be NONdefeasible. All Ideas come from the senses. When we have knowledge, we know that we have knowledge We cannot prove that Skepticism is false. We can know are facts about our Ideas (which come from the senses) and the relations between them. Hence, we cannot have real knowledge about the physical world, only probable knowledge. 5

6 Verificationism Skepticism is meaningless! So we don t have to address it. Verificationism Skepticism is meaningless! So we don t have to address it. 1. According to the Logical Positivists, in order for a sentence to have meaning there must be a rule for using that sentence a rule that tells us when we are using the sentence correctly and when we are not using the sentence correctly. 6

7 Verificationism Skepticism is meaningless! So we don t have to address it. 1. According to the Logical Positivists, in order for a sentence to have meaning there must be a rule for using that sentence a rule that tells us when we are using the sentence correctly and when we are not using the sentence correctly. 2. If there were no such rule, we would have no idea how to use the sentence. And hence it would not be a meaningful sentence. Verificationism Skepticism is meaningless! So we don t have to address it. 1. According to the Logical Positivists, in order for a sentence to have meaning there must be a rule for using that sentence a rule that tells us when we are using the sentence correctly and when we are not using the sentence correctly. 2. If there were no such rule, we would have no idea how to use the sentence. And hence it would not be a meaningful sentence. NOTE: the logical positivist does not claim that you, yourself, must be capable of finding out whether any sentence is true or false. Rather, for a sentence to be meaningful, you must be able to conceive of circumstances that would show whether the sentence was true or false. 7

8 Take sentences about history. John Locke was born at Wrington, a village in Somerset, on August 29, What makes it true? Obviously you cannot go back in time, say to August 28, 1632, to the village of Wrington in Somerset, England, and wait to see whether, the next day, John Locke is born. But we do know exactly what would make that sentence true, namely, whether or not, on that day in history, John Locke was or was not born. So the sentence is meaningful (on the Verificationist Theory of Meaning) 8

9 What about sentences that posit skepticism? 1. There is no physical world beyond you: rather you are a brain in a vat controlled by the Evil Scientist, Mary. What about sentences that posit skepticism? 1. There is no physical world beyond you: rather you are a brain in a vat controlled by the Evil Scientist, Mary. What makes this true is if there is scientist Mary, who is currently feeding your brain electrical impulses while floating your brain in a vat of cerebral spinal fluid. Of course, there is no way for YOU to know whether this is true, to somehow check out the hypothesis. But you can well imagine what would have to be the case in order for the sentence to be true. 9

10 2) You may think that you are awake and that there is a physical world beyond you; in fact, right now you are fast asleep dreaming and everything you see before you at present does not exist. 2) You may think that you are awake and that there is a physical world beyond you; in fact, right now you are fast asleep dreaming and everything you see before you at present does not exist. Of course, as in the case of Evil Scientist Mary, there is no way for you to check the truth or falsity of this sentence, because even if you seem to wake up right now, you may still be asleep. But do you know what would make it true? Yes: If your body lies asleep in bed, twitching and moaning, and muttering I m dreaming! Maybe I m dreaming!, and then eventually you wake up and report the strangest dream, etc. then this would make the statement true. 10

11 3. Although you may think you are awake, in fact you have never been awake. You have always been asleep, merely dreaming about a physical world that does not exist, occasionally dreaming that you wake up. 3. Although you may think you are awake, in fact you have never been awake. You have always been asleep, merely dreaming about a physical world that does not exist, occasionally dreaming that you wake up. This is trickier. If there really is no physical world beyond you, what exactly would make this sentence true? We can t imagine you sleeping in bed, because if this sentence is true, then there is no physical you and no physical bed. 11

12 So has Verificationism shown that skeptical worries are meaningless? NO. It is not clear whether (3) is meaningful or not that we can talk sensibly about what it would means to say that we are dreaming ALL THE TIME. But certainly (1) and (2) seem to be meaningful, even on the Verificationist theory of meaning. And we can use either (1) or (2) in order to explain skepticism about the physical world. So it does not seem like the Skeptical Thesis is meaningless. Causal Theories of Knowledge Forget REASONS. Justification is about your causal connections to the world not about what you may know about it! 12

13 Thus far there have been two very large problems with any theory of knowledge. 1) Skepticism About the External World So far, for everyone, including the Logical Positivists: Knowledge = Justified, True Belief. Thus far there have been two very large problems with any theory of knowledge. 1) Skepticism About the External World So far, for everyone, including the Logical Positivists: Knowledge = Justified, True Belief. Justification is understood in terms of having good reasons to believe that something is true. For Descartes (and probably for Locke too), your reasons must guarantee the truth of the proposition, be indefeasible. 13

14 Thus far there have been two very large problems with any theory of knowledge. 1) Skepticism About the External World So far, for everyone, including the Logical Positivists: Knowledge = Justified, True Belief. Justification is understood in terms of having good reasons to believe that something is true. For Descartes (and probably for Locke too), your reasons must guarantee the truth of the proposition, be indefeasible. But you can never have this kind of justification for propositions about the nature of the external world. Thus far there have been two very large problems with any theory of knowledge. 1) Skepticism About the External World So far, for everyone, including the Logical Positivists: Knowledge = Justified, True Belief. Justification is understood in terms of having good reasons to believe that something is true. For Descartes (and probably for Locke too), your reasons must guarantee the truth of the proposition, be indefeasible. But you can never have this kind of justification for propositions about the nature of the external world. So, SKEPTICISM RULES. 14

15 Thus far there have been two very large problems with any theory of knowledge. 1) Skepticism About the External World So far, for everyone, including the Logical Positivists: Knowledge = Justified, True Belief. Justification is understood in terms of having good reasons to believe that something is true. For Descartes (and probably for Locke too), your reasons must guarantee the truth of the proposition, be indefeasible. But you can never have this kind of justification for propositions about the nature of the external world. So, SKEPTICISM RULES. 2) Gettier Problems a) You have good reasons for believing that p is true. b) The statement p is true. c) But your belief is correct only through blind, dumb, luck. So we don t want to say that you KNOW that p is true as the truth of what you believe depends on sheer good luck. Example. Knowing that your Blue Honda Fit is in its parking spot. 15

16 2) Gettier Problems a) You have good reasons for believing that p is true. b) The statement p is true. c) But your belief is correct only through blind, dumb, luck. So we don t want to say that A KNOWS that p is true. Example. Knowing that your blue Honda Fit is in its parking spot. You leave your blue Honda Fit in parking spot #347 and walk away. 2) Gettier Problems a) You have good reasons for believing that p is true. b) The statement p is true. c) But your belief is correct only through blind, dumb, luck. So we don t want to say that A KNOWS that p is true. Example. Knowing that your blue Honda Fit is in its parking spot. You leave your blue Honda Fit in parking spot #347 and walk away. You walk by the parking structure at noon, and see a blue Honda Fit in #

17 2) Gettier Problems a) You have good reasons for believing that p is true. b) The statement p is true. c) But your belief is correct only through blind, dumb, luck. So we don t want to say that A KNOWS that p is true. Example. Knowing that your blue Honda Fit is in its parking spot at 5 p.m.. You leave your blue Honda Fit in parking spot #347 and walk away. You walk by the parking structure at noon, and see a blue Honda Fit in #347. At 5:00 p.m. when you leave work, you know that your blue Honda Fit is in its spot and you walk to your car secure in your knowledge (produced by in your superior epistemic system/powers). However 9:05 a.m. A thief disguised as an SFU security guard, hotwires your car. She drives your Fit to the nearest Bank of Montreal, parks it in a NO PARKING zone, and goes in to rob the bank. She leaves the car running outside a 9:32. 17

18 However 9:05 a.m. A thief disguised as an SFU security guard, hotwires your car. She drives your Fit to the nearest Bank of Montreal, parks it in a NO PARKING zone, and goes in to rob the bank. She leaves the car running outside a 9:32. 9:32 a.m. A passing SFU business student sees an idling Blue Fit. He is desperate to get to city hall to purchase a Small Business License before they close for lunch. He hops in and drives away. However 9:05 a.m. A thief disguised as an SFU security guard, hotwires your car. She drives your Fit to the nearest Bank of Montreal, parks it in a NO PARKING zone, and goes in to rob the bank. She leaves the car running outside a 9:32. 9:32 a.m. A passing SFU business student sees an idling Blue Fit. He is desperate to get to city hall to purchase a Small Business License before they close for lunch. He hops in and drives away. 11:25 a.m. Meanwhile, back at SFU, a desperate PHIL 100 student, running late for his tutorial at 11:30 a.m. is cruising the parking structure, looking for an empty spot. He spys an empty spot and leaves the car there. That spot is #

19 However 9:05 a.m. A thief disguised as an SFU security guard, hotwires your car. She drives your Fit to the nearest Bank of Montreal, parks it in a NO PARKING zone, and goes in to rob the bank. She leaves the car running outside a 9:32. 9:32 a.m. A passing SFU business student sees an idling Blue Fit. He is desperate to get to city hall to purchase a Small Business License before they close for lunch. He hops in and drives away. 11:25 a.m. Meanwhile, back at SFU, a desperate PHIL 100 student, running late for his tutorial at 11:30 a.m. is cruising the parking structure, looking for an empty spot. He spys an empty spot and leaves the car there. That spot is # :00 NOON. You walk by and see a blue Honda fit in #347. However 9:05 a.m. A thief disguised as an SFU security guard, hotwires your car. She drives your Fit to the nearest Bank of Montreal, parks it in a NO PARKING zone, and goes in to rob the bank. She leaves the car running outside a 9:32. 9:32 a.m. A passing SFU business student sees an idling Blue Fit. He is desperate to get to city hall to purchase a Small Business License before they close for lunch. He hops in and drives away. 11:25 a.m. Meanwhile, back at SFU, a desperate PHIL 100 student, running late for his tutorial at 11:30 a.m. is cruising the parking structure, looking for an empty spot. He spys an empty spot and leaves the car there. That spot is # :00 NOON. You walk by and see a blue Honda fit in # :30 p.m. The PHIL 100 student leaves his tutorial and drives away in his blue Honda fit. 19

20 However 9:05 a.m. A thief disguised as an SFU security guard, hotwires your car. She drives your Fit to the nearest Bank of Montreal, parks it in a NO PARKING zone, and goes in to rob the bank. She leaves the car running outside a 9:32. 9:32 a.m. A passing SFU business student sees an idling Blue Fit. He is desperate to get to city hall to purchase a Small Business License before they close for lunch. He hops in and drives away. 11:25 a.m. Meanwhile, back at SFU, a desperate PHIL 100 student, running late for his tutorial at 11:30 a.m. is cruising the parking structure, looking for an empty spot. He spys an empty spot and leaves the car there. That spot is # :00 NOON. You walk by and see a blue Honda fit in # :30 p.m. The PHIL 100 student leaves his tutorial and drives away in his blue Honda fit. 4:25 p.m. The SFU business student arrives at SFU for his 4:30 class, and drives desperately around the parking structure. He finds an empty spot. #347. He parks the car and leaves. However 9:05 a.m. A thief disguised as an SFU security guard, hotwires your car. She drives your Fit to the nearest Bank of Montreal, parks it in a NO PARKING zone, and goes in to rob the bank. She leaves the car running outside a 9:32. 9:32 a.m. A passing SFU business student sees an idling Blue Fit. He is desperate to get to city hall to purchase a Small Business License before they close for lunch. He hops in and drives away. 11:25 a.m. Meanwhile, back at SFU, a desperate PHIL 100 student, running late for his tutorial at 11:30 a.m. is cruising the parking structure, looking for an empty spot. He spys an empty spot and leaves the car there. That spot is # :00 NOON. You walk by and see a blue Honda fit in # :30 p.m. The PHIL 100 student leaves his tutorial and drives away in his blue Honda fit. 4:25 p.m. The SFU business student arrives at SFU for his 4:30 class, and drives desperately around the parking structure. He finds an empty spot. #347. He parks the car and leaves. 5:00 p.m. You walk to your car secure in the knowledge that your blue Fit is in #

21 Normally leaving your car in the parking lot and seeing a car of the same description in that exact spot 3 hours later, is good evidence that your car is where you left it. Normally, you infer that a car that looks exactly like your car and is parked in the same place IS your car. But here, the inferences is incorrect. Hence you do no know that your car is in your parking spot. In light of this kind of problem (what I ll call the dumb luck problem) and the general worry of skepticism Some philosophers have wondered whether justification is NOT just a matter of what reasons a person has or what a person knows, but how your beliefs connect to the world. 21

22 On a causal account of knowledge: a. You must believe that S b. S must be true c. Your belief in S must be caused in the appropriate way. In the case of the Blue Fit, your belief that your car was in the parking lot was caused by you seeing a Blue Honda Fit. Normally, this would be enough to justify your belief that your car was sitting in its parking place. But THAT Honda Fit was not YOUR Honda fit. But your belief was not caused in the right kind of way. Thus on the causal account you do NOT know that your car is in the parking garage. Things to NOTE about Causal Accounts. 1. Causal accounts called externalist accounts of knowledge because whether or not a belief counts as knowledge depends upon the way the world is (its causal relation to your belief) NOT upon your reasons for believing what you do. That is, it depends upon events that are EXTERNAL to you. 22

23 Things to NOTE about Causal Accounts 1. Causal accounts called externalist accounts of knowledge because whether or not a belief counts as knowledge depends upon the way the world is (its causal relation to your belief) NOT upon your reasons for believing what you do. That is, it depends upon events that are EXTERNAL to you. 2. Because knowledge depends upon facts that are external to you, you may not know when you have knowledge and when you do not. You do NOT know that know (or don t know) in all cases. 3. There is no such thing as a foundational causal account of knowledge, because justification (on this account) does not depend upon what you know. Thus we do not need Cartesian indubitable axioms from which to reason. 23