Popper claims to solve Hume's problem of induction by explaining that science does not use induction at all, but rather science can be described by the process of putting forward hypotheses and then trying to falsify them. The more severe testing a hypothesis has undergone, the more we should trust it, although it can never be fully proven.

This view definitely has its criticisms, but that's not the point of this post. What I'd like to ask is: What is the relationship with Popper's view and Nelson Goodman's new riddle of induction? I'm having trouble deciding whether the new riddle should still apply to Popper's falsificationism in a modified way.


Here is my understanding of Karl Popper and Nelson Goodman. Both talk about whether and when observations may corroborate a given hypothesis. Popper concludes that observations may falsify, but never affirmatively prove, a statement. Goodman’s New Riddle says nothing about falsification directly, but creates a hypothetical where corroboration and falsification can never be known.

First, Popper. From Popper, "Demarcation", in the Stanford Encyclopedia of Philosophy. http://plato.stanford.edu/entries/popper/#ProbDema

Popper … repudiates induction…, substituting falsifiability in its place. It is easy… to obtain evidence in favour of virtually any theory, and… such ‘corroboration’, as he terms it, should count scientifically only if it is the positive result of a genuinely ‘risky’ prediction, which might conceivably have been false…. In a critical sense, Popper’s theory of demarcation is based upon his perception of the logical asymmetry which holds between verification and falsification: it is logically impossible to conclusively verify a universal proposition by reference to experience…, but a single counter-instance conclusively falsifies the corresponding universal law….

Every genuine scientific theory then, in Popper’s view, is prohibitive, in the sense that it forbids, by implication, particular events or occurrences. As such it can be tested and falsified, but never logically verified. (emphasis in original)

By destroying the corroborative value of an observation, Goodman seems to call even falsification into question. Assume first that, before a future time t, each emerald examined is green. But then introduce a new category, grue. Grue is the color of things examined before time t just in case they are green, but also to other things, not examined before time t, just in case they are blue. If, before time t, a set of emeralds is examined and each is green, then this series confirms the hypothesis that all emeralds are green. However, the same observations, made before time t, also confirm that all emeralds are grue. Thus, before time t, the two hypotheses, "All emeralds are green" and "All emeralds are grue" are both confirmed by the same set of observations. (“The New Riddle of Induction”, in Fact, Fiction, and Forecast. 1983, Harvard University Press, p. 73-75).

Although the truth of one hypothesis implies the falsehood of the other, both are confirmed by observations before time t. Popper's argument does not resolve the riddle.


Goodman's new riddle of induction is old wine in new bottles. The substance behind the problem of induction is the following. People imagine that they arrive at theories by looking at evidence and drawing conclusions from it. But a collection of observations doesn't imply anything at all about the future. So conclusions reached by current evidence may not apply in the future. Goodman's argument just dresses that problem up with definitions. Definitions are shorthand for identifying ideas, e.g. - 'tiger' is shorthand for 'large stripy orange cat etc.' So Goodman just obfuscated the problem.

Popper pointed out that all justification, including induction, is impossible. See "On the sources of knowledge and ignorance" and chapter I of "Realism and the Aim of Science". Arguments use premises and rules of inference and their conclusions are true or good only if the rules and premises are correct. So those premises and rules would have to be (1) proved for the conclusion to be proved, or (2) you have to dogmatically assert the premises and rules are correct. Option (1) leads to infinite regress and is impossible to implement. Option (2) involves giving up on rationality and so is also unacceptable. Popper's solution to this problem is to point out that all ideas are guesses and we can try to sort them out entirely through criticism without any justification. The criticism can be conducted in terms of whether ideas solve problems, rather than in terms of justification. So justification is unnecessary for progress and is also incompatible with progress because it can't be implemented.

  • The funny (though a bit unrelated) thing is, we still talk in terms of justification. – Yechiam Weiss Feb 7 '18 at 13:02
  • Unfortunately, this post shows no understanding of either Goodman's argument or its relation to Popper's position, one can do better by reading Wikipedia. It should also be noted that the author has a history of presenting (his/her reading of) Karl Popper's positions as uncontroversial facts. Popper's "solution" to the problem of induction is seen as non-viable by most philosophers today, no uncontroversial solution is known, see SEP. – Conifold Feb 8 '18 at 22:16
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    @conifold states that I have said something wrong about Goodman without providing any specifics. Since he has stated his ideas without argument I have rejected his assertions without argument and I suggest you do the same.Philosophers say Popper's solution is non-viable. But saying something doesn't make it true. In this case, what they say is accompanied by stating Popper's ideas inaccurately and then refuting a position that Popper never held. – alanf Feb 9 '18 at 8:27

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