David Hume(1711-1776)

An Inquiry Concerning Human Understanding

(Text, pp. 327-340)

Revised, 11/16/06

Anthem1

Anthem2

An overall outline of the text

1 Sensation & the Origin of Ideas2 The Nature & Limits of Human Knowledge3 The Nature & Limits of Inductive Reasoning4 The Idea that there is a Necessary Connection

between Cause & Effect5 The Value & Limitations of Skepticism

1. Sensation & the Origin of Ideas(327-8)

The contents of the mind: (1) ideas & (2) impressions (sensations & feelings) -- Ideas (concepts, beliefs, memories, mental images, etc.) are faint & unclear; impressions are strong & vivid.

Ideas are derived from impressions: All [all?] ideas are copies of impressions.

The meaning of ideas depends on impressions [see next slide].

The empirical criterion ofmeaning & truth

"From what impression is that alleged idea derived?"

No impression, no meaning?

No impression, no foundation in reality?

(Text, 328)

2. The Nature & Limits of Human Knowledge (329-331)

Two kinds of ideas(or judgments)

"Hume's Fork"

"All the objects of human reason or inquiry may naturally be divided into two kinds: relations of ideas and matters of fact" (329).

Ideas

Judgments concerning relations of ideas

Judgments concerning matters of fact

("Hume's Fork")

(Text, 329)

Judgments concerning relations of ideas

Intuitively or demonstrably certain Discoverable by thought alone [a priori] Cannot be denied without contradiction

*Hume's examples: the Pythagorean Theorem

3 x 5 = 30 2

On a right triangle, the square of the hypotenuse is equal to the sum of the

squares of the other two sides

The Pythagorean Theorem

5'4'

3'

(hypotenuse)

32 + 42 = 52

(9 + 16 = 25)

Judgments concerning matters of fact

"Every judgment concerning matters of fact can be denied without contradiction" (e.g., "the sun will not rise tomorrow").

Neither intuitively nor demonstrably certain Not discoverable by thought alone [a priori], but

rather on the basis of sense experience [a posteriori]

More specifically,

All judgments concerning matters of fact are based on . . . .

the [more fundamental] belief that there is "a tie or connection" between

cause & effect.

And why do we believe that there is a "tie or connection" between

cause & effect?

Answer: The belief arises entirely from experience [a posteriori, not a priori], namely, the experience of finding that two events (cause & effect) are "constantly conjoined" with each other.

(Text, 330-331)

It is not logically necessary that a particular effect follows a

particular cause;

it is just a fact of experience.

This view leads to Hume's discussion of . . . .

3. The Nature & Limits of Inductive Reasoning

(the problem of induction)

(Text, 331-333)

Hume on Induction

Induction is the process of drawing inferences from past experiences of cause & effect sequences to present or future events.

Hume's point is that an "effect" cannot be validly deduced from its "cause;"

the inference from "cause" to "effect" is based on past experiences of "constant conjunction," and these past experiences . . . .

accustom or habituate us

to believe that one event is the cause of another, which we believe to be the

effect of the prior event.

This is what leads us to believe that . . . .

the future will resemble the past.

It is all a matter of CUSTOM or HABIT.

This is the foundation of . . . .

4. The Idea that there is a Necessary Connection between

Cause & Effect

What, then, is the sense impression from which this idea is derived?

If this is a meaningful (& true?) idea, then (according to Hume) it must be derived from sense impressions.

(Text, 333-4)

There is no sense impression of causal power or necessary

connection of cause & effect, but we do experience . . . .

(1) the spatial contiguity, (2) the temporal succession, and (3) the constant conjunction

of "cause" & "effect."

It is from this experience,

especially the experience of constant conjunction, that the idea of a necessary connection between "cause" &

"effect" arises (or is inferred); but the "inference" is simply a matter of "custom or habit."

This seems to mean that the "inference" here is psycho-logical rather than logical. Actually, there is no experience of the necessary connection between cause and effect. Thus, all factual judgments (which are based on the assumption that there is a necessary connection between cause and effect) are subject to doubt.

No necessity, no certainty.

5. The Value & Limitations of Skepticism

(Text, 334-340)

Hume discusses 5 kinds of skepticism:

(1) "Antecedent" skepticism (2) "Consequent" skepticism (3) Skepticism concerning mathematical

reasoning (4) Extreme skepticism concerning matters

of fact (5) Moderate skepticism

The pro's & con's of "antecedent skepticism" (Text, 334-5)

Criticism of "Cartesian skepticism" -- Is Hume's characterization of Descartes' approach correct? Fair?

The value of the Cartesian approach when used in a "more moderate and reasonable way"

"consequent skepticism"(Text, 335-6)

The nature of "consequent skepticism" Weaker & stronger arguments in support of

consequent skepticism A skeptical critique of epistemic realism

– Common sense ("direct") realism

– Representational realism (reason vs. common sense)

– God & the reliability of sense perceptions

– Skeptical conclusion with regard to epistemic realism

Skepticism concerning mathematical reasoning with regard to space & time

(Text, 336-7)

The idea of the infinite divisibility of space results in "absurdities & contradictions" that raise skeptical doubts as to the reliability of mathematics itself.

The idea of the infinite divisibility of time does the same.

Extreme skepticism concerning knowledge of matters of fact

(Text, 337-8)

"Popular" skepticism with regard to empirical knowledge

"Philosophical" skepticism with regard to empirical knowledge (Hume's own position on this matter)

Hume's criticism of these forms of skepticism: their impracticality & human nature's resistance to them

Moderate Skepticism(Text, 338-340)

Intellectual humility (the majority vs. the learned)The limitation of inquiry to accessible subjects (i.e., the concerns of everyday life)The limits of certainty: two types of human knowledge -- formal (a priori & certain) & empirical (a posteriori & uncertain)

Conclusion on factual reasoning, theology, ethics & aesthetics, & speculative metaphysics

The End