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Theories of Knowledge Knowledge is Justified-True-Belief Person, S, knows a proposition, y, iff: Y is true; S believes y; Y is justified for S. (Note:

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Presentation on theme: "Theories of Knowledge Knowledge is Justified-True-Belief Person, S, knows a proposition, y, iff: Y is true; S believes y; Y is justified for S. (Note:"— Presentation transcript:


2 Theories of Knowledge

3 Knowledge is Justified-True-Belief Person, S, knows a proposition, y, iff: Y is true; S believes y; Y is justified for S. (Note: Gettier exceptions)

4 Justified True Belief Belief (Protagorean Theory of Appearance) True Belief ( Demands of Realism ) Justified Belief ( Questions of Pragmatism ) other variations: Mere Justification Truth Alone Justified Truth without belief

5 The individual Man is the measure of all things. 1. Assuming perception is only of what is and therefore without error (seeming errors are not real error but only equipment failures), 2. to measure (i.e., to know) is to form a perception based belief & 3. hold it in memory for recall. Measuring in this way suggests that, for the question of knowledge, there may be little or no difference between a.) perception created by the encounter between the sense organ and objects on one hand and b.) perception created by remembering, or other such faculties on the other. Faced with the problem of Expertise Protagoreanism coheres best with relativism or anti-realism and supports an ontology of change or process. Instead of insisting on an ideal or objective reality, relative expertise is decided by rhetorical appeals to virtue or beauty.

6 Despite its many difficulties the Protagorean Theory of Appearances captures our basic intuition that knowledge has something to do with our need to make sense of the world in terms of the deliverances of the senses. Further, it serves to introduce us to the challenges of relativism and Proposes that rhetoric, ethics and aesthetics may be more basic (elements/concepts in judgment, action and wisdom) than knowledge.

7 If we are not willing to accept an ontology of Heraclitean Change nor accept that Rhetoric ought to settle arguments about expertise, how will introducing a concept of Truth help to define knowledge? While the meaning of the term true is not settled, we will briefly explore an intuitive notion of correspondence. For many of us there is an unreflective confidence that there is an objective world that exists independent of anyones beliefs. ( Demands of Realism ) Truth, then, will be that relation which obtains between some x and the world. ( candidates for x may be sentences, propositions, facts, thoughts, expressions, function, etc.) One characterization of this relation is Correspondence. And the relevant belief will be a judgment that correspondence obtains.

8 What is false fails to be true because falsehoods fail to correspond with the world, e.g., The present King of the U.S.A. is bald. is false because there is no king, Not because of anyone's belief, Not because of anyones ability to convince anyone. Not because its morally praiseworthy or pretty.

9 Supposing we are undecided about realism or reject the very idea of correspondence, we may be attracted to the following: The true is the name of whatever proves itself to be good in the way of belief, and good, too, for definite assignable reasons. (W. James 1907: 42) The true, to put it very briefly, is only the expedient in the way of our thinking, just as the right is only the expedient in the way of our behaving. Expedient in almost any fashion; and expedient in the long run and on the whole, of course. (1907: 106) A Coherence Theory of Knowledge: Ideas … become true just in so far as they help us to get into satisfactory relations with other parts of our experience. (1907: 34)

10 Justified beliefs seem to depend upon a confidence in a prior knowledge to underwrite new knowledge. This begs the question, how do we know the prior knowledge is really knowledge?

11 To test whether a proposed analysis is correct, ask both (a) Is every possible case in which S knows that p a case in which each of these conditions is met. –- Is each and every condition necessary. and (b) Is every possible case in which all the conditions are met a case in which S knows that p, -- Are the conditions jointly sufficient?

12 While some have argued that the three conditions for knowledge were not all necessary, For more than 2000 years these three conditions on knowledge, i.e., justified, true, belief, were thought to be jointly sufficient to constitute knowledge. In 1963, owing to a journal article by Edmund Gettier, we found out that the three conditions were not enough to cover all possible cases.

13 It turns out that we can sometimes be in a position to know or fail to know something for reasons unrelated to whether we believe it, we have justifications for our belief, and in fact our belief is borne out by the facts. Sometimes knowledge can be a matter of luck in addition to justified true belief!

14 Example: Imagine youre in a field and you evidently see a row of hay bales and claim: I know that there is a hay bale in the field. You have this belief You justify the belief on the grounds of your empirical investigation, i.e., you see it. In fact, there is a bale of hay in the field. But Turns out youre just lucky. An artist has put extremely realistic 3D renderings of hay through out the field (Its extremely good evidence although completely bogus) and behind just one of them (not in your direct field of vision) there is indeed a bale of hay.

15 Reliabilism: what stands in the way of epistemic luck what turns a true belief into knowledge is the reliability of the cognitive process that produced the belief Varieties of Reliabilism (Internal or External) Justification Reliabilism (internal or External) Knowledge Reliabilism

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