1. Knowledge and Skepticism
Chapter 6

2. Chapter 6: Knowledge and Skepticism
Epistemology The philosophical study of knowledge.
Propositional Knowledge Knowledge of a proposition, or knowing that something is the case.
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3. Chapter 6: Knowledge and Skepticism
Rationalists Those who believe that through unaided reason we can come to know what the world is like.
Empiricists Those who believe that our knowledge of the empirical world comes solely from sense experience.
Skepticism is the view that we lack knowledge in some fundamental way.
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A Priori Knowledge Knowledge gained independently of or prior to sense experience.
A Posteriori Knowledge Knowledge that depends entirely on sense experience.
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Plato’s Rationalism:
Since we clearly do have knowledge, we must derive it from a reliable source—and that source has to be reason.
Reality comprises two worlds: the fleeting world of the physical accessed through sense experience; and the eternal, nonphysical, changeless world of genuine knowledge accessed only through reason.
The Forms: perfect conceptual models for every existing thing, residing only in the eternal world penetrated by reason alone.
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Plato’s Rationalism:
Plato and most other rationalists accept the doctrine of innate knowledge.
Plato: Knowledge of the Forms is already present at birth, inscribed in our minds (our immortal souls) in a previous existence.
Plato: Accessing it is a matter of using reason to recall what we previously knew in another life.
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René Descartes
Sees sense experience as an unreliable source of knowledge and tries to give all our knowledge a foundation as firm as that which supports unshakeable mathematical truths.
Assumes that knowledge requires certainty.
Offers the Dream and Evil Genius Arguments.
His way out of skepticism: “I think, therefore I am.”
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Descartes’ Dream Argument:
1. “There are no certain indications by which we may clearly distinguish wakefulness from sleep.”
2. So it is possible that we are dreaming now and that what we take to be the real world is in fact not real at all.
3. If so, we can’t be certain about anything we think we know through our senses.
4. Therefore, sense experience can yield no knowledge.
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Descartes’ Evil Genius Argument:
Suppose that “some evil genius not less powerful and deceitful, has employed his whole energies in deceiving me.”
We can’t be sure that this is not the case.
And if we are not certain of this, we can’t know anything based on experience.
Therefore, we can’t know anything based on experience.
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Descartes’ Argument Against Skepticism
I can persuade myself of something; I can have thoughts.
If I can persuade myself of something, if I can have thoughts, I must exist. Even an evil genius cannot rob me of this knowledge.
“I think, therefore I am.”
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Descartes’ First Principle of Knowledge:
“[I]t seems to me that already I can establish as a general rule that all things which I perceive very clearly and very distinctly are true.”
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Locke debunks the notion of innate knowledge.
Locke: At birth the mind is unmarked “white paper” void of any ideas until sense experience gives it content.
From sense experience, the mind obtains “all the materials of reason and knowledge.”
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Critics’ main charge against Locke: He has not given us any good reason to think that our sense data are proof of the existence of an external reality.
Locke says we directly experience only our sensations, or ideas; we only indirectly perceive external objects.
Locke asks, What could possibly cause our sense experience if not external objects?
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George Berkeley
Accepts the empiricist notion of our being aware only of sense data but rejects Locke’s belief in the existence of material objects.
Denies that material objects exist independently of our sense experience, insisting that it is logically impossible for physical objects to exist, for we cannot “conceive them existing unconceived.”
Accepts subjective idealism: all that exist are minds and their ideas.
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Berkeley’s Argument Against
the Existence of Material Objects
Material objects cannot exist because their existence would be logically absurd.
The commonsense view is that material objects continue to be even when no one has them in mind. But, says Berkeley, this would mean that they can be conceived of as existing unconceived, that we can think about things that no one is thinking about—a logical contradiction.
Therefore, Berkeley concludes, the claim that material objects exist is false.
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David Hume
Holds that all our knowledge (aside from purely logical truths) is derived from sense perceptions or ideas about those perceptions.
Believes that the mind is empty—a blank slate—until experience gives it content.
Hume is driven to skepticism about the existence of the external world, causation, a continuing self, religious doctrines, and inductive reasoning.
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Hume’s Argument Against Induction
The principle of induction cannot be an a priori truth, because the denial of an a priori truth is self-contradictory, and the denial of the principle of induction is not like that.
It cannot be an a posteriori fact, because no amount of empirical evidence can show it to be true. (To maintain that the principle is an a posteriori fact is equivalent to saying that it can be proved by the principle of induction—which is to beg the question.)
Therefore, the principle of induction cannot be rationally justified.
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The Kantian Compromise
Analytic statement A logical truth whose denial results in a contradiction.
Synthetic statement A statement that is not analytic.
Kant Synthetic a priori knowledge is possible; we can know things about the world, and we can know them independently of or prior to experience.
Kant Because this knowledge is a priori, it is both necessarily true and universally applicable.
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The Kantian Revolution
The conventional view was that knowledge is acquired when the mind conforms to objects—that is, when the mind tracks the external world. Kant proposed the opposite: objects conform to the mind.
Sense experience can match reality because the mind stamps a structure and organization on sense experience.
Synthetic a priori knowledge is possible because the mind’s concepts force an (a priori) order onto (synthetic) experience.
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A Feminist Perspective
Feminist philosophy is an attempt to address the disparagement or subordination of women in philosophy and related fields, and feminist epistemology tries to do the same in theories of knowledge.
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A Feminist Perspective
Louise M. Antony: “Although women were largely ignored by the major philosophers, whenever we were discussed, we were denigrated.”
Elizabeth Anderson: “Various practitioners of feminist epistemology and philosophy of science argue that dominant knowledge practices disadvantage women by (1) excluding them from inquiry, (2) denying them epistemic authority, (3) denigrating their ‘feminine’ cognitive styles and modes of knowledge….”
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A Feminist Perspective
Eve Browning Cole: “[T]here is widespread agreement that the dominant theories of knowledge provided by the Western philosophical tradition have focused on a specific kind of knowledge which is … ‘a commodity of privilege.’”
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A Feminist Perspective
Three Epistemological Paths:
feminist empiricism
feminist standpoint theory
feminist postmodernism
Chapter 6: Knowledge and Skepticism