2 Epistemology Theory of Knowledge What is knowledge? What is the structure of knowledge? What particular things can I know? What particular things do I know? Do I know x?
3 First Philosophy This is the name that the early modern philosophers gave for the most fundamental starting point for philosophical inquiry. It is the starting point from which all else follows. What discipline can be rightly called First Philosophy? Ancient & Medieval Philosophy: Metaphysics. Modern Philosophy: Epistemology. Why A? Because B. Why B? Because C. Why C? Because D. Why D? Because E. Why E?...etc Why Y? Because Z. Whatever the final questions (Y) happen to be, and whatever the final answers (Z) are, they will be EPISTEMOLOGICAL.
4 Why would Epistemology be First Philosophy? There needs to be a deeper level of inquiry which allows us to know which one is true.
5 What is knowledge anyway? What is the classical definition of knowledge? Knowledge = B+T+J B = Belief T = True J = Justified (i.e. warranted/evidenced)
6 What is the source of knowledge? Empiricism All knowledge ultimately rests on sense experience. Our justification for claiming that we know something about the world must always end with some kind of appeal to sense experience. Rationalism Rationalism: Not all knowledge ultimately rests on sense experience. At least some (maybe even all) knowledge claims can be justified independently of sense experience.
7 Rationalism & Empiricism Cont. What would an Empiricist say? What about math? While we can know mathematical truths, they are just a bunch of definitional truths that don t really tell us anything substantive about the world. What about metaphysics? If we can know metaphysical truths, it will be due to sense experience. E.g., Locke s distinction between primary and secondary qualities. What would a Rationalist say? What about math? We can know these simply by thinking about the matter. These truths are more than trivial definitions, they genuinely tell us something substantive about the world. What about metaphysics? We can know deep metaphysical truths prior to any sense experience. E.g., whatever begins to exist has a cause.
8 Rene Descartes
9 Descartes 17th century philosopher, mathematician, and scientist. The Goal: Find out what we can really know by discovering the foundations of knowledge. Once the foundation is secured, use the epistemic materials available to us that can be found at the foundation to attain further knowledge built on this firm foundation. This further knowledge includes important topics like the existence of God, the external world, and the nature of the mind.
10 But how do I find the epistemic foundation? Descartes Answer: Methodological Skepticism (In other words, methodological doubt). Methodological Skepticism is a method which utilizes extreme forms of doubt so as to eliminate all of one s (potentially) false beliefs until the only beliefs that remain are undoubtable truths. Skepticism is a philosophy which states that genuine knowledge about the world is impossible.
11 Descartes is not a skeptic!
12 Well then what is he? He is a philosopher who wants to determine what one can possibly know (that was a central goal of writing the Meditations). Descartes seeks to defeat skepticism by using it as a tool to find the foundations of knowledge, and rebuild a new edifice of knowledge founded on the most certain of truths. Therefore, Descartes says that we can and do know things!
13 Descartes Plan: Two Phases First Phase: Destruction Use methodological skepticism to destroy all of his beliefs which have the mere possibility of being false. Once he comes across beliefs that cannot possibly be false, then he will have discovered the foundations of knowledge. Second Phase: Construction Uses his foundational knowledge to discover what his essence is. Uses his foundational knowledge to deductively conclude that God exists. Takes what he has thus far established and demonstrate that he can trust his senses after all and that the external world exists.
14 Phase One: Destruction The tools in the skeptic s tool box: The Dream Argument. The God Argument. The Self-Deception Argument.
15 The First Skeptical Scenario: The Dream Argument This argument seeks to undermine all of our particular empirical beliefs. At the moment, we believe all kinds of particular things: E.g., I am sitting in an auditorium; I am listening to a philosophy lecture etc These particular beliefs are based on a series of perceptual images and sensations. But then again, I could have the exact same series of perceptual images and sensations if I were dreaming! Descartes does say however, that these kinds of skeptical scenarios cannot undermine our beliefs in things like shapes and colors (because even these things would be in a dream).
16 The Second Skeptical Scenario: The God Argument 1) Either my creator is, or is not, an all powerful God. 2) If He is all powerful, He could make me so that I (mistakenly) think I see material objects, even though no material objects exist. 3) If He is not all powerful, He might have created me incorrectly, so that I think I see material objects, even though none exist. 4) So, if there is or isn t, an all powerful God, I should not trust my senses.
17 The Second Skeptical Scenario 2.0 But what if it doesn t make sense to say that God would be actively deceiving us? He is omnibenevolent after all. Descartes says: that s ok! Think of a similar yet different scenario where it isn t God who is deceiving you, but an immensely powerful demon. Suppose that this demon has made it his soul purpose to thoroughly deceive us. Thus this modified version of the second argument ensures that the argument still goes through: we cannot trust our experiential faculties.
18 The Third Skeptical Scenario: The Self-Deception Argument Why appeal to the possibility of other deceivers like mad scientists, demons, etc? I could be just the kind of being who is constantly deceiving myself. Perhaps I am just a madman who is (unbeknownst to me) deceiving myself!
19 What Survives the Destructive Phase? Descartes skeptical scenarios undermine just about all of his a posteriori beliefs. All that is left is the a priori. He introspects to find the materials necessary to begin what we call the constructive phase.
20 The Constructive Phase
21 The Constructive Phase
22 The Constructive Phase
23 The Constructive Phase
24 I think, therefore I am.
25 I think, therefore I am.
26 In the words of Descartes: Yet when I turn to the things themselves which I think I perceive very clearly, I am so convinced by them that I spontaneously declare: let whoever can do so deceive me, he will never bring it about that I am nothing, so long as I continue to think I am something; or make it true at some future time that I have never existed, since it is now true that I exist; or bring it about that two and three added together are more or les than five, or anything of this kind in which I see a manifest contradiction. Third Meditation
34 John Locke Empiricist Metaphysical Realist Did not question the existence of the external world
35 Ideas vs Qualities Ideas -What we are directly aware of in perception -Exist only in the mind - Caused by Qualities Qualities -Properties of material objects themselves -Exist outside of the mind -Powers of objects to cause ideas in the mind
37 Primary Qualities l Those qualities that cause ideas in our minds which resemble the qualities themselves l Include features like Solidity, extension, figure,mobility, bulk, weight, and texture
38 Secondary Qualities l Those qualities that cause ideas in our minds which do not resemble the qualities themselves. l One good way to think of secondary qualities is as corresponding to the senses l Color, smell, taste, sound, (felt) temperature
40 Atomism l The view that we can explain the properties of big things in terms of the properties of the smaller things that they are made of.
41 Metaphysical Realism Both Descartes and Locke were metaphysical realists (they believed a world existed independently of our perceptions of it)
42 Idealism l There is no such thing as material substance. l Everything that exists is mental. l Is not the same thing as solipsism. l A monist position
43 Monism vs Dualism l Monism -There is only one kind of substance that makes up the world. -Does not necessarily specify what kind of substance. l Dualism -The world is made of two kinds of fundamentally different substances. (Physical and Mental) -The view of Descartes and Locke
44 George Berkeley -Berkeley was an idealist -Empiricist -Held the view that 'esse is precipi' -Rejected the existence of material substance
45 Esse is Precipi -A phrase Berkeley used to characterize his views on what it means for something to exist. -Put simply, things exist only in being perceived. -This does not mean that Berkeley thought that things like chairs and tables do not really exist. -Things like chairs and tables do indeed exist, but, on Berkeley's view they are actually collections of ideas, rather than objects external to the mind.
46 Berkeley's rejection of material substance -Berkeley denied that material substance existed. -Thought positing the existence of material substance explained nothing. -Argued belief in material substance would lead to skepticism. -Denied it was even possible to conceive of something like material substance.
47 Locke and Berkeley Agree -What we are immediately aware of and directly perceive are ideas in the mind. Disagree -Whether there exist any physical objects outside of the mind -What it means for something to really exist
48 How do we categorize Descartes? What is First Philosophy? Answer: Epistemology Rationalist or Empiricist? Answer: Rationalist Can I know that the external world exists? Answer: Yes, we can demonstrate its existence if we start from the epistemic foundation, and then infer that the external world exists. What is the ultimate nature of the external world? Answer: Metaphysical Realism. The external world is real and mind-independent. It is a realm composed of matter.
49 How do we categorize Locke? What is First Philosophy? Answer: Epistemology Rationalist or Empiricist? Answer: Empiricist Can I know that the external world exists? Answer: That is kind of a silly question to ask. It is very reasonable to believe that it exists due to our sense impressions. If you doubt that it exists, then stick your hand in a fire and see what happens. What is the ultimate nature of the external world? Answer: Metaphysical Realism. The external world is real and mindindependent. It is a realm composed of matter.
50 How do we categorize Berkeley? What is First Philosophy? Answer: Epistemology Rationalist or Empiricist? Answer: Empiricist Can I know that the external world exists? Answer: Yes, because the world is just a collection of ideas in your mind, and I am directly acquainted with my ideas! What is the ultimate nature of the external world? Answer: Metaphysical Idealism. The world is real only in the sense that it is mind-dependent. It is an entirely mental realm.
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