About Philosophy 9 ^th ed., Chapter 2
Theory of Knowledge

Descartes' Method of Doubt

The aim: certain knowledge

background: dawn of the scientific revolution

his life overlapped Gallileo's & Newtons
Copernican revolution
much of Aristotelian/Scholastic picture of the world was false

need to reconstruct scientific knowledge on a sure and certain foundation
a method of inquiry or discovery

Method of Inquiry: 4 Rules for the Right Direction of the Mind
1. accept nothing you do not clearly and distinctly know to be true
2. divide big problems into smaller parts
3. take on the easiest things first
4. make periodic reviews to be sure you have left nothing out
Method of Doubt:
- aim: certainty

problem: doubtful assumptions make for even more doubtful conclusions

GIGO {Garbage in, garbage out.}
when you "assume" you make an "ass" out of "u" and "me"

proposal: take nothing for granted and doubt everything that can conceivably be doubted
doubts

the reliability of the senses

the sometimes deceive as in dreams and hallucinations
perhaps they always deceive

dream argument: for all I know it's all a dream or hallucination
"reality" is really virtual

hence the existence of the external (material) world

evidence of bodily existence comes wholly from five the senses (sight, hearing, touch, taste, & smell)
which are unreliable

the truths of mathematics and logic

seem more reliable
but perhaps an evil demon can control my thoughts
in a way that distorts my mathematical judgment

gives me clear and distinct seeming, but misleading "intuitions"
2+2=5 aha! How obvious! the demon makes me think (e.g., glossolia, dream-gibberish)

danger: Skepticism

skepticism holds that there is no knowledge
our beliefs lack adequate justification to qualify as knowledge

deliverance: Cogito Argument

Can I doubt my own existence?
I can doubt my existence as an object -- that I really have a body.
I can't doubt my existence as a thinking thing or subject

If I doubt whether I exist, then I must exist!
Cogito ergo sum (I think therefore I am).
"I am, I exist, is necessarily true each time that I pronounce it, or that I mentally conceive it" (p. 54)

the foundation: certain knowledge of my own "thoughts"

my own existence as a thinker
the existence of the thoughts themselves, e.g.,

the belief that 2+2=4
the visual experience or image of the lectern

the rest of the story

Provable from the thoughts in my mind alone that God exists.
And that this God who provably exists is not a deceiver.
Hence, has not made me so as to be completely & utterly deceived

as I would be by the demon
or if my senses always or generally deceived

Hence, the evidence of my senses can generally be trusted.
Hence, there is this external world which my senses seem to reveal.

Rationalism and Empiricism: Two Responses to Cartesian Doubt

Cartesian legacy

Epistemological turn

questions of the scope and limits of human understanding -- of epistemology & methodology
precede questions of the nature of reality

the Cogito was convincing: the foundational role of consciousness roundly accepted

the only evidence you have of anything is your own inward experiences
of your own private thoughts

judgments (that 2+2=4, that I am standing) and ideas or conceptions (e.g., of equality, of standing)
experiences or sensations (e.g., an itch or an afterimage).

"the rest of the story" seems doubtful

The Cogito only goes to show my own existence

solipsism -- the view that nothing but my own mind exists, or can be known to exist -- beckons

How to proceed, then -- that's the question.

Two issues

the standard of justification: is certainty too high a requirement?
the sources of knowledge

abstract & general reasoning on judgments and conceptions
concrete particular experiences of sensory images or impressions

Rationalism & Empiricism

Descartes' rationalism

the senses don't reveal the true nature of things: they give a false impression
reason -- abstract thought -- corrects these false impressions
it is through reason that we grasp the true underlying natures of things
consider the wax

its sensible characteristics are not what make it what it is
it remains for reason to conceive it as it truly is: as an extended thing

Rationalism: Descartes, Spinoza, Leibniz, "Kant" (more top down)

certainty is the test of knowledge
and only reason -- or abstract thought -- attains to certainty
downplays the value of sensory experience: perception never rises to the level of certainty
truths of math & logic are the models:

Spinoza, e.g., worked out a whole system of the reality
Based on "self-evident" axioms and definitions
On the model of Euclid's system of geometry

Empiricism: Locke, Berkeley, Hume (bottom up)

certainty is too high a standard -- probability needs to be considered
reason only sorts and rearranges the materials sensation provides
all knowledge and thought, consequently, derive from sensation

Leibniz and Rationalism

Descartes psychological criteria of truth & certainty

Clarity & distinctness bespeak certain truth.
Problem: what seems clear and distinct sometimes turns out to be false.

Leibniz's logical distinction

truths of reason (a priori truths or necessities) given their meanings follow from the laws of logic alone

Law of contradiction: a statement and its contradictory cannot both be true
example application: All bachelors are unmarried.

bachelor means "unmarried adult male"
a married bachelor would have to both be and not be married
but that's a contradiction:

so it follows from the law of contradiction (given the meaning of bachelor) that all bachelors are unmarried.
it's a truth of reason

Law of excluded middle: Either a statement or its contradictory are true.
Truths of reason include, most notably, the truths of mathematics.

definitions & axioms spell out the meanings of the terms
then by logical reasoning we derive the theorems

truths of reason are necessary: their opposites are impossible

truths of fact (a posteriori truths, or contingencies) cannot be established by appeal to logic alone

are known through experience or observation
are contingent: their opposites are logically possible (not contradictory)

consider pigs can't fly
very unlikely that a pig could fly -- but a flying pig is not self-contradictory (like a married bachelor)
we deem it unlikely on the basis of our experience (from previous observations) of pigs and flying things

Law of sufficient reason: nothing happens without cause or "sufficient reason"

"no fact can be real or existing and no statement true unless it has a sufficient reason why it should be thus and not otherwise" (p. 61)
for pigs to fly there'd have to be something sufficient to make them fly -- wings or something
logically possible facts are naturally necessitated by causes in accordance with natural laws.

Hume and Empiricism

Rationalism v. Empiricism recapped

Rationalism holds that reasoning is the primary source of knowledge.

from our innate ideas of very high level features of reality (e.g., of God, mind, and matter)
we can logically deduce the general causal structure of the world
works best for a priori knowledge of truths of reason

Empiricism holds that sense experience is the primary source of knowledge.

from our experiences of very low level sensations -- of colors, scents, sounds, etc.
we induce the general causal structure of the world
works best for low level truths of fact

Locke's Empiricism

Question of meaning

compare

abstract philosophical/scientific terms: "matter," "space," "time," "cause," "subject"
concrete familiar terms like "hard," "red," "round," and "sweet".

against innateness

rationalists had argued

such abstract terms are so far removed from sense experience that their meanings couldn't derive from experience
such ideas must be innate in us, or inborn

Locke argues

in order to be understood, all ideas must relate to experience
if an abstract term is such that it can't be related to experience that shows

not that it's innate
but that it's meaningless empty verbiage

tabula rasa: the mind at birth is a blank slate, and all the ideas which it comes to be furnished derive from sensory experience
application to God: infinitely powerful, wise, and good being

worry: all our experiences are finite (whence could the idea of infinity arise)
Locke's solution: we extrapolate from the different degrees of wisdom, strength, and virtue we observe in people to the idea of someone having these in the nth degree, and that's how we form the idea of God.
"two edged sword": if this idea of God can't be derived from experience

the word "God" is meaningless (or, at least it can't mean infinite being)
or else -- contra empiricism -- we understand the concept of an infinite being otherwise than through experience

Humean mechanics

"perceptions": any mental contents

impressions: direct deliverances of sensation
ideas: which we form by

copying: simple ideas
or by combining rearranging or otherwise altering impressions: complex ideas

copy theory

"that all our simple ideas in their first appearance are deriv'd from simple impressions, which are correspondent to them, and which they exactly represent" (67)
that all our complex ideas are built up from simple ones

as molecules from atoms
or (better perhaps) as phrases from words and sentences from phrases.

construction of ideas: a purple triangle

purple impressions get copied in memory => simple idea of purple
triangular impressions get copied in memory => simple idea of triangle
by combining purple and triangle we get the complex idea purple triangle
by combining purple and cow we get purple cow

cow being a complex idea so constructed
thus we represent in thought even nonexistent & fantastic things

Hume's fork: there are two kinds of truth (as Leibniz says)

truths of reason -- there are no married bachelors -- are founded on relations of ideas

since bachelor = unmarried + male
married bachelor is self-contradictory

truths of fact -- there are happy bachelors -- depend for their truth on sense perception

if I observe that bachelor Tom appears to be happy
that's evidence that there are happy bachelors

Skeptical views concerning causation

Consider the "general maxim": Every event has a cause.
It's not a truth of reason as Leibniz supposes

The ideas of beginning and being caused are different.
So there's no contradiction in the idea of something beginning without being caused.

It's not a truth based on observation either

not only because there are events whose causes are unknown (so the evidence is still out)
but because we can only observe

the "constant conjunction" of events -- that smoke does come from fire
never any "necessary connection" of events -- that the smoke had to come from the fire or that the fire necessitated the smoke

Conclusion: Every event has a cause is no sort of truth at all

even particular judgments of necessary connection and causally based predictions are unfounded
that smoke always has followed fire we observe
that smoke always will follow fire

we don't observe
and, in fact, have no rational basis for believing

if we could assume the future will be like the past, that'd do it
but what warrants that assumption?

not a truth of reason
can't be factually supported without circularity

the future always has resembled the past in the past
does not imply the future always will resemble the past on the future
unless we assume that the future resembles the past in this regard also

Kant's Resolution of the Rationalism/Empiricism Debate

Kant's reaction to Hume's skepticism

awoke him from his "dogmatic slumbers": rationalistic beliefs -- as in the principle of sufficient reason -- shown to be unsupported dogmatism
yet unable to accept the skepticism that is the upshot of Humean empiricism
attempt to avoid these two extremes

Kant's resolution

key is understanding the role of consciousness
the structure of consciousness

its unity

"It must be possible for the `I think' to accompany all my representations." (73)
there must be a fundamental mental activity of synthesis -- of holding together all these various thoughts and perceptions that consciousness performs

its application of rules or categories

is the means by which the synthesis is accomplished
perception unifying categories: time & space
comprehension unifying categories: substance, cause-effect, etc.

the relation of the categories to the external world

the world as I experience & conceive it (as a unity) -- things-for-me or phenomena -- must be
experienced as being in time & space
conceived as containing objects (substances) having cause-effect relations

Consequences of Kant's solution: transcendental idealism

distinction:

phenomena, appearances or things-for-us
noumena, transcendent realities, or things-in-themselves

spatiality, temporality, causality, etc. are necessary

for being experienced (i.e., for their being for us)
not for simply being (in-themselves)

cause-effect principle (and other would-be necessary metaphysical truths)

hold of necessity for phenomena (things-for-us)
not for the things-in-themselves

things-in-themselves are transcendent
beyond our experience and comprehension

because we see the world through space-time colored glasses (so to speak)

things as we experience them have to be spatial-temporal
but not the things-themselves

New Turns in Epistmology

Traditional JTB theory of knowledge as
- justified: must have some basis in reason or perception
- true: there's no such thing as false knowledge {just as counterfeit money isn't really money}
- belief: must be believed
Cheating sweetie examples for why all 3 are necessary
- not J:
  - T: my sweetie is cheating on me
  - B: I believe it's so
  - not-J: with no basis (perhaps I'm a jealous fool who always believe it his sweeties even when they're not cheating)
- not T:
  - J: there's a strange pair of shoes under the bed
  - B: I believe she's cheating
  - not-T: she's not (they're her brothers' shoes)
- not B
  - J: there's a strange pair of shoes under the bed
  - T: she is cheating on me (they're her lovers' shoes)
  - not-B: I refuse to believe it (I think to myself "they must be her brothers' shoes")

Coherentism

Traditional foundationalism
- there is a privileged set of beliefs that are self-certifiying
- all other beliefs are based -- inferentially, it's usually said -- on these
- pyramid analogy
- examples
  - Descartes cogito
  - Locke's experience
- correspondence theory of truth: truth = agreement of thought (or assertion) with reality
Coherentist alternative
- beliefs are all mutually supporting
  - none are self-certifying
  - there is no priviledged set
- coherentist analogies
  - Haack's crossword puzzle
  - Neurath's ship at sea
  - the web of beliefs
- holism

coherence theory of truth: truth = agreement of thoughts (or assertions) among each other

Pros & Cons

Pros
- no need to relate beliefs to anything outside beliefs (a sore point with correspondence theory)
- "seems to acknowledge that we do not acquire knowledge piece by piece, but within a mutually reinforcing network" (p. 84)
Cons
- consistent delusion will count as truth under this scheme
  - paranoids who believe everyone is out to get them reinterpret all that happens in the light of that belief
    - if you do them a favor they interpret this as a ploy to get them to let down their defences
    - etc
  - The Evil Demon & brains in a vat scenarios would be inconceivable
    - to imagine such scenarios to imagine consistent-as-can-be sets of beliefs being false
    - According to coherentism this seems to be impossible
    - But it is possible. Ain't it?
- dilemma: privatization of knowledge & truth vs. collectivized belief
  - privitization of knowledge & truth: abandons the ideals of universality & objectivity
  - communalization of belief: do collectives (corporations, governments, communities, etc.) really have beliefs

A Return to Pragamatism

Pragmatism
- knowledge is power by definition
- truth is what works
Practical hard-headed American kind of theory advanced by
- C. S. Peirce {pronounced "purse"} (1839-1914): originator
- William James (1842-1910)
- John Dewey (1859-1952)
A species of coherentism: coherence expands to include practices not just beliefs; actions not just words
- helps allay the objection from consistent delusions: the paranoid's practice is ineffective
- still faces the dilemma
  - abandon hope of universal & objective knowledge & truth (James) : truth for me is what works for me
  - collectivize belief (Pierce): truth is the belief on which the opinions of the scientific community converge
- Bertrand Russell's complaint that pragmatism obscures the notion of truth rings true in the light of the observation that "There are as many pragmatisms as there are pragmatists." (p. 85)
Characteristic doctrines regarding meaning and knowledge
- meaning: "the meaning of a concept is to be found in the practical outcomes of its adoption"
- "knowledge is action-guiding, instrumental, a tool" not an end in itself (as traditionally conceived)
Classic formulations
- Peirce's pragmatist theory of meaning: "what effects, which might have practical bearings, we conceive the object of our conception to have ... is the whole of our conception of the object."

James' pragmatist theory of truth: "Ideas become true just so far as they help us get in satisfactory relations with other parts of our experience."

The Impact of Cognitive Science

Cognitive science is an interdisciplinary program proposing to explain such thought processes as belief-formation, inference, and memory, as species of computation. The central disciplines involve are
- computer science
- psychology
- linguistics
- philosophy
Basic hypothesis: computationalism
- thought is computation
- the brain is a computer
Objection to the basic hypothesis: John Searle's Chinese room argument
imagine you were in a room taking in and returning Chinese symbols according to shape-matching instructions in English in a way that simulated a conversation in Chinese
- you would be acting just like a computer running a natural language understanding program for Chinese
- but you wouldn't, yourself, be understanding a bit of the conversation: the Chinese symbols still wouldn't mean anything to you
- Concluding argument against computationalism
  - Computation can't create meaning (as just shown).
  - Thought has meaning.
  - So, thought can't be computation.
Potential for impacting epistemology
- understanding how the brain computes (if it does) &learning what kind of mechanisms underlie our thoughts will help us understand our limits
- learning this might also help us overcome those limits and improve our ways of knowing

Key Concepts
Chapter 2
category
cogito argument
cognitive science
coherence theory of truth
computationalism
correspondence theory of truth
ideas (simple or complex)
impressions
law of contradiction
law of excluded middle
law of sufficient reason
method of doubt
pragmatism
skepticism
solipsism
truths of reason
truths of fact

LH's Mostly Modern Philosophical Glossary

About Philosophy 9 th ed., Chapter 2 Theory of Knowledge

Descartes' Method of Doubt

Rationalism and Empiricism: Two Responses to Cartesian Doubt

Leibniz and Rationalism

Hume and Empiricism

Kant's Resolution of the Rationalism/Empiricism Debate

New Turns in Epistmology

Coherentism

A Return to Pragamatism

The Impact of Cognitive Science

About Philosophy 9 ^th ed., Chapter 2
Theory of Knowledge