LectureonJTB Final

8/3/2019 LectureonJTB Final

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The Senses of Knowing

1. There are different senses of knowledge or different kinds ofknowledge. Among the three most significant are 1) propositionalknowledge, 2) acquaintance knowledge, and 3) how to knowledge .

2. Propositional knowledge is knowledge of facts or true propositions .

a. A sentence is an expression of a belief in a proposition.b. We may think of belief as a relation between subject and a

proposition.

i. If the proposition one believes is true, then ones beliefis true and if the proposition one believes is false, thenones belief is false.

c. We may also think of propositional knowledge as a relationbetween a subject and a proposition . Propositional knowledge is arelation between a subject and a true proposition .

3. To say that a person has acquaintance knowledge of someone is to implythat he/she is acquainted with him/her or that he/she has met him/her.

a.

One can have a great deal of propositional knowledge aboutsomeone without having acquaintance knowledge of him/her.

b. One can have acquaintance knowledge of things other than people(e.g. acquaintance knowledge of Paris or the taste of a mango).

c. One may have propositional knowledge without having the sort ofacquaintance knowledge.

4. There is one sense of knowing how to x which implies that one h as theability to X and another sense that doesnt (this sense is simply a

matter of having a propositional knowledge about how to do it ).

5. Traditionally, philosophers have been most concerned with propositionalknowledge. They want to know what is true and they want to evaluate andassess their own claims, and those of others, to know the truth. Whenthey ask about the extent of our knowledge, they are typicallyconcerned with the extent of our propositional knowledge, with theextent of the truths we know.

Knowledge as having an Epistemically Justified True Belief

1. What is it for a subject, S, to know that p (where p is someproposition)? [What is knowledge?]

2. D1: S knows that p = Df. S believes that p. a. Believing something is sufficient for knowing it.b. If D1 is true then someone who believed a false proposition would

know it.

c.

Mere belief is not sufficient for knowledge.d. Knowledge requires that ones belief is true.3. D2: S knows that p = Df. (1) S believes that p and (2) p is true.

a. One knows that p if and only if one has a true belief that p.b. Having a true belief that p is sufficient for ones knowing that

p.

c. One might have a true belief that is not knowledge.


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d. True beliefs that are merely lucky guesses or mere hunches orbase on wild superstitions are not instances of knowledge.

4. JTB: S knows that p = Df. (1) S believes that p, (2) p is true, and (3) p is epistemically justified for S .

a. Knowledge requires epistemically justified true belief .Dispositional beliefs and Occurrent beliefs

1. When we consider a proposition there are three different attitudes wecan take toward it. 1) We can believe it or accept it as true, 2) wecan believe that it is false or believe its negation, 3) we canwithhold belief in it or suspend judgment.

2. Believing a proposition needs to be distinguished from otherpropositional attitudes such as entertaining and considering aproposition. To entertain a proposition is merely to hold it beforethe mind. To consider a proposition is to entertain it and to study orexamine it.

a. One can entertain a proposition without believing it.

b.

One can believe something without entertaining or considering it.3. Dispositional beliefs are that we are not entertaining or considering.

Occurrent beliefs are beliefs that we are entertaining.

4. Having dispositional beliefs is not the same as having a disposition tobelieve something. A person may have a disposition to believe in aproposition even if he/she did not have a dispositional belief in it.

5. Knowledge requires either occurrent or dispositional belief, beliefranges in intensity or strength from complete and firm conviction totentative and cautious acceptance.

6. JTB: knowledge simply requires justified true belief. As long as onebelieves that p and the other conditions are met, then one knows that pwh atever the intensity of ones belief .

Theories of Truth

1. The Correspondence Theory of Truth (CTT): 1) a proposition is true ifand only if it corresponds to the facts, 2) a proposition is false ifand only if it fails to correspond to the facts, 3) the truth of aproposition or belief is dependent on the facts or upon the way theworld is.

a. It is not because we think truly that you are pale, that you are pale: but because you are pale we who say this have truth.Aristotle

b. A proposition is not true because of what we believe about it.The truth of the proposition does not depend on believing it oron what we believe about it.

2. CTT: one and the same proposition cannot be both true and false.Neither can it be true for you and false for me. Truth is notrelative in this way.

a. The truth of the proposition is determined by the facts and notby whether you or I believe it, two persons might thus disagreeabout the truth of some proposition.

b. Objection 1 : The floating earth disk


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c. Objection 2 : Tom says, Jim says d. Objection 3 : Some object that unless we have some explanation of

what it is for a proposition to correspond with the facts , thetheory is not very informative.

e. Others object that the theory is uninformative because the notionof a fact is without making use of the concepts of truth andfalsity, and, therefore, the correspondence theory is circularand ultimately unenlightening.

3. The Pragmatic Theory of Trutha. True beliefs are generally useful and false beliefs are not.b. A proposition is true if and only if believing it or acting on it

is, or would, be, useful or expedient.

c. The true is only the expedient in the way of our behaving,expedient in almost any fashion, and expedient in the long runand on the whole course. William James

d. Objection 1: suppose that true beliefs generally provide a goodbasis for action, that they are generally useful and that false

beliefs are generally a bad basis for action. Even if this is so,it would not follow that we should identify true belief withuseful belief. Sometimes a true belief might have a very bad consequences and a false belief might have very good ones . Whatis useful to believe is not always true and what is true is notalways useful to believe.

4. The Coherence Theory of Trutha. The fact that a proposition coheres or hangs together with

other propositions one believes [is] indicative of its truth or agood reason to believe its true.

b. Proponents of the coherence theory of truth treat coherence notmerely as a source of justification; they take coherence to be acondition of truth.

c. For a proposition to be true is nothing more than a matter of itscoherence with other propositions.

d. Assume coherence as the test [of truth] and you will be drivenby the incoherence of your alternatives to the conclusion that itis al so the nature of truth. Brand Blanshard

e. Objection 1 : The concept of coherence is murky. The concept ofcoherence is at least as much in need of explanation as those ofcorrespondence and fact.

f. Objection 2 : we cannot say simply that a proposition is true ifand only if it belongs to a coherent set of propositions.

i. A very realistic piece of fiction might be a coherent setof false propositions. (Descartes dream reality)

g. Objection 3 : we should not confuse a criterion of justificationwith a condition of truth and we should not assume that becausewe have a criterion of justification we have ipso facto acondition of truth.


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Epistemic Justification

1. Unlike practical or moral (prudential) justification epistemicjustification seems to be tied in an important way to truth.

2. A proposition can be true and not justified.a. e.g. the number of stars are even

3. A proposition can be justified and not true. One can be justified inbelieving a proposition that is false.

a. e.g. Lisas twin 4. We need to distinguish a propos itions being justified for a person

from justifying it . Justifying a proposition is an activity that oneengages in often when ones belief has been challenge. A propositionsbeing justified for a person is a state that one is in. Knowledge that

p requires that one be justified in believing that p. There are a great many things that each of us knows that we have never attempted to

justify .

5. Unlike truth, justification is relative in the sense that a propositioncan be justified for one person, but not for another. A proposition canbe justified for a person at one time, but not at another time.

6. Epistemic justification comes in degrees. It ranges from propositionsthat are certain or maximally justified for us to propositions that arejust barely justified, that are just barely reasonable to accept. JTBwould say that while knowledge does not require certainty, it doesrequire a high degree of justification.

7. A proposition can be epistemically justified for a person even if hedoes not believe it. e.g. pessimistic Malcomb, the confident Batter.

8. Some philosophers draw a distinction between a propositions beingjustified for a person and a propositions being well - founded for aperson.

a. If a proposition is well-founded for a person, then he not onlyhas good reasons for believing it, he also believes it on thebasis of good reasons. In such a case, we may also say that hisbelief that p is well-founded or that he justifiably believesthat p .

b. Knowledge requires not simply that one have evidence for onesbeli ef, but that ones belief be based on ones evidence.

c. JTB: S Knows that p =Df. (1) S believes that p, (2) p is true,and (3) Ss belief that p is well -founded.

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LectureonJTB Final