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.