Editing Raven paradox (section)

====Red herring====
Good<ref>{{cite journal |last1=Good |first1=I. J. |year=1967 |title=The White Shoe is a Red Herring |journal=British Journal for the Philosophy of Science |volume=17 |issue=4 |page=322 |jstor=686774 |doi=10.1093/bjps/17.4.322 }}</ref> gives an example of background knowledge with respect to which the observation of a black raven ''decreases'' the probability that all ravens are black:

{{quote|Suppose that we know we are in one or other of two worlds, and the hypothesis, H, under consideration is that all the ravens in our world are black. We know in advance that in one world there are a hundred black ravens, no non-black ravens, and a million other birds; and that in the other world there are a thousand black ravens, one white raven, and a million other birds. A bird is selected equiprobably at random from all the birds in our world. It turns out to be a black raven. This is strong evidence ... that we are in the second world, wherein not all ravens are black.}}

Good concludes that the white shoe is a "[[red herring]]": Sometimes even a black raven can constitute evidence ''against'' the hypothesis that all ravens are black, so the fact that the observation of a white shoe can support it is not surprising and not worth attention. Nicod's criterion is false, according to Good, and so the paradoxical conclusion does not follow.

Hempel rejected this as a solution to the paradox, insisting that the proposition 'c is a raven and is black' must be considered "by itself and without reference to any other information", and pointing out that it "was emphasized in section 5.2(b) of my article in ''Mind'' ... that the very appearance of paradoxicality in cases like that of the white shoe results in part from a failure to observe this maxim."<ref>{{cite journal | last1 = Hempel | year = 1967 | title = The White Shoe—No Red Herring | journal = The British Journal for the Philosophy of Science | volume = 18 | issue = 3| pages = 239–240| jstor=686596 | doi=10.1093/bjps/18.3.239}}</ref>

The question that then arises is whether the paradox is to be understood in the context of absolutely no background information (as Hempel suggests), or in the context of the background information that we actually possess regarding ravens and black objects, or with regard to all possible configurations of background information.

Good had shown that, for some configurations of background knowledge, Nicod's criterion is false (provided that we are willing to equate "inductively support" with "increase the probability of" – see below). The possibility remained that, with respect to our actual configuration of knowledge, which is very different from Good's example, Nicod's criterion might still be true and so we could still reach the paradoxical conclusion. Hempel, on the other hand, insists our background knowledge itself is the red herring, and that we should consider induction with respect to a condition of perfect ignorance.