Epistemology (How do you know something?)

1. Epistemology(How do you know something?) How do you know your science textbook is true? How about your history textbook? How about what your parents tell you? How about your doctor? Is there a way to verify what they say is true? What does it mean to be true? Are there things that are absolutely true? Why is knowledge important? How does knowledge give you power? Are our senses always reliable?

2. Sources • http://www.galilean-library.org/philosophy.html • Microsoft Encarta Encyclopedia 2003 • Introduction to Philosophy, by Peter McInerney, Harpercollins College Outline

3. Knowledge • Plato’s definition of knowledge (from Theaetetus): “knowledge is justified true belief.” • This means, “believing what is true and having reasons to back it up.” • Three features of knowledge: • Belief • Truth • Justification

4. Belief • Belief is a person’s opinion of how the world is. It is a person’s idea of the arrangement of facts; what they think is true. • Beliefs can be true. • Beliefs can be false. • People hypothesize (suppose) something is true, and then go out an test (check) it. • People assign probabilities to their beliefs. Some things they are sure are true; while other things are less certain. • Do you have to be certain of something for it to be knowledge? • Should the strength of belief be related to the strength of ones justification?

5. Truth • Beliefs are true when they depict things as they are. • Philosophers disagree about the criteria to determine whether something is true or not. Below are three criteria used by many philosophers to establish truth. • Correspondence Theory • Coherence Theory • Pragmatic Theory

6. Correspondence Theory • Most people accept the notion of a reality that exists separate from our thoughts. • This reality is the basis of truth. • In order to be true, our beliefs must correspond (agree) with this external reality. This is called the “correspondence theory of truth.”

7. Coherence Theory • Beliefs must be logically consistent with other true beliefs in order to also be true. This is called the “coherence theory of truth.” • This means that if ones belief is inconsistent with other accepted beliefs, it probably is wrong. • Coherence is like the relationship of the parts of a jigsaw puzzle. One must throw out the pieces that don’t fit. The goal is to make the largest possible “coherent” picture.

8. Pragmatic Theory • This theory says that beliefs are correct if they are useful and allow use to accomplish our objectives in the world. • For example, beliefs about electricity are true, insofar as they allow us to build electrically powered machines, like lights, TVs, and Wiis. • False beliefs are those which are ultimately not useful. • Can you think of something that is useful but not true? • How about something that is true but not useful? Usually truth is established by a mixture of correspondence, coherence, and pragmatic theories.

9. Justification 1 People usually want to know why their belief is true. They want justification. That is why knowledge is defined as “Justified True Belief.” Since beliefs can be true even without evidence (you might make a lucky guess), many believers cannot be sure without sufficient reason. Sufficient Reason--minimum amount of evidence needed to demonstrate something is true. Usually this depends on what you are dealing with. Philosophers disagree on how much is sufficient.

10. Justification 2 Absolute Certainty Philosophers who hold that knowledge must be absolutely certain also think that deductive proof is the main way to justify knowledge. Inductive proofs do NOT give you certainty; they only give you a probability that something is true. Deductive vs. Inductive proofs Deductive proofs example:“Sparky is a dog.” “All dogs bark.” “So Sparky barks.” General rule (All dogs bark) to specific conclusion (So Sparky barks). Inductive proofs example: “I have seen the Sun rise from the East everyday since I was born.” Therefore draw the conclusion, “The Sun must always rise from the East everyday.” Observe a specific event over and over, then conclude a general rule.

11. How we acquire Knowledge(Rationalism vs. Empiricism) Rationalism – usually based on deductive reasoning (thinking to create new knowledge). “Rationalist” philosophers claimed that all knowledge is acquired by deduction from self-evident principles. Empiricism – usually based on inductive reasoning (observing to discover knowledge). Starting from sense perception, you can build up a conception of the world whose parts can be checked against one another to see if they “fit together” (cohere).

12. How we acquire Knowledge(Rationalism vs. Empiricism) Rationalism • The main rationalist philosophers are Descartes, Spinoza, and Leibniz. • The starting point for rational knowledge are “innate ideas” – thoughts that you were born with. • Rationalists believe that you have absolute knowledge only through deduction. All other knowledge is less than absolute.

13. How we acquire Knowledge(Rationalism vs. Empiricism) Empiricism • The main rationalist philosophers are Locke, Hume, and Berkley. • This perception-based approach to knowledge, which is called “empiricism,” does not produce absolute certainty, but it does produce very strong probable evidence. • Locke claims that mind start as “blank slates” without any innate ideas. • Sense perception gives us our ideas of objects in the external world, and reflection gives us our ideas of what exists within the mind.

14. How we acquire Knowledge(Rationalism vs. Empiricism) Any other ways of knowing? • Instincts (a priori knowledge)? • Revelations? • ESP? • Astrology? • Crystal Ball? • Psychic Hotline?

15. Creating/Discovering Knowledge-Building Justified (True?) Beliefs • Sense Perception • Forming Generalizations • Hypotheses • Deducing Conclusions • How to check reliability/Testing • Theories • Scientific Knowledge • Reports from other people/experts

16. Skepticism(The belief that we can’t know) • Absolute Skepticism—can’t know anything. (self-contradictive) • Relative Skepticism—can’t know some things. • Are there limits to knowledge? • A “Skeptic”—a person who criticizes claims in order to clarify exactly how much we know about it. • Isn’t a skeptic stance useful against people who try to push their views on you?

17. Relativism • Are knowledge claims the same for all people at all time during history? • Is knowledge relative to something, like the structure of language, or culture, or economic class?—this is called relativism. • How should we reconcile with people of different points of view?

18. Absolutism • Absolutism: There is only one set of rules/truths for everyone • No ifs, ands, or buts; if interpretation is needed, the “experts” will do it for you! • What if the rules don’t fit a particular situation? • What if two cultures can’t agree what the rules should be?

19. Fallibilism Fallibilism: can’t know things perfectly, but we still must do our best to discern reality in order to make our best decisions; even though we know we might be wrong. All knowledge is provisional and may have to be revised at any instant. Still, for the fallibilist, a belief that has withstood serious scrutiny is a reasonable one to hold as provisional knowledge.