^Given the great power and usefulness of inductive arguments, it’s no wonder philosophers have had a great interest in showing that those arguments work and how they can be improved.
^One of the great challenges faced by those who attempt to explain and defend the use of inductive inference was given by David Hume in a series of works. In the first of those works, A Treatise of Human Nature, he introduced an attack on induction that became one of the most influential arguments in the history of philosophy.
^The goal of Hume’s argument is to show that, despite its power and usefulness, inductive arguments are not in fact based on reason at all.
According to Hume, the correct conclusion to draw about induction is that it provides us with no reason for our beliefs or actions at all!
^How does Hume establish such a seemingly radical conclusion?
^He begins by noting that in order for inductive arguments to be successful, the uniformity principle—which says that unobserved instances resemble
Theories of Knowledge LECTURE 14 hume’s Attack on induction
observed instances—must be true.
The uniformity principle requires this: For an inductive argument to be successful, past performance must at least resemble the future results in ways that make generalizations about those future results possible.
^Hume’s uniformity principle seems to be extremely plausible. Inductive reasoning can only work as long as the unobserved cases that you’re trying to predict resemble the observed cases on which you base your argument.
T he uniformity principle is one of the basic assumptions at the root of scientific inquiry. As astrophysicist Brian Greene noted,
Science is not describing a universe out there, and we’re separate entities …. We’re part of that universe, we’re made of the same stuff as that universe, of ingredients that behave according to the same laws as they do elsewhere in the universe.
^Hume’s argument is as follows:
1 In order for someone to have reason to believe any matter-of- fact claim about the unobserved, he or she must first have reason to believe that the uniformity principle is true. To make this claim plausible, it would help to think from an internalist
perspective. The uniformity principle is neither self-evident nor something we can know on the basis of immediate experience. Therefore, if you’re an internalist—whether a foundationalist or a coherentist—
Hume’s first claim seems very plausible.
Theories of Knowledge LECTURE 14 hume’s Attack on induction
I f you’re an internalist, then you think that
everything you have reason to believe has to be supported by something else you also have reason to believe, with a few potential exceptions.
If you’re a coherentist, then there are no exceptions;
everything you have reason to believe has to be supported by its coherence with everything else you have reason to believe.
If you’re a foundationalist, then the exceptions are the foundational beliefs. Typically, for
foundationalists, this would include things that are self-evident or things you believe on the basis of immediate experience.
2 All claims are either what Hume calls relations-of-ideas claims or matter-of-fact claims. Matter-of- fact claims can be either true or false. Relations-of-ideas claims are made true by the concepts, or ideas, they involve; they are claims you can know without going out into the world and checking. The claim that all statements can be divided into one of these types, sometimes called Hume’s fork, seems at least somewhat plausible.
3 The uniformity principle is not a relations-of-ideas claim. There is nothing about the meaning of the ideas involved in the claim that unobserved instances resemble
observed instances that would guarantee the truth of that claim.
If all claims are either relations- of-ideas claims or matter-of-fact claims and if the uniformity principle is not a relations-of- ideas claim, then the uniformity principle must be a matter-of- fact claim.
4 Because the uniformity principle says that unobserved instances resemble observed instances, that means the uniformity principle is a claim about the unobserved.
5 Because the uniformity principle is itself a matter-of-fact claim about the unobserved, that means that in order for you to have reason
Theories of Knowledge LECTURE 14 hume’s Attack on induction
B ecause pretty much all of science depends on inductive reasoning, in a nutshell Hume’s conclusion means that we have no good reason to believe any of the information science gives us.
to believe that the uniformity principle is true, you must already have reason to believe that the uniformity principle is true.
^Because the support for the uniformity principle comes from the uniformity principle itself, the justification for the uniformity principle is viciously circular. And if that’s the case, then Hume has the conclusion that he’s
after: We have no good, noncircular reason for believing in the conclusions of inductive arguments.
^Hume’s conclusion is devastating for our everyday beliefs. Hume himself emphasizes that the results of his conclusion mean that we don’t have
good reason to believe that food and drink will nourish us rather than poisoning us—or even that the sun will rise tomorrow as it’s always done in the past.
^Clearly, this is a terrible result. If there is any way to avoid accepting the force of Hume’s argument, we should see if we can seek it out.
^One strategy for rejecting Hume’s argument is to attack the first premise: that in order for you to have reason to believe any matter-of-fact claim about the unobserved, you must first have reason to believe the uniformity principle is true.
^This claim is not obvious. What is obvious is that for you to have good reason to believe the result of an inductive argument, the uniformity principle has to be true. But that’s a far cry from Hume’s claim, which is that for you to have reason to believe in the result of your inductive inference, you have to have reason to believe that the uniformity principle is true.
^If you’re an externalist, you’ll reject Hume’s claim. Just because our having reason to believe in the conclusions of our inductive inferences requires the truth of the uniformity principle, that doesn’t mean we have to give any thought to the uniformity principle itself.
Theories of Knowledge LECTURE 14 hume’s Attack on induction
S o much for Hume’s attack on induction.
Unfortunately, we’re not in the clear yet. In the 20th century, a number of philosophers returned to the question of why we’re allowed to believe the conclusions of our inductive inferences.
]Stroud, Hume.
Swinburne, ed., The Justification of Induction.
]
reAdings
yTheories of Knowledge LECTURE 14 hume’s Attack on induction
QUIZ
1 Which of the following is not a way that induction differs from deduction?
a Induction doesn’t provide certain support for its conclusions.
b The support that the premises of an inductive argument provide for the conclusion often involve probabilities.
c Even if the conclusion of an inductive argument is well supported by the argument, the conclusion still allows for exceptions.
d The conclusions of inductive arguments cannot contain more evidence than is contained in the premises.
2 TrUe or fAlse
David Hume’s uniformity principle, according to which unobserved instances resemble observed instances, lies at the foundation of the natural sciences.
3 David Hume’s argument against the rationality of induction relies on which of the following?
a The truth of internalism about knowledge
b The idea that all claims involve either relations of ideas or matters of fact
c The idea that induction relies on the uniformity principle
d All of the above e None of the above 4 TrUe or fAlse
A coherence theorist can accept all of the premises of David Hume’s argument against the rationality of induction but still reject Hume’s conclusion.
Theories of Knowledge LECTURE 14 QUIZ