explain Hume's problem of induction and evaluate proposed responses, including the appeal to the uniformity of nature and pragmatic justifications

What this dot point is asking

QCAA wants you to grasp the deepest challenge to inductive reasoning. David Hume argued that although we constantly reason from observed cases to unobserved ones, this inference cannot be rationally justified without arguing in a circle. You need to reconstruct Hume's argument precisely, state the role of the uniformity of nature, and evaluate the main responses. This is a high-value link between the reasoning strand and the theory of knowledge.

The answer

What induction assumes

Every inductive inference, from "the sun has always risen" to "this drug has always worked," assumes that unobserved cases resemble observed ones: roughly, that nature is uniform across time and space. Without this assumption, past observations would tell us nothing about the future. Hume's question is simple and devastating: what justifies the assumption that the future will resemble the past?

Hume's argument

Hume, in An Enquiry concerning Human Understanding (1748), argues by elimination. A justification of induction must be either demonstrative (deductive, from relations of ideas) or probable (empirical, from matters of fact).

1. It cannot be demonstrative, because there is no contradiction in supposing the future will differ from the past. A world where bread suddenly stops nourishing is conceivable, so no deductive proof rules it out.
2. It cannot be probable (empirical) without circularity. Any argument that induction has worked before, so it will work again, already uses induction. It assumes the very uniformity it is trying to establish.

Since both routes fail, Hume concludes that our inductive habits rest not on reason but on custom or habit: having seen events conjoined repeatedly, the mind is conditioned to expect the one on seeing the other. Induction is psychologically irresistible but rationally unfounded.

The circularity at the heart of it

The core point is the circle. To justify "the future resembles the past," you cannot say "it always has," because that is itself an inductive inference relying on the principle in question. This is why the problem is so stubborn: any empirical defence of induction presupposes induction.

Responses

• Inductive justification ("it has worked, so it will work"): rejected by Hume as circular.
• The uniformity of nature as a premise: you can make induction valid by adding "nature is uniform" as a premise, but then you must justify that premise, which faces the same dilemma.
• Pragmatic or vindicatory justification (Hans Reichenbach): we cannot prove induction will work, but if any method works, induction will; so it is rational to use it as our best bet. Critics object that this does not show induction is reliable, only that nothing else is guaranteed better.
• Falsificationism (Karl Popper): science does not rely on induction at all; it proceeds by bold conjectures tested by deductive falsification. Critics reply that we still need induction to trust that a theory which has survived testing will keep working (the problem of corroboration), so Popper may dissolve the problem only verbally.
• Dissolving the problem (P. F. Strawson): asking whether induction "as a whole" is justified is like asking whether the law is legal; being reasonable just means, in part, proportioning belief to inductive evidence. Critics say this redescribes the practice rather than vindicating it.

Why it matters

If induction cannot be justified, the entire edifice of empirical science and everyday prediction rests on something other than reason, which is a striking sceptical result. Yet no one can actually abandon induction. The problem therefore sharpens what we mean by rational justification and feeds directly into debates about scientific method and the theory of knowledge.

Try this

Q1. Reconstruct Hume's dilemma about justifying induction. [4 marks]

• Cue. Justification is demonstrative or probable; not demonstrative (non-uniform future conceivable), not probable (circular), so neither works.

Q2. Explain why adding "nature is uniform" as a premise does not solve the problem. [3 marks]

• Cue. That premise itself needs justification and faces the same demonstrative-or-circular dilemma.

Q3. State one objection to Popper's claim that science avoids induction. [2 marks]

• Cue. We still seem to rely on induction to trust that a corroborated theory will keep working.