Brandeis University, Philosophy Department
Fall 2003
Brandeis University Web Stite

Knowledge of
the External World

Professor Andreas Teuber
Prof. Teuber

Three Kinds of Knowing:

  • I know Bill Clinton very well (knowledge as acquaintance).
  • I know how to tie my shoe laces, play the piano, ride a bike. (knowing-how).
  • I know that Boston is the capitol of Massachusetts (knowing that).

  • What is Knowledge? (1)

    1. Justified True Belief and its Off-shoots.

    2. Rationalism v. Empiricism

    What is Knowledge? (2)

    1. Descartes' arguments: Losing the world and bringing the world back in.

    2. The Cartesian circle: Is Descartes' reasoning circular?

      a. Descartes (1596-1650) appears to believe (A) that if he clearly and distinctly perceives some proposition p, then it is true that p AND (B) that G-d exists and is no deceiver.
      b. Descartes appears to hold both that "I can know A, only if I first know B" and "I can know B, only if I first know A." Some philosophers believe that Descartes believes both A and B and that he cannot have it both ways. Blackburn puts it this way: "It's like the familiar impasse in the morning, when I need to have some coffee to get out of bed, but I need to get out of bed to make the coffee.

    3. Hume's (1711-1776) objections to Descartes' foundationalism.

    4. The four "ISMS": Rational Foundationalism, Natural Foundationalism, Coherentism, Skepticism.

    Primary and Secondary Qualities

    1. Primary: (extension) and Secondary qualities (sounds, feels, tastes smells, and colors)

    2. Descartes: There is no reason to assume that sensations (secondary qualities: odors, tastes, sounds, colors and feels) resemble their causes. What's "in" here, "in" your mind, need not be anything like what triggered or produced it "out there."

    3. Sensory perception as a trigger for response best suited to Darwinian survival: The evolutionary explanation of sense impressions.

    4.The "look" and "feel" of the world to you or me and the way the world is apart from being seen, felt, or touched.

    5. Descartes: Through reason we can "abstract" everything the mind contributes to our view of the external world; remove, peel away, the odor, smell, taste, color, feel, of a thing and be left with its primary qualities. And what are those? Descartes: these are spatially extended things("res extensa")

    6. Locke (1632-1704): Secondary qualities: "which in truth are nothing in the objects themselves, but powers to produce various sensations in us by their primary qualities, i.e., by the bulk, figure, texture, and motion of their insensible parts, as colors, sounds, tastes, etc."Primary qualities: "original qualities of body which I think we may observe to produce simple ideas in us, viz. solidity, extension, figure, motion or rest, and number."

    Our Knowledge of the External World

    1. The two worlds theory: the world of appearance and the real world; or the manifest image (due to the mind) and the scientific world (which is not due to the mind); or a subjective world v. an objective world.

    2. Berkeley's (1685-1753 problem with Descartes and Locke: What is a spatially extended something with something "in" it? What kind of something is this? What is "solidity"?

      i. Why isn't "solidity" just like any other "secondary quality"?
      ii. Remove the primary qualities from a thing and what's left: an invisible, undetectable, intangible, unreachable, incommunicative, dumb (silent) thing.

    3. Hume: " The scenes of the universe are continually shifting and one object follows another in an uninterrupted succession, but the power or force, which actuates the whole machine, is entirely concealed from us, and never discovers itself in any of the sensible qualities of body."

    4. Wittgenstein (1889-1951: " A nothing would serve just as well as a something about which nothing can be said."

    5. The Kantian (1724-1804) Twist: Things-in-themselves, space, time, cause and effect, categories of the mind, transcendental idealism. Rather think how a real, objective world can get to us, Kant turns that world "upside down" or "inside out" and encourages us to think of it as a presupposition of our being able to see and draw any sort of conclusions at all.



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