Philosophy as Adventures of Ideas

Week6

Hume’s Skeptical Argument

on Causality and Induction

Kazuyoshi KAMIYAMA

National Institute of Technology, Ibaraki college

2016/1/11

CONTENTS

Descartes’ rationalism

Hume’s skeptical argument on causality and induction

DESCARTES: A RATIONALIST OR DOGMATIST

Descartes was not a skeptic. He was a rationalist or

“dogmatist”(in the sense of the word for ancient

skeptics) who “proved” the existence of God and the

immortality of the soul.

Rationalism

Reason is the chief source and test of knowledge.

A class of truths exists that the intellect can grasp

directly. There are certain rational principles—especially

in logic and mathematics, and even in ethics and

metaphysics—that are so fundamental that to deny them

is to fall into contradiction. (Britanica.com)

Descartes attained:

an absolute certainty on our knowledge about God and

world through deep skeptical meditation！

What Descartes did: Reconstruction of rationalism

which survives the severest doubt

CRITICISM AGAINST CARTESIAN RATIONALISM

John Locke(1632-1704)

When we are born, the mind is like a white paper, not

filled with innate knowledge or ideas.

We know about the world only through experience.

(An Essay Concerning Human Understanding,1690)

Empiricism

All knowledge comes from, and must be tested by, sense

experience.

David Hume(1711–1776)

Empiricism cannot escape from skepticism!

Hume’s Skeptical Argument

on Causality and Induction

D.Hume, A Treatise of Human Nature: Being an Attempt to

introduce the experimental Method of Reasoning into Moral

Subjects. (1739–40)

D.Hume, An Enquiry Concerning Human Understanding (1748)

TWO DESTRUCTIONS

Step1: the destruction of causal relation. Causality

does not give us necessity, or certainty.

Step2: the destruction of induction. Induction cannot

be justified.

HUME’S SKEPTICAL ARGUMENT：A SUMMARY

(1) Any our beliefs about matters of fact beyond sense impressions

and the memories of them (in short, "empirical beliefs”)are not

logical truths. (There is no necessary connection between causes

and effects.) They can be justified only by inductive inferences.

(2) The justification processes of any empirical belief will end with a

hypothesis, which is in Hume‘s formulation, ’that instances of which

we have had no experience, must resemble those of which we have

had experience, and the course of nature continues always

uniformly the same.‘ (or simply, “the future resembles the past.”)

(3) It is logically possible that the future does not resemble the

past.

Therefore,

(4) There can be no deductive justification for the hypothesis.

(5) Any attempt to justify the hypothesis by appealing to an

inductive inference would be circular, since it would assume the

hypothesis itself.

(7) Circular justification is not acceptable.

Therefore,

(8) There can be no inductive justification for the hypothesis.

(9) The only possible ways of justifying some hypothesis are

either by deduction or by induction.

Therefore,

(10) There is no way of justifying the hypothesis.

Coclusion

(11)Since the hypothesis on which we base our empirical beliefs

cannot be justified, there is no justification for them at all.

In my opinion the core of the above argument is the following:

(1) The process of justification of an empirical belief falls into an

infinite regress or ends with a belief that cannot be justified by

itself.

In the former case (the infinite regress case which Hume does

not discuss explicitly) a given belief cannot be justified. In the

latter case (ending with an unjustified belief) it cannot be

justified as well. Therefore it cannot be justified.

(1) can be extended to the following without hurting the argument.

(1) ’The process of justification of an empirical belief falls into an

infinite regress or ends with a belief that cannot be justified by itself

or circular.

In either case the empirical belief cannot be justified.

NOTE

This is Agrippa’s trilemma!

Weintraub (1995) points out that Hume invokes the same

strategy as the Agrippa’s trilemma in his argument against

induction.

COMMENTS BY AYER, RUSSELL

A.J.Ayer (Probability and Evidence,1972)

“Whatever we may think of the conclusion, this is a marvelous

chain of arguments; one of the most brilliant examples of

philosophical reasoning that there has ever been, and also one of

the most influential.”

B.Russell(History of Western Philosophy, 2nd ed.,1961, 645-646)

” Hume’s philosophy , whether true or false, represents the

bankruptcy of eighteenth-century reasonableness.… It was

inevitable that such a self-refutation of rationality should be

followed by a great outburst of irrational faith. … The growth of

unreason throughout the nineteenth century and what has

passed of the twentieth is a natural sequel to Hume’s destruction

of empiricism.”

THE PROBLEM OF INDUCTION

If we accept Hume’s conclusion, we must admit that

we know nothing about tomorrow.

Can we accept it or not? If not, how should we respond

to it?

REFERENCES

Ayer, A.J. (1972): Probability and Evidence, London, Macmillan.

Hume’s Skeptical Challenge to Induction.pdf

Kant's antinomies, From Wikipedia, the free encyclopedia

http://www.britannica.com/topic/rationalism

Weintraub, R. (1995): “What was Hume’s Contribution to the

Problem of Induction?” The Philosophical Quarterly, 45, 460-470.